如果SQL中有group by, 判断group by 的条件是哪一张表的。当group by 来自于多张表,则不做处理。只有当group by 的条件都来自于同一张表,或者这张表是驱动表则将返回这张表,否则返回NULL
| 773 | |
| 774 | //如果SQL中有group by, 判断group by 的条件是哪一张表的。当group by 来自于多张表,则不做处理。只有当group by 的条件都来自于同一张表,或者这张表是驱动表则将返回这张表,否则返回NULL |
| 775 | TABLE_LIST* mysql_sql_parse_group() { |
| 776 | TABLE_LIST * table = NULL; |
| 777 | bool is_only_one_table = true; |
| 778 | SQL_I_List<ORDER> group_list = current_lex->group_list; |
| 779 | if (group_list.elements > 0) { |
| 780 | if (options.verbose) |
| 781 | sql_print_information("第%d步：开始解析group by 条件 \n", STEP_CNT++); |
| 782 | ORDER *order_field = group_list.first; |
| 783 | while (order_field != NULL) { |
| 784 | if (order_field->item_ptr->type() == Item::FIELD_ITEM) { |
| 785 | TABLE_LIST * tbname2 = find_table( |
| 786 | (Item_field *) (order_field->item_ptr)); |
| 787 | if (tbname2 == NULL) { |
| 788 | is_only_one_table = false; |
| 789 | break; |
| 790 | } else { |
| 791 | if (table == NULL) { |
| 792 | table = tbname2; |
| 793 | } else if (table->table_name != tbname2->table_name) { |
| 794 | is_only_one_table = false; |
| 795 | break; |
| 796 | } |
| 797 | } |
| 798 | } |
| 799 | order_field = order_field->next; |
| 800 | } |
| 801 | |
| 802 | if (is_only_one_table) { |
| 803 | if (TABLE_ELEMENT == 1 || table->is_table_driverd) { |
| 804 | return table; |
| 805 | } |
| 806 | } |
| 807 | } |
| 808 | return NULL; |
| 809 | } |
| 810 | |
| 811 | //同理,同时判断order by 表是否相同,还要判断升降序是否一致 |
| 812 | TABLE_LIST* mysql_sql_parse_order() { |
no test coverage detected