diff --git a/vortex-sqllogictest/slt/string-hasjoin.slt b/vortex-sqllogictest/slt/string-hasjoin.slt
new file mode 100644
index 00000000000..ab7a8571b06
--- /dev/null
+++ b/vortex-sqllogictest/slt/string-hasjoin.slt
@@ -0,0 +1,21 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright the Vortex contributors
+
+# Check a string table hashjoin with itself works correctly.
+
+include ./setup.slt
+
+query I
+COPY (SELECT '' as id) TO '$__TEST_DIR__/hashjoin.vortex';
+----
+1
+
+query T
+SELECT first(t) AS sales
+FROM (
+    SELECT id, 0 as t FROM read_vortex('$__TEST_DIR__/hashjoin.vortex')
+    UNION ALL SELECT id, 0 as t FROM read_vortex('$__TEST_DIR__/hashjoin.vortex')
+)
+GROUP BY id;
+----
+0