diff options
Diffstat (limited to 'sql/item.cc')
| -rw-r--r-- | sql/item.cc | 50 |
1 files changed, 39 insertions, 11 deletions
diff --git a/sql/item.cc b/sql/item.cc index 9551c5feaff..0ebb1d61a28 100644 --- a/sql/item.cc +++ b/sql/item.cc @@ -6853,14 +6853,21 @@ void resolve_const_item(THD *thd, Item **ref, Item *comp_item) } /** - Return true if the value stored in the field is equal to the const - item. + Compare the value stored in field, with the original item. - We need to use this on the range optimizer because in some cases - we can't store the value in the field without some precision/character loss. + @param field field which the item is converted and stored in + @param item original item + + @return Return an integer greater than, equal to, or less than 0 if + the value stored in the field is greater than, equal to, + or less than the original item + + @note We only use this on the range optimizer/partition pruning, + because in some cases we can't store the value in the field + without some precision/character loss. */ -bool field_is_equal_to_item(Field *field,Item *item) +int stored_field_cmp_to_item(Field *field, Item *item) { Item_result res_type=item_cmp_type(field->result_type(), @@ -6871,28 +6878,49 @@ bool field_is_equal_to_item(Field *field,Item *item) char field_buff[MAX_FIELD_WIDTH]; String item_tmp(item_buff,sizeof(item_buff),&my_charset_bin),*item_result; String field_tmp(field_buff,sizeof(field_buff),&my_charset_bin); + enum_field_types field_type; item_result=item->val_str(&item_tmp); if (item->null_value) - return 1; // This must be true + return 0; field->val_str(&field_tmp); - return !stringcmp(&field_tmp,item_result); + + /* + If comparing DATE with DATETIME, append the time-part to the DATE. + So that the strings are equally formatted. + A DATE converted to string is 10 characters, and a DATETIME converted + to string is 19 characters. + */ + field_type= field->type(); + if (field_type == MYSQL_TYPE_DATE && + item_result->length() == 19) + field_tmp.append(" 00:00:00"); + else if (field_type == MYSQL_TYPE_DATETIME && + item_result->length() == 10) + item_result->append(" 00:00:00"); + + return stringcmp(&field_tmp,item_result); } if (res_type == INT_RESULT) - return 1; // Both where of type int + return 0; // Both are of type int if (res_type == DECIMAL_RESULT) { my_decimal item_buf, *item_val, field_buf, *field_val; item_val= item->val_decimal(&item_buf); if (item->null_value) - return 1; // This must be true + return 0; field_val= field->val_decimal(&field_buf); - return !my_decimal_cmp(item_val, field_val); + return my_decimal_cmp(item_val, field_val); } double result= item->val_real(); if (item->null_value) + return 0; + double field_result= field->val_real(); + if (field_result < result) + return -1; + else if (field_result > result) return 1; - return result == field->val_real(); + return 0; } Item_cache* Item_cache::get_cache(const Item *item) |