1 files changed, 5 insertions, 5 deletions
diff --git a/sql/sql_union.cc b/sql/sql_union.cc
index 528292e5177..e10c0af2e16 100644
--- a/sql/sql_union.cc
+++ b/sql/sql_union.cc
@@ -1085,12 +1085,12 @@ cont:
 
     while ((type= tp++))
     {
-      if (type->cmp_type() == STRING_RESULT &&
-          type->collation.derivation == DERIVATION_NONE)
-      {
-        my_error(ER_CANT_AGGREGATE_NCOLLATIONS, MYF(0), "UNION");
+      /*
+        Test if the aggregated data type is OK for a UNION element.
+        E.g. in case of string data, DERIVATION_NONE is not allowed.
+      */
+      if (type->type_handler()->union_element_finalize(type))
         goto err;
-      }
     }
     
     /*