dont create with expression without ctes

Author: TrevorBergeron

bigframes/core/compile/sqlglot/compiler.py

@@ -366,16 +366,3 @@ def _replace_unsupported_ops(node: nodes.BigFrameNode):
     node = nodes.bottom_up(node, rewrite.rewrite_slice)
     node = nodes.bottom_up(node, rewrite.rewrite_range_rolling)
     return node
-
-
-def _get_ctes(root: nodes.ResultNode) -> typing.Sequence[nodes.CteNode]:
-    """
-    Get ctes from plan in topological order.
-    """
-
-    def merge_list(node, cte_list):
-        if isinstance(node, nodes.CteNode):
-            return (*cte_list, node)
-        return cte_list
-
-    return root.reduce_up(merge_list)

bigframes/core/compile/sqlglot/sqlglot_ir.py

@@ -503,13 +503,13 @@ def _explode_multiple_columns(
     def _as_from_item(self) -> typing.Union[sge.Subquery, sge.Table]:
         if isinstance(self.expr, sge.Select):
             return self.expr.subquery()
-        else:  # table
+        else:  # table or cte
             return self.expr
 
     def _as_select(self) -> sge.Select:
         if isinstance(self.expr, sge.Select):
             return self.expr
-        else:  # table
+        else:  # table or cte
             return (
                 sge.Select()
                 .select(sge.Column(this=sge.Star(), table=self.expr))

bigframes/core/rewrite/as_sql.py

@@ -228,6 +228,9 @@ def _extract_ctes(root: nodes.BigFrameNode) -> nodes.BigFrameNode:
     )
     cte_names = tuple(f"bfcte_{i}" for i in range(len(topological_ctes)))
 
+    if len(topological_ctes) == 0:
+        return root
+
     mapping = {
         cte_node: sql_nodes.SqlCteRefNode(cte_name, tuple(cte_node.fields))
         for cte_node, cte_name in zip(topological_ctes, cte_names)

bigframes/core/rewrite/ctes.py

@@ -25,13 +25,9 @@ def extract_ctes(root: nodes.BigFrameNode) -> nodes.BigFrameNode:
         for child in parent.child_nodes:
             node_parents[child] += 1
 
-    counter = 0
-
     # we just mark in place, rather than pull out of the tree.
     def insert_cte_markers(node: nodes.BigFrameNode) -> nodes.BigFrameNode:
-        nonlocal counter
         if node_parents[node] > 1:
-            counter += 1
             return nodes.CteNode(node)
         return node
 

tests/unit/core/compile/sqlglot/aggregations/snapshots/test_binary_compiler/test_corr/out.sql

@@ -1,10 +1,4 @@
-SELECT
-  (
-    SELECT
-      `bfcol_2` AS `corr_col`
-    FROM `bigframes-dev`.`sqlglot_test`.`scalar_types` AS `bft_0`
-  ).*
-FROM (
+(
   SELECT
     `bfcol_2` AS `corr_col`
   FROM `bigframes-dev`.`sqlglot_test`.`scalar_types` AS `bft_0`

tests/unit/core/compile/sqlglot/aggregations/snapshots/test_binary_compiler/test_cov/out.sql

@@ -1,10 +1,4 @@
-SELECT
-  (
-    SELECT
-      `bfcol_2` AS `cov_col`
-    FROM `bigframes-dev`.`sqlglot_test`.`scalar_types` AS `bft_0`
-  ).*
-FROM (
+(
   SELECT
     `bfcol_2` AS `cov_col`
   FROM `bigframes-dev`.`sqlglot_test`.`scalar_types` AS `bft_0`

tests/unit/core/compile/sqlglot/aggregations/snapshots/test_nullary_compiler/test_size/out.sql

@@ -1,10 +1,4 @@
-SELECT
-  (
-    SELECT
-      `bfcol_32` AS `size`
-    FROM `bigframes-dev`.`sqlglot_test`.`scalar_types` AS `bft_0`
-  ).*
-FROM (
+(
   SELECT
     `bfcol_32` AS `size`
   FROM `bigframes-dev`.`sqlglot_test`.`scalar_types` AS `bft_0`

tests/unit/core/compile/sqlglot/aggregations/snapshots/test_ordered_unary_compiler/test_array_agg/out.sql

@@ -1,10 +1,4 @@
-SELECT
-  (
-    SELECT
-      `bfcol_1` AS `int64_col`
-    FROM `bigframes-dev`.`sqlglot_test`.`scalar_types` AS `bft_0`
-  ).*
-FROM (
+(
   SELECT
     `bfcol_1` AS `int64_col`
   FROM `bigframes-dev`.`sqlglot_test`.`scalar_types` AS `bft_0`

tests/unit/core/compile/sqlglot/aggregations/snapshots/test_ordered_unary_compiler/test_string_agg/out.sql

@@ -1,10 +1,4 @@
-SELECT
-  (
-    SELECT
-      `bfcol_1` AS `string_col`
-    FROM `bigframes-dev`.`sqlglot_test`.`scalar_types` AS `bft_0`
-  ).*
-FROM (
+(
   SELECT
     `bfcol_1` AS `string_col`
   FROM `bigframes-dev`.`sqlglot_test`.`scalar_types` AS `bft_0`

tests/unit/core/compile/sqlglot/aggregations/snapshots/test_unary_compiler/test_all/out.sql

@@ -1,11 +1,4 @@
-SELECT
-  (
-    SELECT
-      `bfcol_2` AS `bool_col`,
-      `bfcol_3` AS `int64_col`
-    FROM `bigframes-dev`.`sqlglot_test`.`scalar_types` AS `bft_0`
-  ).*
-FROM (
+(
   SELECT
     `bfcol_2` AS `bool_col`,
     `bfcol_3` AS `int64_col`