desktop/src/components/db-viewer/DbViewerScreen.tsx

@@ -22,6 +22,8 @@ import { VirtualDataGrid } from "../grid/VirtualDataGrid";
 import { ResultSetPanels } from "./ResultSetPanels";
 import { RowDetailDrawer } from "../grid/RowDetailDrawer";
 import { TableControls } from "./TableControls";
+import { StreamExportDialog } from "./StreamExportDialog";
+import { qualifiedTableSql } from "../../lib/exportData";
 import { EditConnectionModal } from "./EditConnectionModal";
 import { PasswordPromptDialog } from "./PasswordPromptDialog";
 import { useDbConnection } from "../../hooks/useDbConnection";
@@ -178,6 +180,7 @@ export function DbViewerScreen({
     const [rowDetailIdx, setRowDetailIdx] = useState<number | null>(null);
     const [editModalOpen, setEditModalOpen] = useState(false);
     const [destructiveQuery, setDestructiveQuery] = useState<string | null>(null);
+    const [streamExport, setStreamExport] = useState<{ sql: string } | null>(null);
     const connections = useConnectionStore((s) => s.connections);
     const currentConnection =
         connections.find((c) => c.id === connectionId) ?? null;
@@ -1269,6 +1272,18 @@ const onQueriesPanelResizeStart = useCallback(
                                                                 }
                                                                 variant="query"
                                                                 isMatview={readOnlyTable}
+                                                                onExportToFile={() =>
+                                                                    setStreamExport({
+                                                                        sql:
+                                                                            activeTab?.tabType === "query"
+                                                                                ? activeTab.query ?? ""
+                                                                                : qualifiedTableSql(
+                                                                                      currentConnection?.db_type ?? "postgresql",
+                                                                                      activeSchema,
+                                                                                      activeTable,
+                                                                                  ),
+                                                                    })
+                                                                }
                                                             />
                                                         )}
                                                         <div className="flex-1 flex flex-col min-h-0 overflow-hidden">
@@ -1380,6 +1395,18 @@ const onQueriesPanelResizeStart = useCallback(
                                                     setSelectedRows(new Set())
                                                 }
                                                 isMatview={readOnlyTable}
+                                                onExportToFile={() =>
+                                                    setStreamExport({
+                                                        sql:
+                                                            activeTab?.tabType === "query"
+                                                                ? activeTab.query ?? ""
+                                                                : qualifiedTableSql(
+                                                                      currentConnection?.db_type ?? "postgresql",
+                                                                      activeSchema,
+                                                                      activeTable,
+                                                                  ),
+                                                    })
+                                                }
                                             />
                                         )}
                                         <div className="flex-1 flex flex-col min-h-0 overflow-hidden">
@@ -1572,6 +1599,13 @@ const onQueriesPanelResizeStart = useCallback(
                 {capabilities.objects && (
                     <ObjectSearchPalette connectionId={connectionId} />
                 )}
+                {streamExport && (
+                    <StreamExportDialog
+                        connectionId={connectionId}
+                        sql={streamExport.sql}
+                        onClose={() => setStreamExport(null)}
+                    />
+                )}
             </div>
         </TooltipProvider>
     );

desktop/src/components/db-viewer/StreamExportDialog.test.tsx

@@ -0,0 +1,44 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { render, screen, fireEvent, waitFor } from "@testing-library/react";
+
+vi.mock("@tauri-apps/plugin-dialog", () => ({
+  save: vi.fn().mockResolvedValue("/tmp/export.csv"),
+}));
+vi.mock("../../lib/commands", () => ({
+  exportQueryToFile: vi.fn().mockResolvedValue({ rows_written: 3 }),
+  cancelQuery: vi.fn().mockResolvedValue(undefined),
+}));
+vi.mock("@tauri-apps/api/event", () => ({
+  listen: vi.fn().mockResolvedValue(() => {}),
+}));
+
+import { StreamExportDialog } from "./StreamExportDialog";
+import { save } from "@tauri-apps/plugin-dialog";
+import { exportQueryToFile, cancelQuery } from "../../lib/commands";
+
+describe("StreamExportDialog", () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it("picks a path, invokes the export, and reports the row count", async () => {
+    render(<StreamExportDialog connectionId="c1" sql="SELECT 1" onClose={vi.fn()} />);
+    fireEvent.click(screen.getByRole("button", { name: /choose file/i }));
+    expect(save).toHaveBeenCalled();
+    fireEvent.click(screen.getByRole("button", { name: /export/i }));
+    await waitFor(() => expect(exportQueryToFile).toHaveBeenCalledWith("c1", "SELECT 1", "csv", "/tmp/export.csv"));
+    await waitFor(() => expect(screen.getByText(/3 rows written/i)).toBeTruthy());
+  });
+
+  it("cancels via the existing query-cancel wrapper", async () => {
+    render(<StreamExportDialog connectionId="c1" sql="SELECT 1" onClose={vi.fn()} />);
+    fireEvent.click(screen.getByRole("button", { name: /export/i }));
+    fireEvent.click(screen.getByRole("button", { name: /cancel/i }));
+    await waitFor(() => expect(cancelQuery).toHaveBeenCalledWith("c1"));
+  });
+
+  it("surfaces export errors", async () => {
+    (exportQueryToFile as ReturnType<typeof vi.fn>).mockRejectedValueOnce(new Error("boom"));
+    render(<StreamExportDialog connectionId="c1" sql="SELECT 1" onClose={vi.fn()} />);
+    fireEvent.click(screen.getByRole("button", { name: /export/i }));
+    await waitFor(() => expect(screen.getByText(/boom/i)).toBeTruthy());
+  });
+});

desktop/src/components/db-viewer/StreamExportDialog.tsx

@@ -0,0 +1,160 @@
+import { useState, useEffect, useRef } from "react";
+import { AnimatedModal } from "../ui/AnimatedModal";
+import { Button } from "../ui/Button";
+import { Select } from "../ui/Select";
+import { save } from "@tauri-apps/plugin-dialog";
+import { listen } from "@tauri-apps/api/event";
+import { exportQueryToFile, cancelQuery } from "../../lib/commands";
+
+interface StreamExportDialogProps {
+  connectionId: string;
+  sql: string;
+  onClose: () => void;
+}
+
+const FORMAT_OPTIONS = [
+  { value: "csv", label: "CSV" },
+  { value: "jsonl", label: "JSON Lines" },
+  { value: "json", label: "JSON" },
+];
+
+const EXTENSIONS: Record<string, string> = {
+  csv: "csv",
+  jsonl: "jsonl",
+  json: "json",
+};
+
+export function StreamExportDialog({ connectionId, sql, onClose }: StreamExportDialogProps) {
+  const [format, setFormat] = useState("csv");
+  const [path, setPath] = useState("");
+  const [running, setRunning] = useState(false);
+  const [progress, setProgress] = useState(0);
+  const [done, setDone] = useState(false);
+  const [rowsWritten, setRowsWritten] = useState<number | null>(null);
+  const [error, setError] = useState<string | null>(null);
+  const jobIdRef = useRef<string | null>(null);
+
+  // Filter export-progress events to this job so concurrent exports don't
+  // clobber each other's progress bar.
+  useEffect(() => {
+    const unlisten = listen<{ job_id: string; percent: number }>("export-progress", (e) => {
+      if (e.payload.job_id === jobIdRef.current) {
+        setProgress(e.payload.percent);
+      }
+    });
+    return () => {
+      unlisten.then((fn) => fn());
+    };
+  }, []);
+
+  const handleChooseFile = async () => {
+    const ext = EXTENSIONS[format] ?? "csv";
+    const picked = await save({
+      defaultPath: `export.${ext}`,
+      filters: [{ name: format.toUpperCase(), extensions: [ext] }],
+    });
+    if (picked) setPath(picked);
+  };
+
+  const handleExport = async () => {
+    setRunning(true);
+    setError(null);
+    setDone(false);
+    setProgress(0);
+    try {
+      let target = path;
+      if (!target) {
+        const ext = EXTENSIONS[format] ?? "csv";
+        target = (await save({
+          defaultPath: `export.${ext}`,
+          filters: [{ name: format.toUpperCase(), extensions: [ext] }],
+        })) ?? "";
+        if (!target) {
+          setRunning(false);
+          return;
+        }
+        setPath(target);
+      }
+      jobIdRef.current = `export-${Date.now()}`;
+      const res = await exportQueryToFile(connectionId, sql, format, target);
+      setDone(true);
+      setProgress(100);
+      setRowsWritten(res.rows_written);
+    } catch (e) {
+      setError(e instanceof Error ? e.message : String(e));
+    } finally {
+      setRunning(false);
+    }
+  };
+
+  const handleCancel = async () => {
+    try {
+      await cancelQuery(connectionId);
+    } catch {
+      // ignore — the export may already have finished
+    }
+    setRunning(false);
+  };
+
+  return (
+    <AnimatedModal open onClose={onClose}>
+      <div className="w-[420px] flex flex-col gap-4">
+        <h2 className="text-base font-semibold text-text">Export all rows to file</h2>
+
+        <div className="flex items-center gap-3">
+          <Select
+            label="Format"
+            value={format}
+            onChange={setFormat}
+            options={FORMAT_OPTIONS}
+            disabled={running}
+          />
+          <Button variant="secondary" onClick={handleChooseFile} disabled={running}>
+            Choose file…
+          </Button>
+        </div>
+
+        {path && (
+          <p className="text-xs text-text-muted break-all" data-testid="export-path">
+            {path}
+          </p>
+        )}
+
+        {running && (
+          <div className="flex flex-col gap-1">
+            <div className="h-1.5 w-full rounded-full bg-surface-raised overflow-hidden">
+              <div
+                className="h-full bg-accent transition-all"
+                style={{ width: `${Math.max(progress, 2)}%` }}
+              />
+            </div>
+            <span className="text-xs text-text-muted">{Math.round(progress)}%</span>
+          </div>
+        )}
+
+        {done && rowsWritten !== null && (
+          <p className="text-xs text-emerald-400" data-testid="export-done">
+            {rowsWritten} rows written
+          </p>
+        )}
+
+        {error && (
+          <p className="text-xs text-red-400" data-testid="export-error">
+            {error}
+          </p>
+        )}
+
+        <div className="flex justify-end gap-2">
+          {running && (
+            <Button variant="secondary" onClick={handleCancel}>
+              Cancel
+            </Button>
+          )}
+          <Button onClick={handleExport} disabled={running}>
+            Export
+          </Button>
+        </div>
+      </div>
+    </AnimatedModal>
+  );
+}

desktop/src/components/db-viewer/TableControls.tsx

@@ -467,6 +467,8 @@ interface TableControlsProps {
   isMatview?: boolean;
   /** "table" = full table toolbar; "query" = export/refresh/columns + timing */
   variant?: "table" | "query";
+  /** Open the full-result streamed export dialog. */
+  onExportToFile?: () => void;
 }
 
 export function TableControls({
@@ -488,6 +490,7 @@ export function TableControls({
   defaultRefreshRate = 0,
   isMatview = false,
   variant = "table",
+  onExportToFile,
 }: TableControlsProps) {
   const isQuery = variant === "query";
   const notify = useNotificationStore((s) => s.notify);
@@ -636,6 +639,21 @@ export function TableControls({
             {fmt.label}
           </button>
         ))}
+        {onExportToFile && (
+          <>
+            <div className="my-1 h-px bg-border" />
+            <button
+              type="button"
+              onClick={() => {
+                setExportOpen(false);
+                onExportToFile();
+              }}
+              className="w-full px-3 py-1.5 text-xs text-left text-text hover:bg-surface-raised transition-colors cursor-pointer"
+            >
+              Export all rows to file…
+            </button>
+          </>
+        )}
       </DropdownMenu>
     </div>
   );

desktop/src/lib/commands.ts

@@ -295,6 +295,15 @@ export async function executeQueryMulti(
   return invoke<MultiQueryResult>("execute_query_multi", { connectionId, query, page, pageSize });
 }
 
+export async function exportQueryToFile(
+  connectionId: string,
+  sql: string,
+  format: string,
+  path: string,
+): Promise<{ rows_written: number; path: string }> {
+  return invoke("export_query_to_file", { connectionId, sql, format, path });
+}
+
 export async function getQueryHistory(
   connectionId: string | null,
   limit: number,

desktop/src/lib/exportData.test.ts

@@ -1,5 +1,5 @@
 import { describe, it, expect, vi } from "vitest";
-import { exportData } from "./exportData";
+import { exportData, csvCell, qualifiedTableSql } from "./exportData";
 import type { ColumnInfo } from "./types";
 
 const columns: ColumnInfo[] = [
@@ -49,3 +49,25 @@ describe("exportData", () => {
     }
   });
 });
+
+describe("csvCell (client CSV parity with streamed export)", () => {
+  it("quotes and guards like the Rust writer", () => {
+    expect(csvCell("plain")).toBe("plain");
+    expect(csvCell("a,b")).toBe('"a,b"');
+    expect(csvCell('a"b')).toBe('"a""b"');
+    expect(csvCell("=SUM(A1)")).toBe("'=SUM(A1)");
+    expect(csvCell("+x")).toBe("'+x");
+    expect(csvCell("-1")).toBe("'-1");
+    expect(csvCell("@cmd")).toBe("'@cmd");
+    expect(csvCell(null)).toBe("");
+  });
+});
+
+describe("qualifiedTableSql", () => {
+  it("double-quotes for PG/SQLite and backticks for MySQL/MariaDB", () => {
+    expect(qualifiedTableSql("postgresql", "public", "users")).toBe('SELECT * FROM "public"."users"');
+    expect(qualifiedTableSql("sqlite", "main", "users")).toBe('SELECT * FROM "main"."users"');
+    expect(qualifiedTableSql("mysql", "app", "users")).toBe("SELECT * FROM `app`.`users`");
+    expect(qualifiedTableSql("mariadb", "app", "users")).toBe("SELECT * FROM `app`.`users`");
+  });
+});

desktop/src/lib/exportData.ts

@@ -1,6 +1,27 @@
 import { buildXlsx } from "./xlsx";
 import type { ColumnInfo } from "./types";
 
+/** Quote one CSV cell with formula-injection protection — mirrors the Rust
+ *  `csv_cell` from the streaming export (Task 10) byte-for-byte. */
+export function csvCell(value: unknown): string {
+  const s = value === null || value === undefined ? "" : String(value);
+  const guarded = /^[=+\-@\t\r]/.test(s) ? `'${s}` : s;
+  if (/[,"\n\r]/.test(guarded)) {
+    return `"${guarded.replace(/"/g, '""')}"`;
+  }
+  return guarded;
+}
+
+/** SQL selecting every row of a table, dialect-quoted. */
+export function qualifiedTableSql(dbType: string, schema: string, table: string): string {
+  if (dbType === "mysql" || dbType === "mariadb") {
+    const q = (s: string) => s.replace(/`/g, "``");
+    return `SELECT * FROM \`${q(schema)}\`.\`${q(table)}\``;
+  }
+  const q = (s: string) => s.replace(/"/g, '""');
+  return `SELECT * FROM "${q(schema)}"."${q(table)}"`;
+}
+
 export function exportData(
   rows: unknown[][],
   columns: ColumnInfo[],
@@ -34,14 +55,9 @@ export function exportData(
       break;
     }
     case "csv": {
-      const csvRows = [headers.map((h) => `"${h.replace(/"/g, '""')}"`).join(",")];
+      const csvRows = [headers.map((h) => csvCell(h)).join(",")];
       for (const row of rows) {
-        csvRows.push(
-          row.map((cell) => {
-            const s = cell === null || cell === undefined ? "" : String(cell);
-            return `"${s.replace(/"/g, '""')}"`;
-          }).join(","),
-        );
+        csvRows.push(row.map((cell) => csvCell(cell)).join(","));
       }
       content = csvRows.join("\n");
       mime = "text/csv";