diff options
Diffstat (limited to 'sql/sql_select.cc')
| -rw-r--r-- | sql/sql_select.cc | 43 |
1 files changed, 40 insertions, 3 deletions
diff --git a/sql/sql_select.cc b/sql/sql_select.cc index 7bd09cb831d..2ade04e8592 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -517,12 +517,49 @@ JOIN::prepare(Item ***rref_pointer_array, tables_list, &select_lex->leaf_tables, FALSE, SELECT_ACL, SELECT_ACL)) DBUG_RETURN(-1); + /* + TRUE if the SELECT list mixes elements with and without grouping, + and there is no GROUP BY clause. Mixing non-aggregated fields with + aggregate functions in the SELECT list is a MySQL exptenstion that + is allowed only if the ONLY_FULL_GROUP_BY sql mode is not set. + */ + bool mixed_implicit_grouping= false; + if ((~thd->variables.sql_mode & MODE_ONLY_FULL_GROUP_BY) && + select_lex->with_sum_func && !group_list) + { + List_iterator_fast <Item> select_it(fields_list); + Item *select_el; /* Element of the SELECT clause, can be an expression. */ + bool found_field_elem= false; + bool found_sum_func_elem= false; + + while ((select_el= select_it++)) + { + if (select_el->with_sum_func) + found_sum_func_elem= true; + if (select_el->with_field) + found_field_elem= true; + if (found_sum_func_elem && found_field_elem) + { + mixed_implicit_grouping= true; + break; + } + } + } - TABLE_LIST *table_ptr; - for (table_ptr= select_lex->leaf_tables; + for (TABLE_LIST *table_ptr= select_lex->leaf_tables; table_ptr; table_ptr= table_ptr->next_leaf) - tables++; + { + tables++; /* Count the number of tables in the join. */ + /* + If the query uses implicit grouping where the select list contains both + aggregate functions and non-aggregate fields, any non-aggregated field + may produce a NULL value. Set all fields of each table as nullable before + semantic analysis to take into account this change of nullability. + */ + if (mixed_implicit_grouping) + table_ptr->table->maybe_null= 1; + } if (setup_wild(thd, tables_list, fields_list, &all_fields, wild_num) || select_lex->setup_ref_array(thd, og_num) || |