Commit c095f98f authored by unknown's avatar unknown
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Bug #22457: Column alias in ORDER BY works, but not if in an expression 

 The parser is allocating Item_field for references by name in ORDER BY
 expressions. Such expressions however may point not only to Item_field 
 in the select list (or to a table column) but also to an arbitrary Item. 
 This causes Item_field::fix_fields to throw an error about missing 
 column.
 The fix substitutes Item_field for the reference with an Item_ref when 
 not pointing to Item_field.


mysql-test/r/order_by.result:
  Bug #22457: Column alias in ORDER BY works, but not if in an expression
   - test case
mysql-test/t/order_by.test:
  Bug #22457: Column alias in ORDER BY works, but not if in an expression
   - test case
sql/item.cc:
  Bug #22457: Column alias in ORDER BY works, but not if in an expression
   - transform the Item_field made by the parser into Item_ref if it 
     doesn't point to Item_field and it is in allowed context
parent 5701d8ee

mysql-test/r/order_by.result

+27 −0
Original line number Diff line number Diff line
@@ -820,3 +820,30 @@ b a 
20	1

10	2

DROP TABLE t1;

CREATE TABLE t1 (a INT);

INSERT INTO t1 VALUES (1),(2);

SELECT a + 1 AS num FROM t1 ORDER BY 30 - num;

num

3

2

SELECT CONCAT('test', a) AS str FROM t1 ORDER BY UPPER(str);

str

test1

test2

SELECT a + 1 AS num FROM t1 GROUP BY 30 - num;

num

3

2

SELECT a + 1 AS num FROM t1 HAVING 30 - num;

num

2

3

SELECT a + 1 AS num, num + 1 FROM t1;

ERROR 42S22: Unknown column 'num' in 'field list'

SELECT a + 1 AS num, (select num + 2 FROM t1 LIMIT 1) FROM t1;

num	(select num + 2 FROM t1 LIMIT 1)

2	4

3	5

SELECT a.a + 1 AS num FROM t1 a JOIN t1 b ON num = b.a;

ERROR 42S22: Unknown column 'num' in 'on clause'

DROP TABLE t1;

mysql-test/t/order_by.test

+16 −0
Original line number Diff line number Diff line
@@ -559,4 +559,20 @@ INSERT INTO t1 VALUES (1,30), (2,20), (1,10), (2,30), (1,20), (2,10); 


DROP TABLE t1;



#

# Bug #22457: Column alias in ORDER BY works, but not if in an expression

#



CREATE TABLE t1 (a INT); INSERT INTO t1 VALUES (1),(2);

SELECT a + 1 AS num FROM t1 ORDER BY 30 - num;

SELECT CONCAT('test', a) AS str FROM t1 ORDER BY UPPER(str);

SELECT a + 1 AS num FROM t1 GROUP BY 30 - num;

SELECT a + 1 AS num FROM t1 HAVING 30 - num;

--error 1054

SELECT a + 1 AS num, num + 1 FROM t1;

SELECT a + 1 AS num, (select num + 2 FROM t1 LIMIT 1) FROM t1;

--error 1054

SELECT a.a + 1 AS num FROM t1 a JOIN t1 b ON num = b.a;

DROP TABLE t1;



# End of 4.1 tests

sql/item.cc

+30 −3
Original line number Diff line number Diff line
@@ -1761,11 +1761,38 @@ bool Item_field::fix_fields(THD *thd, TABLE_LIST *tables, Item **ref) 
        Item** res= find_item_in_list(this, thd->lex->current_select->item_list,

                                      &counter, REPORT_EXCEPT_NOT_FOUND,

                                      &not_used);

        if (res != (Item **)not_found_item && (*res)->type() == Item::FIELD_ITEM)

        if (res != (Item **)not_found_item)

        {

          if ((*res)->type() == Item::FIELD_ITEM)

          {

            /*

             It's an Item_field referencing another Item_field in the select

             list.

             use the field from the Item_field in the select list and leave

             the Item_field instance in place.

            */

            set_field((*((Item_field**)res))->field);

            return 0;

          }

          else

          {

            /*

              It's not an Item_field in the select list so we must make a new

              Item_ref to point to the Item in the select list and replace the

              Item_field created by the parser with the new Item_ref.

            */

            Item_ref *rf= new Item_ref(db_name,table_name,field_name);

            if (!rf)

              return 1;

            thd->change_item_tree(ref, rf);

            /*

              Because Item_ref never substitutes itself with other items 

              in Item_ref::fix_fields(), we can safely use the original 

              pointer to it even after fix_fields()

             */

            return rf->fix_fields(thd, tables, ref) ||  rf->check_cols(1);

          }

        }

      }



      /*