add test for unsupported update query

the test may be more complicated than required, but I wanted to base the test case on the bug report here - dathere/qsv#2450

py-polars/tests/unit/sql/test_set_ops.py

@@ -89,6 +89,54 @@ def test_except_intersect_all_unsupported(op: str, op_subtype: str) -> None:
         pl.sql(f"SELECT * FROM df1 {op} {op_subtype} SELECT * FROM df2")
 
 
+def test_update_statement_error() -> None:
+    df_large = pl.DataFrame(
+        {  # noqa: F841
+            "FQDN": ["c.ORG.na", "a.COM.na"],
+            "NS1": ["ns1.c.org.na", "ns1.d.net.na"],
+            "NS2": ["ns2.c.org.na", "ns2.d.net.na"],
+            "NS3": ["ns3.c.org.na", "ns3.d.net.na"],
+        }
+    )
+    df_small = pl.DataFrame(
+        {  # noqa: F841
+            "FQDN": ["c.org.na"],
+            "NS1": ["ns1.c.org.na|127.0.0.1"],
+            "NS2": ["ns2.c.org.na|127.0.0.1"],
+            "NS3": ["ns3.c.org.na|127.0.0.1"],
+        }
+    )
+
+    # Create a context and register the tables
+    ctx = pl.SQLContext()
+    ctx.register("large", df_large)
+    ctx.register("small", df_small)
+
+    with pytest.raises(
+        SQLInterfaceError,
+        match="'UPDATE large SET FQDN = u.FQDN, NS1 = u.NS1, NS2 = u.NS2, NS3 = u.NS3 FROM u WHERE large.FQDN = u.FQDN' operation is currently unsupported",
+    ):
+        ctx.execute("""
+            WITH u AS (
+                SELECT 
+                    small.FQDN,
+                    small.NS1,
+                    small.NS2,
+                    small.NS3
+                FROM small
+                INNER JOIN large ON small.FQDN = large.FQDN
+            )
+            UPDATE large 
+            SET 
+                FQDN = u.FQDN,
+                NS1 = u.NS1,
+                NS2 = u.NS2,
+                NS3 = u.NS3
+            FROM u
+            WHERE large.FQDN = u.FQDN
+        """)
+
+
 @pytest.mark.parametrize("op", ["EXCEPT", "INTERSECT", "UNION"])
 def test_except_intersect_errors(op: str) -> None:
     df1 = pl.DataFrame({"x": [1, 9, 1, 1], "y": [2, 3, 4, 4], "z": [5, 5, 5, 5]})  # noqa: F841