googleapis · chelsea-lin · Mar 26, 2026 · Mar 25, 2026
@@ -247,7 +247,7 @@ def _export_gbq(
        )
        sql = compiled.sql

-        if (existing_table is not None) and _if_schema_match(
+        if (existing_table is not None) and _is_schema_match(
            existing_table.schema, array_value.schema
        ):
            # b/409086472: Uses DML for table appends and replacements to avoid
@@ -690,16 +690,16 @@ def _result_schema(
    )


-def _if_schema_match(
-    table_schema: Tuple[bigquery.SchemaField, ...], schema: schemata.ArraySchema
+def _is_schema_match(
+    table_schema: Tuple[bigquery.SchemaField, ...],
+    schema: schemata.ArraySchema,
 ) -> bool:
    if len(table_schema) != len(schema.items):
        return False
-    for field in table_schema:
-        if field.name not in schema.names:
+    for field, schema_item in zip(table_schema, schema.items):
+        if field.name != schema_item.column:
            return False
-        if bigframes.dtypes.convert_schema_field(field)[1] != schema.get_type(
-            field.name
-        ):
+        _, field_dtype = bigframes.dtypes.convert_schema_field(field)
+        if field_dtype != schema_item.dtype:
            return False
    return True
@@ -631,6 +631,13 @@ def test_to_gbq_if_exists_is_replace(scalars_dfs, dataset_id):
    assert len(gcs_df) == len(scalars_pandas_df)
    pd.testing.assert_index_equal(gcs_df.columns, scalars_pandas_df.columns)

+    # When replacing a table with same schema but different column order
+    reordered_df = scalars_df[scalars_df.columns[::-1]]
+    reordered_df.to_gbq(destination_table, if_exists="replace")
+    gcs_df = pandas_gbq.read_gbq(destination_table, index_col="rowindex")
+    assert len(gcs_df) == len(scalars_pandas_df)
+    pd.testing.assert_index_equal(gcs_df.columns, reordered_df.columns)
+
    # When replacing a table with different schema
    partitial_scalars_df = scalars_df.drop(columns=["string_col"])
    partitial_scalars_df.to_gbq(destination_table, if_exists="replace")