diff options
Diffstat (limited to 'src/backend/parser/parse_collate.c')
| -rw-r--r-- | src/backend/parser/parse_collate.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/src/backend/parser/parse_collate.c b/src/backend/parser/parse_collate.c index 0b77e3ea2b7..8860679ccb9 100644 --- a/src/backend/parser/parse_collate.c +++ b/src/backend/parser/parse_collate.c @@ -533,6 +533,30 @@ assign_collations_walker(Node *node, assign_collations_context *context) collation = loccontext.collation; strength = loccontext.strength; location = loccontext.location; + + /* + * Throw error if the collation is indeterminate for a TargetEntry + * that is a sort/group target. We prefer to do this now, instead + * of leaving the comparison functions to fail at runtime, because + * we can give a syntax error pointer to help locate the problem. + * There are some cases where there might not be a failure, for + * example if the planner chooses to use hash aggregation instead + * of sorting for grouping; but it seems better to predictably + * throw an error. (Compare transformSetOperationTree, which will + * throw error for indeterminate collation of set-op columns, + * even though the planner might be able to implement the set-op + * without sorting.) + */ + if (strength == COLLATE_CONFLICT && + ((TargetEntry *) node)->ressortgroupref != 0) + ereport(ERROR, + (errcode(ERRCODE_COLLATION_MISMATCH), + errmsg("collation mismatch between implicit collations \"%s\" and \"%s\"", + get_collation_name(loccontext.collation), + get_collation_name(loccontext.collation2)), + errhint("You can choose the collation by applying the COLLATE clause to one or both expressions."), + parser_errposition(context->pstate, + loccontext.location2))); break; case T_RangeTblRef: case T_JoinExpr: |