fix(core): preserve JSON literals in copied INSERT statements

crates/dbx-core/src/data_grid_sql.rs

@@ -1724,6 +1724,20 @@ fn format_grid_copy_insert_sql_literal(
             }
         }
     }
+    // JSON columns may expose a JSON array/object value (e.g. `[1,2,3]` or `{}`)
+    // instead of its string form. Keep it as a single JSON literal rather than
+    // letting format_grid_sql_literal serialize it as a PostgreSQL-style array
+    // (`{...}`). Serialize the value back to compact JSON text, format that as a
+    // string literal, then cast it for MySQL so it inserts as JSON.
+    if column_info.is_some_and(|column| {
+        let dt = column.data_type.trim();
+        dt.eq_ignore_ascii_case("json") || dt.eq_ignore_ascii_case("jsonb")
+    }) && (value.is_array() || value.is_object())
+    {
+        let json_text = value.to_string();
+        let string_literal = format_grid_sql_literal(&Value::String(json_text), database_type, column_info);
+        return mysql_json_predicate_literal(string_literal, database_type, column_info);
+    }
     format_grid_sql_literal(value, database_type, column_info)
 }
 
@@ -2990,6 +3004,57 @@ mod tests {
         );
     }
 
+    #[test]
+    fn copy_insert_keeps_mysql_json_array_as_single_json_literal() {
+        let statement = build_data_grid_copy_insert_statement(DataGridCopyInsertStatementOptions {
+            database_type: Some(DatabaseType::Mysql),
+            table_meta: None,
+            columns: vec!["data".to_string()],
+            column_types: Some(vec![Some("json".to_string())]),
+            source_columns: None,
+            rows: vec![vec![json!([1, 2, 3])]],
+            exclude_primary_keys: false,
+            include_computed_columns: false,
+            insert_mode: DataGridCopyInsertMode::Merged,
+        });
+
+        assert_eq!(statement.as_deref(), Some("INSERT INTO table_name (`data`) VALUES (CAST('[1,2,3]' AS JSON));"));
+    }
+
+    #[test]
+    fn copy_insert_keeps_mysql_json_empty_array_as_single_json_literal() {
+        let statement = build_data_grid_copy_insert_statement(DataGridCopyInsertStatementOptions {
+            database_type: Some(DatabaseType::Mysql),
+            table_meta: None,
+            columns: vec!["data".to_string()],
+            column_types: Some(vec![Some("json".to_string())]),
+            source_columns: None,
+            rows: vec![vec![json!([])]],
+            exclude_primary_keys: false,
+            include_computed_columns: false,
+            insert_mode: DataGridCopyInsertMode::Merged,
+        });
+
+        assert_eq!(statement.as_deref(), Some("INSERT INTO table_name (`data`) VALUES (CAST('[]' AS JSON));"));
+    }
+
+    #[test]
+    fn copy_insert_keeps_mysql_json_object_as_single_json_literal() {
+        let statement = build_data_grid_copy_insert_statement(DataGridCopyInsertStatementOptions {
+            database_type: Some(DatabaseType::Mysql),
+            table_meta: None,
+            columns: vec!["data".to_string()],
+            column_types: Some(vec![Some("json".to_string())]),
+            source_columns: None,
+            rows: vec![vec![json!({"a": 1})]],
+            exclude_primary_keys: false,
+            include_computed_columns: false,
+            insert_mode: DataGridCopyInsertMode::Merged,
+        });
+
+        assert_eq!(statement.as_deref(), Some("INSERT INTO table_name (`data`) VALUES (CAST('{\"a\":1}' AS JSON));"));
+    }
+
     #[test]
     fn builds_copy_insert_without_primary_keys_when_primary_keys_are_hidden() {
         let statement = build_data_grid_copy_insert_statement(DataGridCopyInsertStatementOptions {