bk commit into 4.1 tree (gkodinov:1.2538) BUG#22457

[kgeorge]

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ChangeSet@stripped, 2006-11-02 10:48:23+02:00, gkodinov@stripped +3 -0
  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. The however may point not only to Item_field in the select
   list (or to a table column) but also to an arbitrary Item. This causing
   Item_field::fix_fields to throw an error about missing column.
   Fixed by substituting the Item_field for the reference with an Item_ref
   when not pointing to Item_field.

  mysql-test/r/order_by.result@stripped, 2006-11-02 10:48:18+02:00, gkodinov@stripped +11 -0
    Bug #22457: Column alias in ORDER BY works, but not if in an expression
     - test case

  mysql-test/t/order_by.test@stripped, 2006-11-02 10:48:19+02:00, gkodinov@stripped +9 -0
    Bug #22457: Column alias in ORDER BY works, but not if in an expression
     - test case

  sql/item.cc@stripped, 2006-11-02 10:48:19+02:00, gkodinov@stripped +29 -3
    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

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	gkodinov
# Host:	macbook.gmz
# Root:	/Users/kgeorge/mysql/work/B22457-4.1-opt

--- 1.233/sql/item.cc	2006-09-25 15:24:04 +03:00
+++ 1.234/sql/item.cc	2006-11-02 10:48:19 +02:00
@@ -1761,10 +1761,36 @@
         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)
         {
-          set_field((*((Item_field**)res))->field);
-          return 0;
+          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 plug that
+              instead of the Item_field made by the parser.
+            */
+            Item_ref *rf= new Item_ref(db_name,table_name,field_name);
+            if (!rf)
+              return 1;
+            thd->change_item_tree(ref, rf);
+            /*
+              rf is Item_ref => never substitute other items (in this case)
+              during fix_fields() => we can use rf after fix_fields()
+             */
+            return rf->fix_fields(thd, tables, ref) ||  rf->check_cols(1);
+          }
         }
       }
 

--- 1.47/mysql-test/r/order_by.result	2006-04-21 08:15:34 +03:00
+++ 1.48/mysql-test/r/order_by.result	2006-11-02 10:48:18 +02:00
@@ -820,3 +820,14 @@
 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
+DROP TABLE t1;

--- 1.34/mysql-test/t/order_by.test	2006-04-21 08:15:34 +03:00
+++ 1.35/mysql-test/t/order_by.test	2006-11-02 10:48:19 +02:00
@@ -559,4 +559,13 @@
 
 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);
+DROP TABLE t1;
+
 # End of 4.1 tests