From 54de28d583440404818b0e5d8e9a995580fa481f Mon Sep 17 00:00:00 2001
From: vrustx <279631638@qq.com>
Date: Sun, 7 Jun 2026 22:45:46 +0800
Subject: [PATCH] feat(grid): show column data types in result header (#669)
 (#820)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The data grid header only showed column names, and column types were
available only via tableMeta (open-table view). Arbitrary query results
(e.g. `select * from pg_depend`) therefore showed no type at all, which
is exactly the case the reporter hit.

Backend: add `column_types` to QueryResult (serde-default, backward
compatible) and populate it for the native drivers where the type is
readily available — PostgreSQL, MySQL, SQL Server, ClickHouse. Other
drivers leave it empty for now (no behavior change); schemaless stores
(Mongo/Redis/ES) have no column types.

Frontend: render a type row under each column name in the grid header,
color-coded by type. The type is resolved from tableMeta first (richer,
includes precision) and falls back to the query result's column_types by
index. Add a `showColumnTypesInHeader` setting (default on) and keep the
msgpack tab-result cache compatible. The source-selection logic is
extracted to lib/dataGridColumnType.ts with unit tests.

Co-authored-by: vrustx <vrustx@vrustxdeMac-mini.local>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 .../editor/EditorSettingsDialog.vue           | 16 +++++
 apps/desktop/src/components/grid/DataGrid.vue | 20 +++++++
 apps/desktop/src/i18n/locales/en.ts           |  2 +
 apps/desktop/src/i18n/locales/es.ts           |  3 +
 apps/desktop/src/i18n/locales/it.ts           |  3 +
 apps/desktop/src/i18n/locales/pt-BR.ts        |  3 +
 apps/desktop/src/i18n/locales/zh-CN.ts        |  2 +
 apps/desktop/src/i18n/locales/zh-TW.ts        |  2 +
 apps/desktop/src/lib/dataGridColumnType.ts    | 33 +++++++++++
 apps/desktop/src/lib/tabResultCache.ts        |  4 ++
 apps/desktop/src/stores/settingsStore.ts      |  5 ++
 apps/desktop/src/types/database.ts            |  6 ++
 crates/dbx-core/src/db/clickhouse_driver.rs   | 13 ++++-
 .../dbx-core/src/db/elasticsearch_driver.rs   |  4 ++
 crates/dbx-core/src/db/mysql.rs               | 58 +++++++++++++++++++
 crates/dbx-core/src/db/postgres.rs            |  4 ++
 crates/dbx-core/src/db/rqlite_driver.rs       |  2 +
 crates/dbx-core/src/db/sqlite.rs              |  2 +
 crates/dbx-core/src/db/sqlserver.rs           | 24 +++++++-
 crates/dbx-core/src/query.rs                  | 15 +++++
 crates/dbx-core/src/transfer.rs               |  2 +
 crates/dbx-core/src/types.rs                  |  5 ++
 packages/app-tests/dataGridColumnType.test.ts | 58 +++++++++++++++++++
 23 files changed, 284 insertions(+), 2 deletions(-)
 create mode 100644 apps/desktop/src/lib/dataGridColumnType.ts
 create mode 100644 packages/app-tests/dataGridColumnType.test.ts

diff --git a/apps/desktop/src/components/editor/EditorSettingsDialog.vue b/apps/desktop/src/components/editor/EditorSettingsDialog.vue
index 2f0fbaeea..a0f52e939 100644
--- a/apps/desktop/src/components/editor/EditorSettingsDialog.vue
+++ b/apps/desktop/src/components/editor/EditorSettingsDialog.vue
@@ -116,6 +116,7 @@ const editAppLayout = ref(settingsStore.editorSettings.appLayout);
 const editShowTrayIcon = ref(settingsStore.desktopSettings.show_tray_icon);
 const editIconTheme = ref<DesktopIconTheme>(settingsStore.desktopSettings.icon_theme);
 const editShowColumnCommentsInHeader = ref(settingsStore.editorSettings.showColumnCommentsInHeader);
+const editShowColumnTypesInHeader = ref(settingsStore.editorSettings.showColumnTypesInHeader);
 const editCompactColumnHeaderActions = ref(settingsStore.editorSettings.compactColumnHeaderActions);
 const editRedisScanPageSize = ref(settingsStore.editorSettings.redisScanPageSize);
 const editShortcuts = ref(normalizeShortcutSettings(settingsStore.editorSettings.shortcuts));
@@ -273,6 +274,7 @@ watch(
       editShowTrayIcon.value = settingsStore.desktopSettings.show_tray_icon;
       editIconTheme.value = settingsStore.desktopSettings.icon_theme;
       editShowColumnCommentsInHeader.value = settingsStore.editorSettings.showColumnCommentsInHeader;
+      editShowColumnTypesInHeader.value = settingsStore.editorSettings.showColumnTypesInHeader;
       editCompactColumnHeaderActions.value = settingsStore.editorSettings.compactColumnHeaderActions;
       editRedisScanPageSize.value = settingsStore.editorSettings.redisScanPageSize;
       editShortcuts.value = normalizeShortcutSettings(settingsStore.editorSettings.shortcuts);
@@ -320,6 +322,7 @@ function hasChanges(): boolean {
     editShowTrayIcon.value !== settingsStore.desktopSettings.show_tray_icon ||
     editIconTheme.value !== settingsStore.desktopSettings.icon_theme ||
     editShowColumnCommentsInHeader.value !== settingsStore.editorSettings.showColumnCommentsInHeader ||
+    editShowColumnTypesInHeader.value !== settingsStore.editorSettings.showColumnTypesInHeader ||
     editCompactColumnHeaderActions.value !== settingsStore.editorSettings.compactColumnHeaderActions ||
     editRedisScanPageSize.value !== settingsStore.editorSettings.redisScanPageSize ||
     JSON.stringify(editShortcuts.value) !== JSON.stringify(settingsStore.editorSettings.shortcuts) ||
@@ -354,6 +357,7 @@ async function persistSettings() {
     confirmDangerousSqlExecution: editConfirmDangerousSqlExecution.value,
     appLayout: editAppLayout.value,
     showColumnCommentsInHeader: editShowColumnCommentsInHeader.value,
+    showColumnTypesInHeader: editShowColumnTypesInHeader.value,
     compactColumnHeaderActions: editCompactColumnHeaderActions.value,
     redisScanPageSize: editRedisScanPageSize.value,
     shortcuts: editShortcuts.value,
@@ -401,6 +405,7 @@ function resetDefaults() {
   editShowTrayIcon.value = DEFAULT_DESKTOP_SETTINGS.show_tray_icon;
   editIconTheme.value = DEFAULT_DESKTOP_SETTINGS.icon_theme;
   editShowColumnCommentsInHeader.value = DEFAULT_EDITOR_SETTINGS.showColumnCommentsInHeader;
+  editShowColumnTypesInHeader.value = DEFAULT_EDITOR_SETTINGS.showColumnTypesInHeader;
   editCompactColumnHeaderActions.value = DEFAULT_EDITOR_SETTINGS.compactColumnHeaderActions;
   editRedisScanPageSize.value = DEFAULT_EDITOR_SETTINGS.redisScanPageSize;
   editShortcuts.value = normalizeShortcutSettings(DEFAULT_EDITOR_SETTINGS.shortcuts);
@@ -1569,6 +1574,17 @@ watch(
                   </div>
                   <Switch id="show-column-comments-in-header" v-model="editShowColumnCommentsInHeader" />
                 </div>
+                <div class="flex items-center justify-between gap-4 rounded-md border bg-muted/20 px-3 py-2">
+                  <div class="space-y-1">
+                    <Label for="show-column-types-in-header">
+                      {{ t("settings.showColumnTypesInHeader") }}
+                    </Label>
+                    <p class="text-xs text-muted-foreground">
+                      {{ t("settings.showColumnTypesInHeaderDescription") }}
+                    </p>
+                  </div>
+                  <Switch id="show-column-types-in-header" v-model="editShowColumnTypesInHeader" />
+                </div>
                 <div class="flex items-center justify-between gap-4 rounded-md border bg-muted/20 px-3 py-2">
                   <div class="space-y-1">
                     <Label for="compact-column-header-actions">
diff --git a/apps/desktop/src/components/grid/DataGrid.vue b/apps/desktop/src/components/grid/DataGrid.vue
index cf3c2b9ee..e4e037a9b 100644
--- a/apps/desktop/src/components/grid/DataGrid.vue
+++ b/apps/desktop/src/components/grid/DataGrid.vue
@@ -83,6 +83,7 @@ import { createColumnDrafts } from "@/lib/tableStructureEditorState";
 import type { BuildSingleColumnAlterSqlOptions } from "@/lib/tableStructureEditorSql";
 import { buildTableSelectSql, quoteTableIdentifier } from "@/lib/tableSelectSql";
 import { uuid } from "@/lib/utils";
+import { resolveHeaderColumnType } from "@/lib/dataGridColumnType";
 import {
   canEditExistingTableRows,
   hiveTablePropertiesIndicateTransactional,
@@ -341,6 +342,7 @@ const columnCommentMap = computed(() => {
   return map;
 });
 const showColumnCommentsInHeader = computed(() => settingsStore.editorSettings.showColumnCommentsInHeader);
+const showColumnTypesInHeader = computed(() => settingsStore.editorSettings.showColumnTypesInHeader);
 const compactColumnHeaderActions = computed(() => settingsStore.editorSettings.compactColumnHeaderActions);
 const dataGridRenderMode = computed(() => settingsStore.editorSettings.dataGridRenderMode);
 
@@ -349,6 +351,16 @@ function headerColumnComment(column: string): string {
   return columnCommentMap.value.get(column) || "";
 }
 
+function headerColumnType(column: string, actualColIdx: number): string {
+  if (!showColumnTypesInHeader.value) return "";
+  const resolved = resolveHeaderColumnType({
+    tableColumnType: columnTypeMap.value.get(column),
+    resultColumnTypes: props.result.column_types,
+    actualColIdx,
+  });
+  return resolved ? shortTypeName(resolved) : "";
+}
+
 function shortTypeName(t: string): string {
   const s = t.toLowerCase();
   if (s === "character varying") return "varchar";
@@ -6505,6 +6517,14 @@ const gridContextMenuItems = computed<ContextMenuItem[]>(() => {
                           <span class="min-w-0 truncate leading-4">
                             {{ col.name }}
                           </span>
+                          <span
+                            v-if="headerColumnType(col.name, col.actualColIdx)"
+                            class="min-w-0 truncate text-[10px] font-normal leading-3"
+                            :class="typeColorClass(headerColumnType(col.name, col.actualColIdx))"
+                            :title="headerColumnType(col.name, col.actualColIdx)"
+                          >
+                            {{ headerColumnType(col.name, col.actualColIdx) }}
+                          </span>
                           <span
                             v-if="headerColumnComment(col.name)"
                             class="min-w-0 truncate text-[10px] font-normal leading-3 text-muted-foreground"
diff --git a/apps/desktop/src/i18n/locales/en.ts b/apps/desktop/src/i18n/locales/en.ts
index fef4ce32a..f8074f77b 100644
--- a/apps/desktop/src/i18n/locales/en.ts
+++ b/apps/desktop/src/i18n/locales/en.ts
@@ -1643,6 +1643,8 @@ export default {
     dataGridDisplay: "Data grid display",
     showColumnCommentsInHeader: "Show column comments under names",
     showColumnCommentsInHeaderDescription: "Display table column comments directly below grid column names.",
+    showColumnTypesInHeader: "Show column types under names",
+    showColumnTypesInHeaderDescription: "Display each column's data type directly below grid column names.",
     compactColumnHeaderActions: "Compact column header tools",
     compactColumnHeaderActionsDescription:
       "Move formatter and local filter tools into a more menu so column names get priority.",
diff --git a/apps/desktop/src/i18n/locales/es.ts b/apps/desktop/src/i18n/locales/es.ts
index 8353208fd..4c28fc43f 100644
--- a/apps/desktop/src/i18n/locales/es.ts
+++ b/apps/desktop/src/i18n/locales/es.ts
@@ -1530,6 +1530,9 @@ export default {
     showColumnCommentsInHeader: "Mostrar comentarios bajo los nombres",
     showColumnCommentsInHeaderDescription:
       "Muestra los comentarios de columnas directamente debajo del nombre de la columna.",
+    showColumnTypesInHeader: "Mostrar tipos de columna bajo los nombres",
+    showColumnTypesInHeaderDescription:
+      "Muestra el tipo de dato de cada columna directamente debajo del nombre de la columna.",
     compactColumnHeaderActions: "Compactar herramientas del encabezado",
     compactColumnHeaderActionsDescription:
       "Mueve formatear y filtrar a un menú de más acciones para priorizar el nombre de columna.",
diff --git a/apps/desktop/src/i18n/locales/it.ts b/apps/desktop/src/i18n/locales/it.ts
index 8da5646f3..8a17a4aca 100644
--- a/apps/desktop/src/i18n/locales/it.ts
+++ b/apps/desktop/src/i18n/locales/it.ts
@@ -1673,6 +1673,9 @@ export default {
     showColumnCommentsInHeader: "Mostra i commenti delle colonne sotto i nomi",
     showColumnCommentsInHeaderDescription:
       "Visualizza i commenti delle colonne della tabella direttamente sotto i nomi delle colonne nella griglia.",
+    showColumnTypesInHeader: "Mostra i tipi di colonna sotto i nomi",
+    showColumnTypesInHeaderDescription:
+      "Visualizza il tipo di dato di ciascuna colonna direttamente sotto i nomi delle colonne nella griglia.",
     compactColumnHeaderActions: "Strumenti intestazione colonna compatti",
     compactColumnHeaderActionsDescription:
       "Sposta gli strumenti del formattatore e dei filtri locali in un menu 'altro' in modo che i nomi delle colonne abbiano la priorità.",
diff --git a/apps/desktop/src/i18n/locales/pt-BR.ts b/apps/desktop/src/i18n/locales/pt-BR.ts
index 257cc063b..ecb0c46da 100644
--- a/apps/desktop/src/i18n/locales/pt-BR.ts
+++ b/apps/desktop/src/i18n/locales/pt-BR.ts
@@ -1663,6 +1663,9 @@ export default {
     showColumnCommentsInHeader: "Mostrar comentários de coluna sob os nomes",
     showColumnCommentsInHeaderDescription:
       "Exibir comentários de colunas da tabela diretamente abaixo dos nomes das colunas da grade.",
+    showColumnTypesInHeader: "Mostrar tipos de coluna sob os nomes",
+    showColumnTypesInHeaderDescription:
+      "Exibir o tipo de dado de cada coluna diretamente abaixo dos nomes das colunas da grade.",
     compactColumnHeaderActions: "Ferramentas compactas no cabeçalho da coluna",
     compactColumnHeaderActionsDescription:
       "Mover as ferramentas de formatação e filtro local para um menu de mais opções para que os nomes das colunas tenham prioridade.",
diff --git a/apps/desktop/src/i18n/locales/zh-CN.ts b/apps/desktop/src/i18n/locales/zh-CN.ts
index c68783ef3..49570d87d 100644
--- a/apps/desktop/src/i18n/locales/zh-CN.ts
+++ b/apps/desktop/src/i18n/locales/zh-CN.ts
@@ -1612,6 +1612,8 @@ export default {
     dataGridDisplay: "数据表格显示",
     showColumnCommentsInHeader: "在字段名下方显示注释",
     showColumnCommentsInHeaderDescription: "把表字段注释直接显示在结果表头字段名下方。",
+    showColumnTypesInHeader: "在字段名下方显示数据类型",
+    showColumnTypesInHeaderDescription: "把每个字段的数据类型直接显示在结果表头字段名下方。",
     compactColumnHeaderActions: "收起字段表头工具",
     compactColumnHeaderActionsDescription: "将格式化、本地筛选收进更多菜单，优先显示字段名称。",
     sidebarActivation: "侧边栏打开方式",
diff --git a/apps/desktop/src/i18n/locales/zh-TW.ts b/apps/desktop/src/i18n/locales/zh-TW.ts
index 65b797cbb..2fc8e26de 100644
--- a/apps/desktop/src/i18n/locales/zh-TW.ts
+++ b/apps/desktop/src/i18n/locales/zh-TW.ts
@@ -1586,6 +1586,8 @@ export default {
     dataGridDisplay: "資料表格顯示",
     showColumnCommentsInHeader: "在欄位名稱下方顯示註解",
     showColumnCommentsInHeaderDescription: "直接在資料表格欄位名稱下方顯示資料表欄位註解。",
+    showColumnTypesInHeader: "在欄位名稱下方顯示資料類型",
+    showColumnTypesInHeaderDescription: "直接在資料表格欄位名稱下方顯示每個欄位的資料類型。",
     compactColumnHeaderActions: "收起欄位表頭工具",
     compactColumnHeaderActionsDescription: "將格式設定和本機篩選工具移到更多選單，讓欄位名稱優先顯示。",
     sidebarActivation: "側邊欄開啟方式",
diff --git a/apps/desktop/src/lib/dataGridColumnType.ts b/apps/desktop/src/lib/dataGridColumnType.ts
new file mode 100644
index 000000000..8da5fe07c
--- /dev/null
+++ b/apps/desktop/src/lib/dataGridColumnType.ts
@@ -0,0 +1,33 @@
+/**
+ * Resolve the data type to display in a data-grid column header.
+ *
+ * Two sources can supply a column's type:
+ *  - Table metadata (only when a table is open): matched **by column name**,
+ *    richer because it carries precision/scale. Preferred.
+ *  - `QueryResult.column_types` (any query): parallel to `result.columns`, so
+ *    it must be read **by index**. Used as a fallback for arbitrary queries
+ *    that have no table metadata (e.g. `select * from pg_depend`).
+ *
+ * Returns `undefined` when neither source has a non-empty type, so callers can
+ * simply hide the type row.
+ */
+export interface HeaderColumnTypeSources {
+  /** Type from table metadata for this column (looked up by name), if any. */
+  tableColumnType?: string;
+  /** `QueryResult.column_types`, parallel to `result.columns` (by index). */
+  resultColumnTypes?: readonly string[];
+  /** Index of the column within `result.columns`. */
+  actualColIdx: number;
+}
+
+export function resolveHeaderColumnType({
+  tableColumnType,
+  resultColumnTypes,
+  actualColIdx,
+}: HeaderColumnTypeSources): string | undefined {
+  const fromMeta = tableColumnType?.trim();
+  if (fromMeta) return fromMeta;
+
+  const fromResult = resultColumnTypes?.[actualColIdx]?.trim();
+  return fromResult ? fromResult : undefined;
+}
diff --git a/apps/desktop/src/lib/tabResultCache.ts b/apps/desktop/src/lib/tabResultCache.ts
index 9978231ca..f5d01cd70 100644
--- a/apps/desktop/src/lib/tabResultCache.ts
+++ b/apps/desktop/src/lib/tabResultCache.ts
@@ -29,6 +29,7 @@ export interface TabResultSnapshot {
 
 interface ColumnarQueryResult {
   columns: string[];
+  column_types?: string[];
   columnValues: CellValue[][];
   rowCount: number;
   affected_rows: number;
@@ -111,6 +112,7 @@ function stripSessionIds(result: QueryResult | undefined): QueryResult | undefin
   if (!result) return undefined;
   return {
     columns: [...result.columns],
+    column_types: result.column_types ? [...result.column_types] : undefined,
     rows: result.rows.map((row) => [...row]),
     affected_rows: result.affected_rows,
     execution_time_ms: result.execution_time_ms,
@@ -129,6 +131,7 @@ function toColumnarResult(result: QueryResult | undefined): ColumnarQueryResult
   const columnValues = result.columns.map((_, colIndex) => result.rows.map((row) => row[colIndex] ?? null));
   return removeUndefinedFields({
     columns: [...result.columns],
+    column_types: result.column_types ? [...result.column_types] : undefined,
     columnValues,
     rowCount: result.rows.length,
     affected_rows: result.affected_rows,
@@ -145,6 +148,7 @@ function fromColumnarResult(result: ColumnarQueryResult | undefined): QueryResul
   );
   return {
     columns: [...result.columns],
+    column_types: result.column_types ? [...result.column_types] : undefined,
     rows,
     affected_rows: result.affected_rows,
     execution_time_ms: result.execution_time_ms,
diff --git a/apps/desktop/src/stores/settingsStore.ts b/apps/desktop/src/stores/settingsStore.ts
index 85e42ac2e..5766b7f44 100644
--- a/apps/desktop/src/stores/settingsStore.ts
+++ b/apps/desktop/src/stores/settingsStore.ts
@@ -246,6 +246,7 @@ export interface EditorSettings {
   redisScanPageSize: number;
   mongoViewMode: "document" | "table";
   showColumnCommentsInHeader: boolean;
+  showColumnTypesInHeader: boolean;
   compactColumnHeaderActions: boolean;
   dataGridRenderMode: DataGridRenderMode;
   structureEditorDensity: StructureEditorDensity;
@@ -311,6 +312,7 @@ export const DEFAULT_EDITOR_SETTINGS: EditorSettings = {
   redisScanPageSize: 1000,
   mongoViewMode: "document",
   showColumnCommentsInHeader: false,
+  showColumnTypesInHeader: true,
   compactColumnHeaderActions: true,
   dataGridRenderMode: "canvas",
   structureEditorDensity: "compact",
@@ -466,6 +468,7 @@ export function normalizeEditorSettings(settings: Partial<EditorSettings>, exist
     mongoViewMode: settings.mongoViewMode === "table" ? "table" : DEFAULT_EDITOR_SETTINGS.mongoViewMode,
     showColumnCommentsInHeader:
       settings.showColumnCommentsInHeader ?? DEFAULT_EDITOR_SETTINGS.showColumnCommentsInHeader,
+    showColumnTypesInHeader: settings.showColumnTypesInHeader ?? DEFAULT_EDITOR_SETTINGS.showColumnTypesInHeader,
     compactColumnHeaderActions:
       settings.compactColumnHeaderActions ?? DEFAULT_EDITOR_SETTINGS.compactColumnHeaderActions,
     dataGridRenderMode: normalizeDataGridRenderMode(settings.dataGridRenderMode),
@@ -648,6 +651,8 @@ export const useSettingsStore = defineStore("settings", () => {
     if (partial.mongoViewMode !== undefined) editorSettings.value.mongoViewMode = partial.mongoViewMode;
     if (partial.showColumnCommentsInHeader !== undefined)
       editorSettings.value.showColumnCommentsInHeader = partial.showColumnCommentsInHeader;
+    if (partial.showColumnTypesInHeader !== undefined)
+      editorSettings.value.showColumnTypesInHeader = partial.showColumnTypesInHeader;
     if (partial.compactColumnHeaderActions !== undefined)
       editorSettings.value.compactColumnHeaderActions = partial.compactColumnHeaderActions;
     if (partial.dataGridRenderMode !== undefined)
diff --git a/apps/desktop/src/types/database.ts b/apps/desktop/src/types/database.ts
index 4ce933cee..b8cb2b5a8 100644
--- a/apps/desktop/src/types/database.ts
+++ b/apps/desktop/src/types/database.ts
@@ -236,6 +236,12 @@ export interface TriggerInfo {
 
 export interface QueryResult {
   columns: string[];
+  /**
+   * Database type name for each column, parallel to `columns`. Optional and may
+   * be shorter/empty when a driver cannot supply types (schemaless stores,
+   * fallback query paths, older backends). Consumers must tolerate gaps.
+   */
+  column_types?: string[];
   rows: (string | number | boolean | null)[][];
   affected_rows: number;
   execution_time_ms: number;
diff --git a/crates/dbx-core/src/db/clickhouse_driver.rs b/crates/dbx-core/src/db/clickhouse_driver.rs
index 83b9e2789..8ed936d88 100644
--- a/crates/dbx-core/src/db/clickhouse_driver.rs
+++ b/crates/dbx-core/src/db/clickhouse_driver.rs
@@ -148,13 +148,23 @@ fn query_result_row_limit(max_rows: Option<usize>) -> usize {
 
 fn limited_query_result(result: ChJsonResult, execution_time_ms: u128, max_rows: Option<usize>) -> QueryResult {
     let columns: Vec<String> = result.meta.iter().map(|c| c.name.clone()).collect();
+    let column_types: Vec<String> = result.meta.iter().map(|c| c._type.clone()).collect();
     let mut rows = result.data;
     let row_limit = query_result_row_limit(max_rows);
     let truncated = rows.len() > row_limit;
     if truncated {
         rows.truncate(row_limit);
     }
-    QueryResult { columns, rows, affected_rows: 0, execution_time_ms, truncated, session_id: None, has_more: false }
+    QueryResult {
+        columns,
+        column_types,
+        rows,
+        affected_rows: 0,
+        execution_time_ms,
+        truncated,
+        session_id: None,
+        has_more: false,
+    }
 }
 
 pub async fn test_connection(client: &ChClient, timeout: Duration) -> Result<(), String> {
@@ -259,6 +269,7 @@ pub async fn execute_query_with_max_rows(
         }
         Ok(QueryResult {
             columns: vec![],
+            column_types: Vec::new(),
             rows: vec![],
             affected_rows: 0,
             execution_time_ms: start.elapsed().as_millis(),
diff --git a/crates/dbx-core/src/db/elasticsearch_driver.rs b/crates/dbx-core/src/db/elasticsearch_driver.rs
index 7773aaadb..d1eb53f55 100644
--- a/crates/dbx-core/src/db/elasticsearch_driver.rs
+++ b/crates/dbx-core/src/db/elasticsearch_driver.rs
@@ -421,6 +421,7 @@ pub async fn execute_rest_query(client: &EsClient, input: &str) -> Result<crate:
 
         Ok(crate::types::QueryResult {
             columns: all_keys,
+            column_types: Vec::new(),
             rows,
             affected_rows: total,
             execution_time_ms: start.elapsed().as_millis(),
@@ -434,6 +435,7 @@ pub async fn execute_rest_query(client: &EsClient, input: &str) -> Result<crate:
             let row_count = rows.len() as u64;
             Ok(crate::types::QueryResult {
                 columns,
+                column_types: Vec::new(),
                 rows,
                 affected_rows: row_count,
                 execution_time_ms: start.elapsed().as_millis(),
@@ -445,6 +447,7 @@ pub async fn execute_rest_query(client: &EsClient, input: &str) -> Result<crate:
             let pretty = serde_json::to_string_pretty(&body).unwrap_or_else(|_| body.to_string());
             Ok(crate::types::QueryResult {
                 columns: vec!["status".to_string(), "response".to_string()],
+                column_types: Vec::new(),
                 rows: vec![vec![serde_json::Value::Number(status.into()), serde_json::Value::String(pretty)]],
                 affected_rows: 0,
                 execution_time_ms: start.elapsed().as_millis(),
@@ -457,6 +460,7 @@ pub async fn execute_rest_query(client: &EsClient, input: &str) -> Result<crate:
         let pretty = serde_json::to_string_pretty(&body).unwrap_or_else(|_| body.to_string());
         Ok(crate::types::QueryResult {
             columns: vec!["status".to_string(), "response".to_string()],
+            column_types: Vec::new(),
             rows: vec![vec![serde_json::Value::Number(status.into()), serde_json::Value::String(pretty)]],
             affected_rows: 0,
             execution_time_ms: start.elapsed().as_millis(),
diff --git a/crates/dbx-core/src/db/mysql.rs b/crates/dbx-core/src/db/mysql.rs
index dec96660e..b376ad595 100644
--- a/crates/dbx-core/src/db/mysql.rs
+++ b/crates/dbx-core/src/db/mysql.rs
@@ -187,6 +187,42 @@ fn mysql_bytes_to_json(bytes: Vec<u8>, column: &mysql_async::Column) -> serde_js
     serde_json::Value::String(String::from_utf8_lossy(&bytes).to_string())
 }
 
+/// Map a MySQL column to a user-facing type name for the result-grid header.
+/// Returns the bare lowercase type name (no length/precision/signedness), which
+/// is enough for display; unknown variants fall back to a lowercased debug name.
+fn mysql_column_type_name(ty: ColumnType) -> String {
+    use mysql_async::consts::ColumnType::*;
+    match ty {
+        MYSQL_TYPE_TINY => "tinyint",
+        MYSQL_TYPE_SHORT => "smallint",
+        MYSQL_TYPE_INT24 => "mediumint",
+        MYSQL_TYPE_LONG => "int",
+        MYSQL_TYPE_LONGLONG => "bigint",
+        MYSQL_TYPE_FLOAT => "float",
+        MYSQL_TYPE_DOUBLE => "double",
+        MYSQL_TYPE_DECIMAL | MYSQL_TYPE_NEWDECIMAL => "decimal",
+        MYSQL_TYPE_BIT => "bit",
+        MYSQL_TYPE_YEAR => "year",
+        MYSQL_TYPE_DATE | MYSQL_TYPE_NEWDATE => "date",
+        MYSQL_TYPE_TIME | MYSQL_TYPE_TIME2 => "time",
+        MYSQL_TYPE_DATETIME | MYSQL_TYPE_DATETIME2 => "datetime",
+        MYSQL_TYPE_TIMESTAMP | MYSQL_TYPE_TIMESTAMP2 => "timestamp",
+        MYSQL_TYPE_JSON => "json",
+        MYSQL_TYPE_ENUM => "enum",
+        MYSQL_TYPE_SET => "set",
+        MYSQL_TYPE_TINY_BLOB => "tinyblob",
+        MYSQL_TYPE_MEDIUM_BLOB => "mediumblob",
+        MYSQL_TYPE_LONG_BLOB => "longblob",
+        MYSQL_TYPE_BLOB => "blob",
+        MYSQL_TYPE_VARCHAR | MYSQL_TYPE_VAR_STRING => "varchar",
+        MYSQL_TYPE_STRING => "char",
+        MYSQL_TYPE_GEOMETRY => "geometry",
+        MYSQL_TYPE_NULL => "null",
+        other => return format!("{:?}", other).to_lowercase(),
+    }
+    .to_string()
+}
+
 fn mysql_value_to_json(row: &mysql_async::Row, idx: usize) -> serde_json::Value {
     let Some(column) = row.columns_ref().get(idx) else {
         return serde_json::Value::Null;
@@ -1251,6 +1287,8 @@ async fn execute_result_set_with_text_protocol_on_conn(
 ) -> Result<QueryResult, String> {
     let mut result = conn.query_iter(sql).await.map_err(|e| e.to_string())?;
     let columns: Vec<String> = result.columns_ref().iter().map(|c| c.name_str().to_string()).collect();
+    let column_types: Vec<String> =
+        result.columns_ref().iter().map(|c| mysql_column_type_name(c.column_type())).collect();
 
     let mut result_rows: Vec<Vec<serde_json::Value>> = Vec::new();
     let mut stream = result
@@ -1275,6 +1313,7 @@ async fn execute_result_set_with_text_protocol_on_conn(
 
     Ok(QueryResult {
         columns,
+        column_types,
         rows: result_rows,
         affected_rows: 0,
         execution_time_ms: start.elapsed().as_millis(),
@@ -1292,6 +1331,8 @@ async fn execute_result_set_with_prepared_protocol_on_conn(
 ) -> Result<QueryResult, String> {
     let mut result = conn.exec_iter(sql, ()).await.map_err(|e| e.to_string())?;
     let columns: Vec<String> = result.columns_ref().iter().map(|c| c.name_str().to_string()).collect();
+    let column_types: Vec<String> =
+        result.columns_ref().iter().map(|c| mysql_column_type_name(c.column_type())).collect();
 
     let mut result_rows: Vec<Vec<serde_json::Value>> = Vec::new();
     let mut stream = result
@@ -1316,6 +1357,7 @@ async fn execute_result_set_with_prepared_protocol_on_conn(
 
     Ok(QueryResult {
         columns,
+        column_types,
         rows: result_rows,
         affected_rows: 0,
         execution_time_ms: start.elapsed().as_millis(),
@@ -1378,6 +1420,7 @@ pub async fn execute_query_on_conn_with_max_rows(
 
         Ok(QueryResult {
             columns: vec![],
+            column_types: Vec::new(),
             rows: vec![],
             affected_rows,
             execution_time_ms: start.elapsed().as_millis(),
@@ -1566,6 +1609,21 @@ mod tests {
     use super::*;
     use mysql_async::consts::ColumnFlags;
 
+    #[test]
+    fn mysql_column_type_names_map_to_friendly_names() {
+        use mysql_async::consts::ColumnType::*;
+        assert_eq!(mysql_column_type_name(MYSQL_TYPE_TINY), "tinyint");
+        assert_eq!(mysql_column_type_name(MYSQL_TYPE_LONG), "int");
+        assert_eq!(mysql_column_type_name(MYSQL_TYPE_LONGLONG), "bigint");
+        assert_eq!(mysql_column_type_name(MYSQL_TYPE_NEWDECIMAL), "decimal");
+        assert_eq!(mysql_column_type_name(MYSQL_TYPE_VARCHAR), "varchar");
+        assert_eq!(mysql_column_type_name(MYSQL_TYPE_VAR_STRING), "varchar");
+        assert_eq!(mysql_column_type_name(MYSQL_TYPE_STRING), "char");
+        assert_eq!(mysql_column_type_name(MYSQL_TYPE_DATETIME), "datetime");
+        assert_eq!(mysql_column_type_name(MYSQL_TYPE_JSON), "json");
+        assert_eq!(mysql_column_type_name(MYSQL_TYPE_BLOB), "blob");
+    }
+
     #[test]
     fn mysql_with_queries_are_treated_as_result_sets() {
         let sql = "WITH RECURSIVE org_tree AS (SELECT 1 AS id) SELECT id FROM org_tree";
diff --git a/crates/dbx-core/src/db/postgres.rs b/crates/dbx-core/src/db/postgres.rs
index 3b27c6813..60c4fed05 100644
--- a/crates/dbx-core/src/db/postgres.rs
+++ b/crates/dbx-core/src/db/postgres.rs
@@ -692,6 +692,7 @@ async fn execute_select_prepared(
         truncated,
         session_id: None,
         has_more: false,
+        column_types,
     })
 }
 
@@ -741,6 +742,7 @@ async fn execute_select_text(
         truncated,
         session_id: None,
         has_more: false,
+        column_types: Vec::new(),
     })
 }
 
@@ -1434,6 +1436,7 @@ pub async fn execute_query_with_max_rows(
             truncated: false,
             session_id: None,
             has_more: false,
+            column_types: Vec::new(),
         })
     }
 }
@@ -1519,6 +1522,7 @@ async fn execute_query_with_max_rows_inner(
             truncated: false,
             session_id: None,
             has_more: false,
+            column_types: Vec::new(),
         })
     }
 }
diff --git a/crates/dbx-core/src/db/rqlite_driver.rs b/crates/dbx-core/src/db/rqlite_driver.rs
index 1cfeab004..316fbee3b 100644
--- a/crates/dbx-core/src/db/rqlite_driver.rs
+++ b/crates/dbx-core/src/db/rqlite_driver.rs
@@ -293,6 +293,7 @@ pub async fn execute_query_with_max_rows(
         let affected_rows = result.rows_affected.unwrap_or(0);
         Ok(QueryResult {
             columns: vec![],
+            column_types: Vec::new(),
             rows: vec![],
             affected_rows,
             execution_time_ms: start.elapsed().as_millis(),
@@ -340,6 +341,7 @@ fn query_result_from_rqlite_result(
     }
     QueryResult {
         columns: result.columns,
+        column_types: Vec::new(),
         rows: result.values,
         affected_rows: 0,
         execution_time_ms,
diff --git a/crates/dbx-core/src/db/sqlite.rs b/crates/dbx-core/src/db/sqlite.rs
index 1b3682b58..fcd0067a9 100644
--- a/crates/dbx-core/src/db/sqlite.rs
+++ b/crates/dbx-core/src/db/sqlite.rs
@@ -637,6 +637,7 @@ fn execute_query_blocking(pool: &SqliteHandle, sql: &str, max_rows: Option<usize
 
             Ok(QueryResult {
                 columns,
+                column_types: Vec::new(),
                 rows: result_rows,
                 affected_rows: 0,
                 execution_time_ms: start.elapsed().as_millis(),
@@ -648,6 +649,7 @@ fn execute_query_blocking(pool: &SqliteHandle, sql: &str, max_rows: Option<usize
             conn.execute_batch(sql).map_err(|e| e.to_string())?;
             Ok(QueryResult {
                 columns: vec![],
+                column_types: Vec::new(),
                 rows: vec![],
                 affected_rows: conn.changes(),
                 execution_time_ms: start.elapsed().as_millis(),
diff --git a/crates/dbx-core/src/db/sqlserver.rs b/crates/dbx-core/src/db/sqlserver.rs
index 096448bd2..738022daa 100644
--- a/crates/dbx-core/src/db/sqlserver.rs
+++ b/crates/dbx-core/src/db/sqlserver.rs
@@ -98,6 +98,17 @@ fn columns_from_metadata(metadata: &tiberius::ResultMetadata) -> Vec<String> {
     metadata.columns().iter().map(|c| c.name().to_string()).collect()
 }
 
+/// Map a tiberius column to a user-facing type name for the result-grid header.
+/// Uses the TDS column-type debug name lowercased; good enough for display, with
+/// no risk of mismatching the enum variants across tiberius versions.
+fn sqlserver_column_type_name(column: &tiberius::Column) -> String {
+    format!("{:?}", column.column_type()).to_lowercase()
+}
+
+fn column_types_from_metadata(metadata: &tiberius::ResultMetadata) -> Vec<String> {
+    metadata.columns().iter().map(sqlserver_column_type_name).collect()
+}
+
 async fn collect_first_result_limited(
     mut stream: QueryStream<'_>,
     start: Instant,
@@ -105,6 +116,7 @@ async fn collect_first_result_limited(
 ) -> Result<QueryResult, String> {
     let row_limit = query_result_row_limit(max_rows);
     let mut columns: Vec<String> = vec![];
+    let mut column_types: Vec<String> = vec![];
     let mut rows: Vec<Vec<serde_json::Value>> = Vec::new();
     let mut truncated = false;
 
@@ -112,6 +124,7 @@ async fn collect_first_result_limited(
         match item {
             QueryItem::Metadata(metadata) if metadata.result_index() == 0 => {
                 columns = columns_from_metadata(&metadata);
+                column_types = column_types_from_metadata(&metadata);
             }
             QueryItem::Metadata(_) => {}
             QueryItem::Row(row) if row.result_index() == 0 => {
@@ -127,6 +140,7 @@ async fn collect_first_result_limited(
 
     Ok(QueryResult {
         columns,
+        column_types,
         rows,
         affected_rows: 0,
         execution_time_ms: start.elapsed().as_millis(),
@@ -138,6 +152,7 @@ async fn collect_first_result_limited(
 
 struct SqlServerResultSet {
     columns: Vec<String>,
+    column_types: Vec<String>,
     rows: Vec<Vec<serde_json::Value>>,
     truncated: bool,
 }
@@ -467,6 +482,7 @@ fn push_sqlserver_result_set(results: &mut Vec<QueryResult>, result: Option<SqlS
         }
         results.push(QueryResult {
             columns: result.columns,
+            column_types: result.column_types,
             rows: result.rows,
             affected_rows: 0,
             execution_time_ms: start.elapsed().as_millis(),
@@ -492,6 +508,7 @@ async fn collect_result_sets_limited(
                 push_sqlserver_result_set(&mut results, current.take(), start);
                 current = Some(SqlServerResultSet {
                     columns: columns_from_metadata(&metadata),
+                    column_types: column_types_from_metadata(&metadata),
                     rows: Vec::new(),
                     truncated: false,
                 });
@@ -499,6 +516,7 @@ async fn collect_result_sets_limited(
             QueryItem::Row(row) => {
                 let result = current.get_or_insert_with(|| SqlServerResultSet {
                     columns: row.columns().iter().map(|c| c.name().to_string()).collect(),
+                    column_types: row.columns().iter().map(sqlserver_column_type_name).collect(),
                     rows: Vec::new(),
                     truncated: false,
                 });
@@ -922,6 +940,7 @@ pub async fn execute_query_with_max_rows(
         let _ = sqlserver_driver_result(collect_result_sets_limited(stream, start, max_rows)).await?;
         Ok(QueryResult {
             columns: vec![],
+            column_types: Vec::new(),
             rows: vec![],
             affected_rows: 0,
             execution_time_ms: start.elapsed().as_millis(),
@@ -933,6 +952,7 @@ pub async fn execute_query_with_max_rows(
         let result = sqlserver_driver_result(client.execute(sql, &[])).await?;
         Ok(QueryResult {
             columns: vec![],
+            column_types: Vec::new(),
             rows: vec![],
             affected_rows: result.rows_affected().iter().sum::<u64>(),
             execution_time_ms: start.elapsed().as_millis(),
@@ -967,6 +987,7 @@ pub async fn execute_batch_with_max_rows(
     if results.is_empty() {
         results.push(QueryResult {
             columns: vec![],
+            column_types: Vec::new(),
             rows: vec![],
             affected_rows: 0,
             execution_time_ms: start.elapsed().as_millis(),
@@ -1262,6 +1283,7 @@ mod tests {
             &mut results,
             Some(SqlServerResultSet {
                 columns: vec!["id".to_string(), "name".to_string()],
+                column_types: vec![],
                 rows: vec![],
                 truncated: false,
             }),
@@ -1278,7 +1300,7 @@ mod tests {
         let mut results = Vec::new();
         super::push_sqlserver_result_set(
             &mut results,
-            Some(SqlServerResultSet { columns: vec![], rows: vec![], truncated: false }),
+            Some(SqlServerResultSet { columns: vec![], column_types: vec![], rows: vec![], truncated: false }),
             Instant::now(),
         );
 
diff --git a/crates/dbx-core/src/query.rs b/crates/dbx-core/src/query.rs
index 20a6eb1b0..d4814fcb6 100644
--- a/crates/dbx-core/src/query.rs
+++ b/crates/dbx-core/src/query.rs
@@ -234,6 +234,7 @@ pub fn duckdb_execute_with_max_rows(
         }
         Ok(db::QueryResult {
             columns,
+            column_types: Vec::new(),
             rows: result_rows,
             affected_rows: 0,
             execution_time_ms: start.elapsed().as_millis(),
@@ -245,6 +246,7 @@ pub fn duckdb_execute_with_max_rows(
         let affected = con.execute(sql, []).map_err(|e| e.to_string())?;
         Ok(db::QueryResult {
             columns: vec![],
+            column_types: Vec::new(),
             rows: vec![],
             affected_rows: affected as u64,
             execution_time_ms: start.elapsed().as_millis(),
@@ -948,6 +950,7 @@ async fn execute_multi_mysql(
 fn error_query_result(message: String) -> db::QueryResult {
     db::QueryResult {
         columns: vec!["Error".to_string()],
+        column_types: Vec::new(),
         rows: vec![vec![serde_json::Value::String(message)]],
         affected_rows: 0,
         execution_time_ms: 0,
@@ -972,6 +975,7 @@ async fn execute_multi_sqlserver(
         if is_canceled(&cancel_token) {
             all_results.push(db::QueryResult {
                 columns: vec!["Error".to_string()],
+                column_types: Vec::new(),
                 rows: vec![vec![serde_json::Value::String(canceled_error())]],
                 affected_rows: 0,
                 execution_time_ms: 0,
@@ -1004,6 +1008,7 @@ async fn execute_multi_sqlserver(
             Err(e) => {
                 all_results.push(db::QueryResult {
                     columns: vec!["Error".to_string()],
+                    column_types: Vec::new(),
                     rows: vec![vec![serde_json::Value::String(e)]],
                     affected_rows: 0,
                     execution_time_ms: 0,
@@ -1018,6 +1023,7 @@ async fn execute_multi_sqlserver(
     if all_results.is_empty() {
         all_results.push(db::QueryResult {
             columns: vec![],
+            column_types: Vec::new(),
             rows: vec![],
             affected_rows: 0,
             execution_time_ms: 0,
@@ -1081,6 +1087,7 @@ pub async fn execute_statements(
 
     Ok(db::QueryResult {
         columns: vec![],
+        column_types: Vec::new(),
         rows: vec![],
         affected_rows: total_affected,
         execution_time_ms: start.elapsed().as_millis(),
@@ -1183,6 +1190,7 @@ async fn exec_tx_pg_inner(
     match tx_result {
         Ok(total_affected) => Ok(db::QueryResult {
             columns: vec![],
+            column_types: Vec::new(),
             rows: vec![],
             affected_rows: total_affected,
             execution_time_ms: start.elapsed().as_millis(),
@@ -1230,6 +1238,7 @@ async fn exec_tx_mysql_inner(
     conn.query_drop("COMMIT").await.map_err(|e| format!("COMMIT failed: {}", e))?;
     Ok(db::QueryResult {
         columns: vec![],
+        column_types: Vec::new(),
         rows: vec![],
         affected_rows: total_affected,
         execution_time_ms: start.elapsed().as_millis(),
@@ -1261,6 +1270,7 @@ async fn exec_tx_sqlite_inner(
             conn.execute_batch("COMMIT").map_err(|e| format!("COMMIT failed: {}", e))?;
             Ok(db::QueryResult {
                 columns: vec![],
+                column_types: Vec::new(),
                 rows: vec![],
                 affected_rows: total_affected,
                 execution_time_ms: start.elapsed().as_millis(),
@@ -1340,6 +1350,7 @@ async fn exec_tx_explicit_inner(
 
     Ok(db::QueryResult {
         columns: vec![],
+        column_types: Vec::new(),
         rows: vec![],
         affected_rows: total_affected,
         execution_time_ms: start.elapsed().as_millis(),
@@ -1381,6 +1392,7 @@ async fn exec_tx_none_inner(
 
     Ok(db::QueryResult {
         columns: vec![],
+        column_types: Vec::new(),
         rows: vec![],
         affected_rows: total_affected,
         execution_time_ms: start.elapsed().as_millis(),
@@ -1404,6 +1416,7 @@ mod tests {
             tokio::time::sleep(Duration::from_secs(30)).await;
             Ok(db::QueryResult {
                 columns: vec![],
+                column_types: Vec::new(),
                 rows: vec![],
                 affected_rows: 0,
                 execution_time_ms: 0,
@@ -1423,6 +1436,7 @@ mod tests {
             tokio::time::sleep(Duration::from_secs(1)).await;
             Ok(db::QueryResult {
                 columns: vec![],
+                column_types: Vec::new(),
                 rows: vec![],
                 affected_rows: 0,
                 execution_time_ms: 0,
@@ -1721,6 +1735,7 @@ mod tests {
     fn query_results_convert_unsafe_json_integers_to_strings_for_js() {
         let result = db::QueryResult {
             columns: vec!["id".to_string(), "nested".to_string()],
+            column_types: Vec::new(),
             rows: vec![vec![
                 serde_json::json!(2_041_797_190_226_354_178_i64),
                 serde_json::json!([1, 2_041_797_190_226_354_178_i64]),
diff --git a/crates/dbx-core/src/transfer.rs b/crates/dbx-core/src/transfer.rs
index 0a23611e8..7ae2be559 100644
--- a/crates/dbx-core/src/transfer.rs
+++ b/crates/dbx-core/src/transfer.rs
@@ -1712,6 +1712,7 @@ pub async fn execute_on_pool_with_max_rows(
                     }
                     Ok(db::QueryResult {
                         columns,
+                        column_types: Vec::new(),
                         rows: result_rows,
                         affected_rows: 0,
                         execution_time_ms: start.elapsed().as_millis(),
@@ -1723,6 +1724,7 @@ pub async fn execute_on_pool_with_max_rows(
                     let affected = con.execute(&sql, []).map_err(|e| e.to_string())?;
                     Ok(db::QueryResult {
                         columns: vec![],
+                        column_types: Vec::new(),
                         rows: vec![],
                         affected_rows: affected as u64,
                         execution_time_ms: start.elapsed().as_millis(),
diff --git a/crates/dbx-core/src/types.rs b/crates/dbx-core/src/types.rs
index b6accfbf7..9d71dee2e 100644
--- a/crates/dbx-core/src/types.rs
+++ b/crates/dbx-core/src/types.rs
@@ -61,6 +61,11 @@ pub struct ColumnInfo {
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct QueryResult {
     pub columns: Vec<String>,
+    /// Database type name for each column, parallel to `columns`. May be empty
+    /// when a driver cannot supply types (e.g. schemaless stores or fallback
+    /// query paths); consumers must tolerate a shorter/empty vector.
+    #[serde(default)]
+    pub column_types: Vec<String>,
     pub rows: Vec<Vec<serde_json::Value>>,
     pub affected_rows: u64,
     pub execution_time_ms: u128,
diff --git a/packages/app-tests/dataGridColumnType.test.ts b/packages/app-tests/dataGridColumnType.test.ts
new file mode 100644
index 000000000..8ff549769
--- /dev/null
+++ b/packages/app-tests/dataGridColumnType.test.ts
@@ -0,0 +1,58 @@
+import { strict as assert } from "node:assert";
+import test from "node:test";
+import { resolveHeaderColumnType } from "../../apps/desktop/src/lib/dataGridColumnType.ts";
+
+test("prefers table-metadata type over the result type", () => {
+  const type = resolveHeaderColumnType({
+    tableColumnType: "numeric(20,6)",
+    resultColumnTypes: ["int4"],
+    actualColIdx: 0,
+  });
+  assert.equal(type, "numeric(20,6)");
+});
+
+test("falls back to the result type at the column index when no table meta", () => {
+  const type = resolveHeaderColumnType({
+    tableColumnType: undefined,
+    resultColumnTypes: ["oid", "char", "bigint"],
+    actualColIdx: 1,
+  });
+  assert.equal(type, "char");
+});
+
+test("uses actualColIdx (by index), not column order assumptions", () => {
+  // The third result column should resolve to the third type, regardless of
+  // any name-based reordering elsewhere.
+  const type = resolveHeaderColumnType({
+    resultColumnTypes: ["a_type", "b_type", "c_type"],
+    actualColIdx: 2,
+  });
+  assert.equal(type, "c_type");
+});
+
+test("returns undefined when the result type index is out of range", () => {
+  const type = resolveHeaderColumnType({
+    resultColumnTypes: ["int4"],
+    actualColIdx: 5,
+  });
+  assert.equal(type, undefined);
+});
+
+test("returns undefined when neither source has a type", () => {
+  assert.equal(resolveHeaderColumnType({ actualColIdx: 0 }), undefined);
+  assert.equal(resolveHeaderColumnType({ resultColumnTypes: [], actualColIdx: 0 }), undefined);
+});
+
+test("treats blank/whitespace types as absent and falls through", () => {
+  const type = resolveHeaderColumnType({
+    tableColumnType: "   ",
+    resultColumnTypes: ["text"],
+    actualColIdx: 0,
+  });
+  assert.equal(type, "text");
+
+  assert.equal(
+    resolveHeaderColumnType({ tableColumnType: "", resultColumnTypes: [""], actualColIdx: 0 }),
+    undefined,
+  );
+});