diff options
Diffstat (limited to 'sqlglot/optimizer/simplify.py')
-rw-r--r-- | sqlglot/optimizer/simplify.py | 26 |
1 files changed, 25 insertions, 1 deletions
diff --git a/sqlglot/optimizer/simplify.py b/sqlglot/optimizer/simplify.py index 1a2d82c..e247f58 100644 --- a/sqlglot/optimizer/simplify.py +++ b/sqlglot/optimizer/simplify.py @@ -8,6 +8,9 @@ from sqlglot import exp from sqlglot.generator import cached_generator from sqlglot.helper import first, while_changing +# Final means that an expression should not be simplified +FINAL = "final" + def simplify(expression): """ @@ -27,8 +30,29 @@ def simplify(expression): generate = cached_generator() + # group by expressions cannot be simplified, for example + # select x + 1 + 1 FROM y GROUP BY x + 1 + 1 + # the projection must exactly match the group by key + for group in expression.find_all(exp.Group): + select = group.parent + groups = set(group.expressions) + group.meta[FINAL] = True + + for e in select.selects: + for node, *_ in e.walk(): + if node in groups: + e.meta[FINAL] = True + break + + having = select.args.get("having") + if having: + for node, *_ in having.walk(): + if node in groups: + having.meta[FINAL] = True + break + def _simplify(expression, root=True): - if expression.meta.get("final"): + if expression.meta.get(FINAL): return expression node = expression node = rewrite_between(node) |