diff --git a/apps/desktop/src/lib/__tests__/sql/upperFoldingIdentifierQuoting.spec.ts b/apps/desktop/src/lib/__tests__/sql/upperFoldingIdentifierQuoting.spec.ts
new file mode 100644
index 0000000000..930750ecbc
--- /dev/null
+++ b/apps/desktop/src/lib/__tests__/sql/upperFoldingIdentifierQuoting.spec.ts
@@ -0,0 +1,47 @@
+import { describe, expect, it } from "vitest";
+import { buildSqlCompletionItems } from "@/lib/sql/sqlCompletion";
+
+describe("upper-folding completion with identifier quoting disabled (#9775)", () => {
+  const sql = "SELECT t.c FROM abc t";
+  const cursor = "SELECT t.c".length;
+  const columnApplyOf = (databaseType: "dameng" | "db2", extra: { quoteIdentifiers?: boolean }) =>
+    buildSqlCompletionItems(sql, cursor, {
+      databaseType,
+      tables: [{ name: "abc", type: "table" as const }],
+      columnsByTable: new Map([["abc", [{ name: "col1", table: "abc" }]]]),
+      ...extra,
+    }).find((item) => item.label === "col1")?.apply;
+
+  it.each(["dameng", "db2"] as const)("keeps lowercase columns bare on %s when quoting is disabled", (databaseType) => {
+    expect(columnApplyOf(databaseType, { quoteIdentifiers: false })).toBe("col1");
+  });
+
+  it.each(["dameng", "db2"] as const)("still quotes lowercase columns on %s by default and when quoting is enabled", (databaseType) => {
+    expect(columnApplyOf(databaseType, {})).toBe('"col1"');
+    expect(columnApplyOf(databaseType, { quoteIdentifiers: true })).toBe('"col1"');
+  });
+
+  it.each(["dameng", "db2"] as const)("keeps mixed-case table names bare on %s when quoting is disabled", (databaseType) => {
+    const tableSql = "SELECT * FROM Ab";
+    const items = buildSqlCompletionItems(tableSql, tableSql.length, {
+      databaseType,
+      tables: [{ name: "Abc", type: "table" as const }],
+      columnsByTable: new Map(),
+      quoteIdentifiers: false,
+    });
+    expect(items.find((item) => item.label === "Abc")?.apply).toBe("Abc");
+  });
+
+  it.each(["dameng", "db2"] as const)("keeps all-uppercase columns bare on %s regardless of the setting", (databaseType) => {
+    const upperSql = "SELECT t.c FROM abc t";
+    const applyOf = (extra: { quoteIdentifiers?: boolean }) =>
+      buildSqlCompletionItems(upperSql, "SELECT t.c".length, {
+        databaseType,
+        tables: [{ name: "abc", type: "table" as const }],
+        columnsByTable: new Map([["abc", [{ name: "COL1", table: "abc" }]]]),
+        ...extra,
+      }).find((item) => item.label === "COL1")?.apply;
+    expect(applyOf({ quoteIdentifiers: false })).toBe("COL1");
+    expect(applyOf({ quoteIdentifiers: true })).toBe("COL1");
+  });
+});
diff --git a/apps/desktop/src/lib/sql/sqlCompletion.ts b/apps/desktop/src/lib/sql/sqlCompletion.ts
index 743eba22a5..3ded3d5232 100644
--- a/apps/desktop/src/lib/sql/sqlCompletion.ts
+++ b/apps/desktop/src/lib/sql/sqlCompletion.ts
@@ -1659,8 +1659,9 @@ class SqlCompletionProvider {
   ) {
     this.t = input.translations;
     const dialect = sqlCompletionApplyDialect(input.databaseType, input.dialect);
-    // "Quote identifiers in generated SQL" off: Oracle completion inserts bare names instead of quoting lowercase ones.
-    this.dialect = dialect === "oracle" && input.quoteIdentifiers === false ? undefined : dialect;
+    // "Quote identifiers in generated SQL" off: Oracle-like and upper-folding (Dameng, DB2)
+    // completions insert bare names instead of quoting mixed-case ones.
+    this.dialect = input.quoteIdentifiers === false && (dialect === "oracle" || dialect === "upper") ? undefined : dialect;
     this.databaseType = input.databaseType;
   }