diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/utils/adt/selfuncs.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c index 55e42025c6b..d700b86b934 100644 --- a/src/backend/utils/adt/selfuncs.c +++ b/src/backend/utils/adt/selfuncs.c @@ -3068,8 +3068,13 @@ estimate_num_groups(PlannerInfo *root, List *groupExprs, double input_rows) double numdistinct; ListCell *l; - /* We should not be called unless query has GROUP BY (or DISTINCT) */ - Assert(groupExprs != NIL); + /* + * If no grouping columns, there's exactly one group. (This can't happen + * for normal cases with GROUP BY or DISTINCT, but it is possible for + * corner cases with set operations.) + */ + if (groupExprs == NIL) + return 1.0; /* * Count groups derived from boolean grouping expressions. For other |