diff --git a/apps/desktop/src/components/config/ConfigPassphraseDialog.vue b/apps/desktop/src/components/config/ConfigPassphraseDialog.vue
index 88d99e237..10445254b 100644
--- a/apps/desktop/src/components/config/ConfigPassphraseDialog.vue
+++ b/apps/desktop/src/components/config/ConfigPassphraseDialog.vue
@@ -28,13 +28,17 @@ const passphrase = ref("");
 const passphraseConfirm = ref("");
 const error = ref("");
 
-watch(dialogOpen, (open) => {
-  if (open) {
-    passphrase.value = "";
-    passphraseConfirm.value = "";
-    error.value = "";
-  }
-});
+watch(
+  dialogOpen,
+  (open) => {
+    if (open) {
+      passphrase.value = "";
+      passphraseConfirm.value = "";
+      error.value = "";
+    }
+  },
+  { immediate: true },
+);
 
 function confirm() {
   if (!passphrase.value) {
diff --git a/apps/desktop/src/components/connection/ConnectionDialog.vue b/apps/desktop/src/components/connection/ConnectionDialog.vue
index 4f755a578..51138634a 100644
--- a/apps/desktop/src/components/connection/ConnectionDialog.vue
+++ b/apps/desktop/src/components/connection/ConnectionDialog.vue
@@ -667,17 +667,21 @@ function resetForm() {
   resetTestState();
 }
 
-watch(open, (value) => {
-  if (!value) {
-    resetForm();
-    return;
-  }
-  if (!props.editConfig) {
-    resetForm();
-  }
-  void loadJdbcDrivers();
-  void loadAgentDrivers();
-});
+watch(
+  open,
+  (value) => {
+    if (!value) {
+      resetForm();
+      return;
+    }
+    if (!props.editConfig) {
+      resetForm();
+    }
+    void loadJdbcDrivers();
+    void loadAgentDrivers();
+  },
+  { immediate: true },
+);
 
 watch(canUseSsh, (value) => {
   if (!value && configTab.value === "ssh") {
diff --git a/apps/desktop/src/components/diagram/SchemaDiagramDialog.vue b/apps/desktop/src/components/diagram/SchemaDiagramDialog.vue
index f4343ba67..a7ff39429 100644
--- a/apps/desktop/src/components/diagram/SchemaDiagramDialog.vue
+++ b/apps/desktop/src/components/diagram/SchemaDiagramDialog.vue
@@ -661,9 +661,13 @@ function stopDrag() {
   window.removeEventListener("mouseup", stopDrag);
 }
 
-watch(open, (value) => {
-  if (value) void initialize();
-});
+watch(
+  open,
+  (value) => {
+    if (value) void initialize();
+  },
+  { immediate: true },
+);
 
 watch(
   () => visibleTables.value.map((table) => table.name).join("\n"),
diff --git a/apps/desktop/src/components/diff/DataCompareDialog.vue b/apps/desktop/src/components/diff/DataCompareDialog.vue
index 57f203517..28718749c 100644
--- a/apps/desktop/src/components/diff/DataCompareDialog.vue
+++ b/apps/desktop/src/components/diff/DataCompareDialog.vue
@@ -412,21 +412,25 @@ watch(sourceTable, (table, previous) => {
   }
 });
 watch(targetTable, () => clearResult());
-watch(open, async (value) => {
-  if (!value) return;
-  result.value = null;
-  syncSql.value = "";
-  if (props.prefillConnectionId) {
-    sourceConnectionId.value = props.prefillConnectionId;
-    await loadDatabases(props.prefillConnectionId, "source");
-    if (props.prefillDatabase) sourceDatabase.value = props.prefillDatabase;
-    if (props.prefillDatabase) await loadSchemas("source", props.prefillSchema);
-    if (props.prefillTable) {
-      await loadTables("source");
-      if (sourceTables.value.includes(props.prefillTable)) sourceTable.value = props.prefillTable;
+watch(
+  open,
+  async (value) => {
+    if (!value) return;
+    result.value = null;
+    syncSql.value = "";
+    if (props.prefillConnectionId) {
+      sourceConnectionId.value = props.prefillConnectionId;
+      await loadDatabases(props.prefillConnectionId, "source");
+      if (props.prefillDatabase) sourceDatabase.value = props.prefillDatabase;
+      if (props.prefillDatabase) await loadSchemas("source", props.prefillSchema);
+      if (props.prefillTable) {
+        await loadTables("source");
+        if (sourceTables.value.includes(props.prefillTable)) sourceTable.value = props.prefillTable;
+      }
     }
-  }
-});
+  },
+  { immediate: true },
+);
 </script>
 
 <template>
diff --git a/apps/desktop/src/components/diff/SchemaDiffDialog.vue b/apps/desktop/src/components/diff/SchemaDiffDialog.vue
index a11d06d71..40bb5a882 100644
--- a/apps/desktop/src/components/diff/SchemaDiffDialog.vue
+++ b/apps/desktop/src/components/diff/SchemaDiffDialog.vue
@@ -356,23 +356,27 @@ watch(targetDatabase, (database) => {
 watch(sourceSchema, () => resetResult());
 watch(targetSchema, () => resetResult());
 
-watch(open, async (val) => {
-  if (val) {
-    step.value = "select";
-    diffs.value = [];
-    syncErrors.value = [];
-    executedCount.value = 0;
-    executeTotal.value = 0;
-    if (props.prefillConnectionId) {
-      sourceConnectionId.value = props.prefillConnectionId;
-      await loadDatabases(props.prefillConnectionId, "source");
-      if (props.prefillDatabase) {
-        sourceDatabase.value = props.prefillDatabase;
-        await loadSchemas("source", props.prefillSchema);
+watch(
+  open,
+  async (val) => {
+    if (val) {
+      step.value = "select";
+      diffs.value = [];
+      syncErrors.value = [];
+      executedCount.value = 0;
+      executeTotal.value = 0;
+      if (props.prefillConnectionId) {
+        sourceConnectionId.value = props.prefillConnectionId;
+        await loadDatabases(props.prefillConnectionId, "source");
+        if (props.prefillDatabase) {
+          sourceDatabase.value = props.prefillDatabase;
+          await loadSchemas("source", props.prefillSchema);
+        }
       }
     }
-  }
-});
+  },
+  { immediate: true },
+);
 </script>
 
 <template>
diff --git a/apps/desktop/src/components/export/DatabaseExportDialog.vue b/apps/desktop/src/components/export/DatabaseExportDialog.vue
index c00f662d3..8f45e5577 100644
--- a/apps/desktop/src/components/export/DatabaseExportDialog.vue
+++ b/apps/desktop/src/components/export/DatabaseExportDialog.vue
@@ -292,21 +292,25 @@ watch(schema, (value) => {
   if (value) loadTables(preferredTable).catch((e) => toast(String(e), 5000));
 });
 
-watch(open, async (val) => {
-  if (val) {
-    resetState();
-    pendingPrefillTable.value = props.prefillTable ?? "";
-    if (props.prefillConnectionId) {
-      skipConnectionWatch.value = true;
-      connectionId.value = props.prefillConnectionId;
-      await loadDatabases(props.prefillConnectionId);
-      if (props.prefillDatabase) {
-        database.value = props.prefillDatabase;
-        await loadSchemas(props.prefillSchema);
+watch(
+  open,
+  async (val) => {
+    if (val) {
+      resetState();
+      pendingPrefillTable.value = props.prefillTable ?? "";
+      if (props.prefillConnectionId) {
+        skipConnectionWatch.value = true;
+        connectionId.value = props.prefillConnectionId;
+        await loadDatabases(props.prefillConnectionId);
+        if (props.prefillDatabase) {
+          database.value = props.prefillDatabase;
+          await loadSchemas(props.prefillSchema);
+        }
       }
     }
-  }
-});
+  },
+  { immediate: true },
+);
 </script>
 
 <template>
diff --git a/apps/desktop/src/components/import/TableImportDialog.vue b/apps/desktop/src/components/import/TableImportDialog.vue
index 8b1165603..fe276abc4 100644
--- a/apps/desktop/src/components/import/TableImportDialog.vue
+++ b/apps/desktop/src/components/import/TableImportDialog.vue
@@ -231,12 +231,16 @@ async function cancelImport() {
   await api.cancelTableImport(importId.value);
 }
 
-watch(open, (value) => {
-  if (value) {
-    resetState();
-    void loadTargetColumns();
-  }
-});
+watch(
+  open,
+  (value) => {
+    if (value) {
+      resetState();
+      void loadTargetColumns();
+    }
+  },
+  { immediate: true },
+);
 </script>
 
 <template>
diff --git a/apps/desktop/src/components/lineage/FieldLineageDialog.vue b/apps/desktop/src/components/lineage/FieldLineageDialog.vue
index a66ea04ca..6cdee6834 100644
--- a/apps/desktop/src/components/lineage/FieldLineageDialog.vue
+++ b/apps/desktop/src/components/lineage/FieldLineageDialog.vue
@@ -119,15 +119,19 @@ const filteredItems = computed(() => {
 
 const filteredCounts = computed(() => summarizeLineageCounts(filteredItems.value));
 
-watch(dialogOpen, (open) => {
-  if (open) {
-    confidenceFilter.value = "all";
-    searchText.value = "";
-    void loadLineage();
-  } else {
-    cancelLoad();
-  }
-});
+watch(
+  dialogOpen,
+  (open) => {
+    if (open) {
+      confidenceFilter.value = "all";
+      searchText.value = "";
+      void loadLineage();
+    } else {
+      cancelLoad();
+    }
+  },
+  { immediate: true },
+);
 
 function cancelLoad() {
   cancelled.value = true;
diff --git a/apps/desktop/src/components/search/DatabaseSearchDialog.vue b/apps/desktop/src/components/search/DatabaseSearchDialog.vue
index 53fe63449..451bcb261 100644
--- a/apps/desktop/src/components/search/DatabaseSearchDialog.vue
+++ b/apps/desktop/src/components/search/DatabaseSearchDialog.vue
@@ -95,13 +95,17 @@ const progressLabel = computed(() =>
   t("databaseSearch.progress", { done: progressDone.value, total: progressTotal.value }),
 );
 
-watch(dialogOpen, (open) => {
-  if (open) {
-    resetSearchState();
-  } else {
-    stopSearch();
-  }
-});
+watch(
+  dialogOpen,
+  (open) => {
+    if (open) {
+      resetSearchState();
+    } else {
+      stopSearch();
+    }
+  },
+  { immediate: true },
+);
 
 function resetSearchState() {
   running.value = false;
diff --git a/apps/desktop/src/components/sql-file/SqlFileExecutionDialog.vue b/apps/desktop/src/components/sql-file/SqlFileExecutionDialog.vue
index 76f671b50..758f041a6 100644
--- a/apps/desktop/src/components/sql-file/SqlFileExecutionDialog.vue
+++ b/apps/desktop/src/components/sql-file/SqlFileExecutionDialog.vue
@@ -376,13 +376,17 @@ watch(sqlConnections, () => {
   connectionId.value = resolveInitialConnectionId();
 });
 
-watch(open, (value) => {
-  if (!value) return;
-  resetState();
-  if (connectionId.value) {
-    loadDatabasesForConnection(connectionId.value);
-  }
-});
+watch(
+  open,
+  (value) => {
+    if (!value) return;
+    resetState();
+    if (connectionId.value) {
+      loadDatabasesForConnection(connectionId.value);
+    }
+  },
+  { immediate: true },
+);
 </script>
 
 <template>
diff --git a/apps/desktop/src/components/transfer/DataTransferDialog.vue b/apps/desktop/src/components/transfer/DataTransferDialog.vue
index c207ac079..50d4d3b34 100644
--- a/apps/desktop/src/components/transfer/DataTransferDialog.vue
+++ b/apps/desktop/src/components/transfer/DataTransferDialog.vue
@@ -159,19 +159,23 @@ watch(targetConnectionId, (id) => {
   loadDatabases(id, "target");
 });
 
-watch(open, async (val) => {
-  if (val) {
-    resetState();
-    if (props.prefillConnectionId) {
-      skipSourceWatch.value = true;
-      sourceConnectionId.value = props.prefillConnectionId;
-      await loadDatabases(props.prefillConnectionId, "source");
-      if (props.prefillDatabase) {
-        sourceDatabase.value = props.prefillDatabase;
+watch(
+  open,
+  async (val) => {
+    if (val) {
+      resetState();
+      if (props.prefillConnectionId) {
+        skipSourceWatch.value = true;
+        sourceConnectionId.value = props.prefillConnectionId;
+        await loadDatabases(props.prefillConnectionId, "source");
+        if (props.prefillDatabase) {
+          sourceDatabase.value = props.prefillDatabase;
+        }
       }
     }
-  }
-});
+  },
+  { immediate: true },
+);
 
 function resetState() {
   sourceConnectionId.value = "";
diff --git a/apps/desktop/src/lib/tableStructureCapabilities.ts b/apps/desktop/src/lib/tableStructureCapabilities.ts
index 8c5635ecb..22fbec3a0 100644
--- a/apps/desktop/src/lib/tableStructureCapabilities.ts
+++ b/apps/desktop/src/lib/tableStructureCapabilities.ts
@@ -167,6 +167,12 @@ const clickhouseCapabilities = capabilities({
   createTable: true,
   addColumn: true,
   dropColumn: true,
+  renameColumn: true,
+  alterExistingColumn: true,
+  alterType: true,
+  alterNullability: true,
+  alterDefault: true,
+  comment: true,
 });
 
 const capabilityByType: Partial<Record<DatabaseType, TableStructureCapabilities>> = {
diff --git a/apps/desktop/src/lib/tableStructureEditorSql.ts b/apps/desktop/src/lib/tableStructureEditorSql.ts
index c6ec4ce1f..2b03da876 100644
--- a/apps/desktop/src/lib/tableStructureEditorSql.ts
+++ b/apps/desktop/src/lib/tableStructureEditorSql.ts
@@ -85,9 +85,23 @@ function normalizeDefault(value: string | null | undefined): string {
   return trimmed.toLowerCase() === "null" ? "" : trimmed;
 }
 
+function unwrapClickHouseNullableType(dataType: string): string {
+  const match = dataType.trim().match(/^Nullable\s*\((.*)\)$/is);
+  return match ? match[1].trim() : dataType.trim();
+}
+
+function clickHouseColumnType(column: EditableStructureColumn): string {
+  const dataType = column.dataType.trim();
+  if (column.isNullable) {
+    return /^Nullable\s*\(/i.test(dataType) ? dataType : `Nullable(${dataType})`;
+  }
+  return unwrapClickHouseNullableType(dataType);
+}
+
 function columnDefinition(databaseType: StructureSqlFlavor, column: EditableStructureColumn): string {
-  const parts = [quoteIdent(databaseType, column.name), column.dataType.trim()];
-  if (!column.isNullable && !isOracleLike(databaseType)) parts.push("NOT NULL");
+  const dataType = databaseType === "clickhouse" ? clickHouseColumnType(column) : column.dataType.trim();
+  const parts = [quoteIdent(databaseType, column.name), dataType];
+  if (!column.isNullable && !isOracleLike(databaseType) && databaseType !== "clickhouse") parts.push("NOT NULL");
   const defaultValue = normalizeDefault(column.defaultValue);
   if (defaultValue) parts.push(`DEFAULT ${defaultValue}`);
   if (databaseType === "mysql" && clean(column.comment)) {
@@ -127,6 +141,11 @@ function buildAddColumnSql(databaseType: StructureSqlFlavor, table: string, colu
       `COMMENT ON COLUMN ${table}.${quoteIdent(databaseType, column.name)} IS ${quoteString(clean(column.comment))};`,
     );
   }
+  if (databaseType === "clickhouse" && clean(column.comment)) {
+    statements.push(
+      `ALTER TABLE ${table} COMMENT COLUMN ${quoteIdent(databaseType, column.name)} ${quoteString(clean(column.comment))};`,
+    );
+  }
   return statements;
 }
 
@@ -240,6 +259,48 @@ function buildH2ExistingColumnSql(table: string, column: EditableStructureColumn
   return statements;
 }
 
+function buildClickHouseExistingColumnSql(table: string, column: EditableStructureColumn): string[] {
+  const original = column.original;
+  if (!original) return [];
+
+  const statements: string[] = [];
+  let currentName = original.name;
+  if (column.name !== original.name) {
+    statements.push(
+      `ALTER TABLE ${table} RENAME COLUMN ${quoteIdent("clickhouse", original.name)} TO ${quoteIdent("clickhouse", column.name)};`,
+    );
+    currentName = column.name;
+  }
+  if (
+    clickHouseColumnType(column) !== original.data_type.trim() ||
+    normalizeDefault(column.defaultValue) !== originalDefault(column)
+  ) {
+    const defaultValue = normalizeDefault(column.defaultValue);
+    if (defaultValue) {
+      statements.push(
+        `ALTER TABLE ${table} MODIFY COLUMN ${quoteIdent("clickhouse", currentName)} ${clickHouseColumnType(column)} DEFAULT ${defaultValue};`,
+      );
+    } else if (originalDefault(column)) {
+      statements.push(`ALTER TABLE ${table} MODIFY COLUMN ${quoteIdent("clickhouse", currentName)} REMOVE DEFAULT;`);
+      if (clickHouseColumnType(column) !== original.data_type.trim()) {
+        statements.push(
+          `ALTER TABLE ${table} MODIFY COLUMN ${quoteIdent("clickhouse", currentName)} ${clickHouseColumnType(column)};`,
+        );
+      }
+    } else {
+      statements.push(
+        `ALTER TABLE ${table} MODIFY COLUMN ${quoteIdent("clickhouse", currentName)} ${clickHouseColumnType(column)};`,
+      );
+    }
+  }
+  if (clean(column.comment) !== originalComment(column)) {
+    statements.push(
+      `ALTER TABLE ${table} COMMENT COLUMN ${quoteIdent("clickhouse", currentName)} ${quoteString(clean(column.comment))};`,
+    );
+  }
+  return statements;
+}
+
 function buildSqliteExistingColumnSql(table: string, column: EditableStructureColumn, warnings: string[]): string[] {
   const original = column.original;
   if (!original) return [];
@@ -321,6 +382,8 @@ function buildColumnSql(options: BuildTableStructureChangeSqlOptions, warnings:
       statements.push(...buildOracleLikeExistingColumnSql(dialect, table, column));
     } else if (dialect === "h2") {
       statements.push(...buildH2ExistingColumnSql(table, column));
+    } else if (dialect === "clickhouse") {
+      statements.push(...buildClickHouseExistingColumnSql(table, column));
     } else if (dialect === "sqlite") {
       statements.push(...buildSqliteExistingColumnSql(table, column, warnings));
     } else {
@@ -463,8 +526,9 @@ export function buildCreateTableSql(options: BuildTableStructureChangeSqlOptions
 
   const pkColumns = activeColumns.filter((c) => c.isPrimaryKey);
   const colDefs = activeColumns.map((col) => {
-    const parts = [quoteIdent(dialect, col.name), col.dataType.trim()];
-    if (!col.isNullable && !col.isPrimaryKey) parts.push("NOT NULL");
+    const dataType = dialect === "clickhouse" ? clickHouseColumnType(col) : col.dataType.trim();
+    const parts = [quoteIdent(dialect, col.name), dataType];
+    if (!col.isNullable && !col.isPrimaryKey && dialect !== "clickhouse") parts.push("NOT NULL");
     const defaultValue = normalizeDefault(col.defaultValue);
     if (defaultValue) parts.push(`DEFAULT ${defaultValue}`);
     if (dialect === "mysql" && capabilities.comment && clean(col.comment)) {
@@ -489,6 +553,15 @@ export function buildCreateTableSql(options: BuildTableStructureChangeSqlOptions
       }
     }
   }
+  if (capabilities.comment && dialect === "clickhouse") {
+    for (const col of activeColumns) {
+      if (clean(col.comment)) {
+        statements.push(
+          `ALTER TABLE ${table} COMMENT COLUMN ${quoteIdent(dialect, col.name)} ${quoteString(clean(col.comment))};`,
+        );
+      }
+    }
+  }
 
   for (const index of options.indexes.filter((idx) => !idx.markedForDrop && !idx.isPrimary)) {
     const name = clean(index.name);
diff --git a/crates/dbx-core/src/db/clickhouse_driver.rs b/crates/dbx-core/src/db/clickhouse_driver.rs
index 7e2bcb989..6ef09ce3c 100644
--- a/crates/dbx-core/src/db/clickhouse_driver.rs
+++ b/crates/dbx-core/src/db/clickhouse_driver.rs
@@ -160,7 +160,7 @@ pub async fn list_tables(client: &ChClient, database: &str) -> Result<Vec<TableI
 
 pub async fn get_columns(client: &ChClient, database: &str, table: &str) -> Result<Vec<ColumnInfo>, String> {
     let sql = format!(
-        "SELECT name, type, default_kind, default_expression, is_in_primary_key \
+        "SELECT name, type, default_kind, default_expression, is_in_primary_key, comment \
          FROM system.columns WHERE database = '{}' AND table = '{}' ORDER BY position",
         database.replace('\'', "\\'"),
         table.replace('\'', "\\'")
@@ -183,7 +183,7 @@ pub async fn get_columns(client: &ChClient, database: &str, table: &str) -> Resu
                 column_default,
                 is_primary_key: is_pk,
                 extra: None,
-                comment: None,
+                comment: row.get(5).and_then(|v| v.as_str()).filter(|value| !value.is_empty()).map(str::to_string),
                 numeric_precision: None,
                 numeric_scale: None,
                 character_maximum_length: None,
diff --git a/packages/app-tests/dialogOpenWatcher.test.ts b/packages/app-tests/dialogOpenWatcher.test.ts
new file mode 100644
index 000000000..3037b1d4e
--- /dev/null
+++ b/packages/app-tests/dialogOpenWatcher.test.ts
@@ -0,0 +1,29 @@
+import { readFileSync } from "node:fs";
+import assert from "node:assert/strict";
+import test from "node:test";
+
+const mountedOpenDialogs = [
+  "apps/desktop/src/components/connection/ConnectionDialog.vue",
+  "apps/desktop/src/components/transfer/DataTransferDialog.vue",
+  "apps/desktop/src/components/diff/SchemaDiffDialog.vue",
+  "apps/desktop/src/components/diff/DataCompareDialog.vue",
+  "apps/desktop/src/components/sql-file/SqlFileExecutionDialog.vue",
+  "apps/desktop/src/components/diagram/SchemaDiagramDialog.vue",
+  "apps/desktop/src/components/import/TableImportDialog.vue",
+  "apps/desktop/src/components/structure/TableStructureEditorDialog.vue",
+  "apps/desktop/src/components/lineage/FieldLineageDialog.vue",
+  "apps/desktop/src/components/search/DatabaseSearchDialog.vue",
+  "apps/desktop/src/components/export/DatabaseExportDialog.vue",
+  "apps/desktop/src/components/config/ConfigPassphraseDialog.vue",
+] as const;
+
+test("dialogs initialized through v-if run their open watcher on mount", () => {
+  for (const filePath of mountedOpenDialogs) {
+    const source = readFileSync(filePath, "utf8");
+    assert.match(
+      source,
+      /watch\(\s*(open|dialogOpen),[\s\S]*?\{\s*immediate:\s*true\s*\},?\s*\)/,
+      `${filePath} should use an immediate open watcher`,
+    );
+  }
+});
diff --git a/packages/app-tests/tableStructureCapabilities.test.ts b/packages/app-tests/tableStructureCapabilities.test.ts
index da0c70942..906543fe0 100644
--- a/packages/app-tests/tableStructureCapabilities.test.ts
+++ b/packages/app-tests/tableStructureCapabilities.test.ts
@@ -59,9 +59,12 @@ test("limited analytic engines can open the editor for supported operations only
   assert.equal(clickhouse.createTable, true);
   assert.equal(clickhouse.addColumn, true);
   assert.equal(clickhouse.dropColumn, true);
-  assert.equal(clickhouse.renameColumn, false);
-  assert.equal(clickhouse.alterExistingColumn, false);
-  assert.equal(clickhouse.comment, false);
+  assert.equal(clickhouse.renameColumn, true);
+  assert.equal(clickhouse.alterExistingColumn, true);
+  assert.equal(clickhouse.alterType, true);
+  assert.equal(clickhouse.alterNullability, true);
+  assert.equal(clickhouse.alterDefault, true);
+  assert.equal(clickhouse.comment, true);
   assert.equal(clickhouse.createIndex, false);
   assert.equal(canEditTableStructure("clickhouse"), true);
 });
diff --git a/packages/app-tests/tableStructureEditorPresentation.test.ts b/packages/app-tests/tableStructureEditorPresentation.test.ts
index 227449f53..419c83a61 100644
--- a/packages/app-tests/tableStructureEditorPresentation.test.ts
+++ b/packages/app-tests/tableStructureEditorPresentation.test.ts
@@ -3,6 +3,7 @@ import { strict as assert } from "node:assert";
 import test from "node:test";
 
 const source = readFileSync("apps/desktop/src/components/structure/TableStructureEditorDialog.vue", "utf8");
+const clickhouseSource = readFileSync("crates/dbx-core/src/db/clickhouse_driver.rs", "utf8");
 
 test("column comments can be expanded into a multiline editor", () => {
   assert.match(source, /PopoverContent/);
@@ -18,6 +19,11 @@ test("structure editor keeps columns when optional metadata fails", () => {
   assert.match(source, /api\s*\n\s*\.listTriggers[\s\S]*\.catch\(\(\) => \[\]\)/);
 });
 
+test("ClickHouse column metadata preserves comments for structure editing", () => {
+  assert.match(clickhouseSource, /SELECT name, type, default_kind, default_expression, is_in_primary_key, comment/);
+  assert.match(clickhouseSource, /comment:\s*row\.get\(5\)/);
+});
+
 test("structure editor loads immediately when mounted open", () => {
   assert.match(source, /watch\(\s*open,[\s\S]*\{\s*immediate:\s*true\s*\},?\s*\)/);
 });
diff --git a/packages/app-tests/tableStructureEditorSql.test.ts b/packages/app-tests/tableStructureEditorSql.test.ts
index 22730300b..65573cea2 100644
--- a/packages/app-tests/tableStructureEditorSql.test.ts
+++ b/packages/app-tests/tableStructureEditorSql.test.ts
@@ -657,12 +657,12 @@ test("Redshift skips unsupported index operations while keeping column DDL", ()
   assert.deepEqual(result.warnings, ['Creating indexes is not supported for redshift from this editor.']);
 });
 
-test("builds ClickHouse limited column DDL and skips indexes", () => {
+test("builds ClickHouse column DDL and skips indexes", () => {
   const result = buildTableStructureChangeSql({
     databaseType: "clickhouse",
     tableName: "events",
     columns: [
-      column({ id: "new", name: "name", dataType: "String", isNullable: true }),
+      column({ id: "new", name: "name", dataType: "String", isNullable: false }),
       column({
         id: "legacy",
         name: "legacy",
@@ -679,12 +679,14 @@ test("builds ClickHouse limited column DDL and skips indexes", () => {
       column({
         id: "kind",
         name: "event_kind",
-        dataType: "String",
+        dataType: "LowCardinality(String)",
+        isNullable: false,
+        defaultValue: "'view'",
         original: {
           name: "kind",
           data_type: "String",
-          is_nullable: true,
-          column_default: null,
+          is_nullable: false,
+          column_default: "'click'",
           is_primary_key: false,
           extra: null,
         },
@@ -696,10 +698,52 @@ test("builds ClickHouse limited column DDL and skips indexes", () => {
   assert.deepEqual(result.statements, [
     'ALTER TABLE "events" ADD COLUMN "name" String;',
     'ALTER TABLE "events" DROP COLUMN "legacy";',
+    'ALTER TABLE "events" RENAME COLUMN "kind" TO "event_kind";',
+    'ALTER TABLE "events" MODIFY COLUMN "event_kind" LowCardinality(String) DEFAULT \'view\';',
   ]);
-  assert.deepEqual(result.warnings, [
-    'Renaming columns is not supported for clickhouse from this editor.',
-    'Creating indexes is not supported for clickhouse from this editor.',
+  assert.deepEqual(result.warnings, ['Creating indexes is not supported for clickhouse from this editor.']);
+});
+
+test("builds ClickHouse nullable and comment column changes", () => {
+  const result = buildTableStructureChangeSql({
+    databaseType: "clickhouse",
+    tableName: "events",
+    columns: [
+      column({
+        id: "new",
+        name: "source",
+        dataType: "String",
+        isNullable: true,
+        comment: "traffic source",
+      }),
+      column({
+        id: "status",
+        name: "status",
+        dataType: "Nullable(String)",
+        isNullable: false,
+        defaultValue: "",
+        comment: "current status",
+        original: {
+          name: "status",
+          data_type: "Nullable(String)",
+          is_nullable: true,
+          column_default: "'pending'",
+          is_primary_key: false,
+          extra: null,
+          comment: "old status",
+        },
+      }),
+    ],
+    indexes: [],
+  });
+
+  assert.deepEqual(result.warnings, []);
+  assert.deepEqual(result.statements, [
+    'ALTER TABLE "events" ADD COLUMN "source" Nullable(String);',
+    'ALTER TABLE "events" COMMENT COLUMN "source" \'traffic source\';',
+    'ALTER TABLE "events" MODIFY COLUMN "status" REMOVE DEFAULT;',
+    'ALTER TABLE "events" MODIFY COLUMN "status" String;',
+    'ALTER TABLE "events" COMMENT COLUMN "status" \'current status\';',
   ]);
 });