correct indentifier for concat compiler

Author: chelsea-lin

bigframes/core/compile/sqlglot/sqlglot_ir.py

@@ -182,7 +182,7 @@ def from_union(
 
             selections = [
                 sge.Alias(
-                    this=expr.alias_or_name,
+                    this=sge.to_identifier(expr.alias_or_name, quoted=cls.quoted),
                     alias=sge.to_identifier(output_id, quoted=cls.quoted),
                 )
                 for expr, output_id in zip(select_expr.expressions, output_ids)

tests/unit/core/compile/sqlglot/snapshots/test_compile_concat/test_compile_concat/out.sql

@@ -49,21 +49,21 @@ WITH `bfcte_1` AS (
     *
   FROM (
     SELECT
-      bfcol_17 AS `bfcol_46`,
-      bfcol_18 AS `bfcol_47`,
-      bfcol_19 AS `bfcol_48`,
-      bfcol_20 AS `bfcol_49`,
-      bfcol_21 AS `bfcol_50`,
-      bfcol_22 AS `bfcol_51`
+      `bfcol_17` AS `bfcol_46`,
+      `bfcol_18` AS `bfcol_47`,
+      `bfcol_19` AS `bfcol_48`,
+      `bfcol_20` AS `bfcol_49`,
+      `bfcol_21` AS `bfcol_50`,
+      `bfcol_22` AS `bfcol_51`
     FROM `bfcte_6`
     UNION ALL
     SELECT
-      bfcol_40 AS `bfcol_46`,
-      bfcol_41 AS `bfcol_47`,
-      bfcol_42 AS `bfcol_48`,
-      bfcol_43 AS `bfcol_49`,
-      bfcol_44 AS `bfcol_50`,
-      bfcol_45 AS `bfcol_51`
+      `bfcol_40` AS `bfcol_46`,
+      `bfcol_41` AS `bfcol_47`,
+      `bfcol_42` AS `bfcol_48`,
+      `bfcol_43` AS `bfcol_49`,
+      `bfcol_44` AS `bfcol_50`,
+      `bfcol_45` AS `bfcol_51`
     FROM `bfcte_7`
   )
 )

tests/unit/core/compile/sqlglot/test_compile_concat.py

@@ -24,7 +24,7 @@
 def test_compile_concat(
     scalars_types_pandas_df: pd.DataFrame, compiler_session: bigframes.Session, snapshot
 ):
-    # TODO: concat dataframes from a gbq table but trigger a windows compiler.
+    # TODO(b/425739511): concat dataframes from a gbq table but trigger a windows compiler.
     df1 = bpd.DataFrame(scalars_types_pandas_df, session=compiler_session)
     df1 = df1[["rowindex", "int64_col", "string_col"]]
     concat_df = bpd.concat([df1, df1])