fix(grid): disambiguate duplicate column names in headers

apps/desktop/src/components/grid/DataGrid.vue

@@ -119,6 +119,7 @@ import { uuid } from "@/lib/common/utils";
 import { generateCellValues, type CellValueGenerationKind, type CellValueGenerationOptions } from "@/lib/dataGrid/cellValueGeneration";
 import { MONGO_DOCUMENT_GRID_NULL, mongoDocumentGridClipboardText, mongoDocumentGridDisplayText, mongoDocumentGridEditorText, mongoDocumentGridExternalValue, mongoDocumentGridInputValue, mongoDocumentGridNumericValue, mongoDocumentRelaxedExtendedJson } from "@/lib/mongo/mongoDocumentValues";
 import { compactHeaderColumnType, formatMetadataColumnTypeLabel, isNumericColumnType, resolveDataGridTypeVisualKind, resolveHeaderColumnType, resolveResultColumnType, shortHeaderTypeName } from "@/lib/dataGrid/dataGridColumnType";
+import { dedupeResultColumnNames } from "@/lib/sql/resultColumnNames";
 import { dataGridCellTextClass, dataGridTypeVisualClass } from "@/lib/dataGrid/dataGridCellTextVisual";
 import { DATA_GRID_TYPE_COLOR_KEYS, resolveActiveDataGridTypeColors } from "@/lib/dataGrid/dataGridTypeColorScheme";
 import {
@@ -2419,6 +2420,10 @@ const filteredGoToColumns = computed(() => {
   return filterDataGridColumnLookupItems(goToColumnItems.value, goToColumnSearch.value, goToColumnMatchMode.value);
 });
 const visibleColumns = computed(() => visibleColumnIndexes.value.map((index) => props.result.columns[index]));
+// Header labels only: SQL generation, sorting, transfer and export keep the raw
+// result columns so duplicate-label handling (#12214) and INSERT targets stay
+// correct. Duplicate labels are disambiguated for display only (#12452).
+const displayColumnNames = computed(() => dedupeResultColumnNames(props.result.columns));
 const visibleColumnIndexIndicators = computed(() =>
   visibleColumns.value.map((column) => {
     if (!showIndexIndicatorsInHeader.value) return false;
@@ -14823,7 +14828,7 @@ useUpdateBlocker(() => (hasPendingChanges.value || hasPendingDataEditorDraft.val
                   <DataGridColumnHeader
                     v-for="col in renderedGridColumns"
                     :key="`${col.name}-${col.actualColIdx}`"
-                    :name="col.name"
+                    :name="displayColumnNames[col.actualColIdx] ?? col.name"
                     :actual-column-index="col.actualColIdx"
                     :visible-column-index="col.visibleColIdx"
                     :class="{ 'crosshair-column': !!crosshairTarget?.columnCrosshair && crosshairTarget.visibleColIdx === col.visibleColIdx }"

apps/desktop/src/lib/__tests__/sql/resultColumnNames.spec.ts

@@ -0,0 +1,17 @@
+import { describe, expect, it } from "vitest";
+import { dedupeResultColumnNames } from "@/lib/sql/resultColumnNames";
+
+describe("dedupeResultColumnNames", () => {
+  it("renames repeated labels with numeric suffixes", () => {
+    expect(dedupeResultColumnNames(["id", "name", "name", "name"])).toEqual(["id", "name", "name_1", "name_2"]);
+  });
+
+  it("never collides with a label that already uses the suffix", () => {
+    expect(dedupeResultColumnNames(["name", "name_1", "name", "name"])).toEqual(["name", "name_1", "name_2", "name_3"]);
+  });
+
+  it("keeps unique and empty labels untouched", () => {
+    expect(dedupeResultColumnNames(["", "a", "b"])).toEqual(["", "a", "b"]);
+    expect(dedupeResultColumnNames([])).toEqual([]);
+  });
+});

apps/desktop/src/lib/sql/resultColumnNames.ts

@@ -0,0 +1,27 @@
+/**
+ * Query results can contain duplicate column labels, e.g.
+ * `SELECT a.name, b.name, c.name ...` (#12452). The grid, sorting, filtering
+ * and copy paths all look columns up by name, so duplicates make them address
+ * the first match only.
+ *
+ * Rename duplicates once at the result boundary, Navicat-style:
+ * `name, name, name` -> `name, name_1, name_2`. Existing names are never
+ * reused, so a result that already contains `name_1` stays unambiguous.
+ */
+export function dedupeResultColumnNames(columns: readonly string[]): string[] {
+  const used = new Set<string>();
+  return columns.map((column) => {
+    if (!used.has(column)) {
+      used.add(column);
+      return column;
+    }
+    let suffix = 1;
+    let candidate = `${column}_${suffix}`;
+    while (used.has(candidate)) {
+      suffix += 1;
+      candidate = `${column}_${suffix}`;
+    }
+    used.add(candidate);
+    return candidate;
+  });
+}