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fix!: unnest deep stuff #6366

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Merged
merged 1 commit into from
Nov 20, 2025
Merged

fix!: unnest deep stuff #6366

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5 changes: 5 additions & 0 deletions sqlglot/optimizer/qualify_tables.py
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Original file line number Diff line number Diff line change
Expand Up @@ -75,6 +75,11 @@ def _qualify(table: exp.Table) -> None:
_qualify(node)

for scope in traverse_scope(expression):
for query in scope.subqueries:
subquery = query.parent
if isinstance(subquery, exp.Subquery):
subquery.unwrap().replace(subquery)
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@georgesittas georgesittas Nov 20, 2025

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Do we need to fix the scope's state, e.g. reset cache?

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@tobymao tobymao Nov 20, 2025

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i don’t think so, not sure scope changes at all


for derived_table in scope.derived_tables:
unnested = derived_table.unnest()
if isinstance(unnested, exp.Table):
Expand Down
9 changes: 3 additions & 6 deletions sqlglot/optimizer/scope.py
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Expand Up @@ -156,7 +156,7 @@ def _collect(self):
self._ctes.append(node)
elif _is_derived_table(node) and _is_from_or_join(node):
self._derived_tables.append(node)
elif isinstance(node, exp.UNWRAPPED_QUERIES):
elif isinstance(node, exp.UNWRAPPED_QUERIES) and not _is_from_or_join(node):
self._subqueries.append(node)
elif isinstance(node, exp.TableColumn):
self._table_columns.append(node)
Expand Down Expand Up @@ -821,7 +821,7 @@ def _traverse_udtfs(scope):

sources = {}
for expression in expressions:
if _is_derived_table(expression):
if isinstance(expression, exp.Subquery):
top = None
for child_scope in _traverse_scope(
scope.branch(
Expand Down Expand Up @@ -870,10 +870,7 @@ def walk_in_scope(expression, bfs=True, prune=None):

if (
isinstance(node, exp.CTE)
or (
isinstance(node.parent, (exp.From, exp.Join, exp.Subquery))
and _is_derived_table(node)
)
or (isinstance(node.parent, (exp.From, exp.Join)) and _is_derived_table(node))
or (isinstance(node.parent, exp.UDTF) and isinstance(node, exp.Query))
or isinstance(node, exp.UNWRAPPED_QUERIES)
):
Expand Down
6 changes: 5 additions & 1 deletion tests/fixtures/optimizer/qualify_columns.sql
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Expand Up @@ -337,7 +337,7 @@ SELECT _q_0.a AS a FROM (SELECT x.a AS a FROM x AS x UNION SELECT x.a AS a FROM

# title: nested subqueries in union
((select a from x where a < 1)) UNION ((select a from x where a > 2));
((SELECT x.a AS a FROM x AS x WHERE x.a < 1)) UNION ((SELECT x.a AS a FROM x AS x WHERE x.a > 2));
(SELECT x.a AS a FROM x AS x WHERE x.a < 1) UNION (SELECT x.a AS a FROM x AS x WHERE x.a > 2);


# dialect: bigquery
Expand Down Expand Up @@ -443,6 +443,10 @@ SELECT _q_1.a AS a FROM (SELECT x.a AS a FROM x AS x) AS _q_1 WHERE _q_1.a IN (S
SELECT * FROM table_a as A WHERE A.col1 IN (SELECT MAX(B.col2) FROM table_b as B UNION ALL SELECT MAX(C.col2) FROM table_b as C);
SELECT * FROM table_a AS `A` WHERE `A`.col1 IN (SELECT MAX(`B`.col2) AS _col_0 FROM table_b AS `B` UNION ALL SELECT MAX(`C`.col2) AS _col_0 FROM table_b AS `C`);

# Title: Unnest deep subquery
select * from x where b in ((((select b from y))));
SELECT x.a AS a, x.b AS b FROM x AS x WHERE x.b IN (SELECT y.b AS b FROM y AS y);

--------------------------------------
-- Correlated subqueries
--------------------------------------
Expand Down