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Diffstat (limited to 'lib/sqlalchemy/sql/selectable.py')
| -rw-r--r-- | lib/sqlalchemy/sql/selectable.py | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/lib/sqlalchemy/sql/selectable.py b/lib/sqlalchemy/sql/selectable.py index bf6f20436..59c292a07 100644 --- a/lib/sqlalchemy/sql/selectable.py +++ b/lib/sqlalchemy/sql/selectable.py @@ -4929,7 +4929,15 @@ class Exists(UnaryExpression): # use on an existing select() s = select([table.c.col1]).where(table.c.col2==5) - s = exists(s) + s_e = exists(s) + + # an exists is usually used in a where of another select + # to produce a WHERE EXISTS (SELECT ... ) + select([table.c.col1]).where(s_e) + + # but can also be used in a select to produce a + # SELECT EXISTS (SELECT ... ) query + select([s_e]) # construct a select() at once exists(['*'], **select_arguments).where(criterion) |