MDEV-8913 Derived queries with same column names as final projection …

…causes issues when using Order By

find_item_in_list() now recognize view fields like a fields even if they rever to an expression.
The problem of schema name do not taken into account for field with it and
derived table fixed.
Duplicating code removed

mysql-test/r/view.result

@@ -5699,6 +5699,47 @@ idAlbum	strAlbum	strMusicBrainzAlbumID	strArtists	strGenres	iYear	strMoods	strSt
 1	strAlbum1	strMusicBrainzAlbumID1	strArtists1	strGenres1	2000	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	0	0	album	1	1	strArtist1	strMusicBrainzArtistID	0		0
 drop view v1,v2;
 drop table t1,t2,t3,t4;
+#
+# MDEV-8913: Derived queries with same column names as final
+# projection causes issues when using Order By
+#
+create table t1 (field int);
+insert into t1 values (10),(5),(3),(8),(20);
+SELECT sq.f2 AS f1, sq.f1 AS f2
+FROM ( SELECT field AS f1, 1 AS f2 FROM t1) AS sq
+ORDER BY sq.f1;
+f1	f2
+1	3
+1	5
+1	8
+1	10
+1	20
+create view v1 as SELECT field AS f1, 1 AS f2 FROM t1;
+SELECT sq.f2 AS f1, sq.f1 AS f2
+FROM v1 AS sq
+ORDER BY sq.f1;
+f1	f2
+1	3
+1	5
+1	8
+1	10
+1	20
+drop view v1;
+create table t2 SELECT field AS f1, 1 AS f2 FROM t1;
+SELECT
+sq.f2 AS f1,
+sq.f1 AS f2
+FROM t2 AS sq
+ORDER BY sq.f1;
+f1	f2
+1	3
+1	5
+1	8
+1	10
+1	20
+drop table t1, t2;
+SELECT 1 FROM (SELECT 1 as a) AS b HAVING (SELECT `SOME_GARBAGE`.b.a)=1;
+ERROR 42S22: Unknown column 'SOME_GARBAGE.b.a' in 'field list'
 # -----------------------------------------------------------------
 # -- End of 10.0 tests.
 # -----------------------------------------------------------------

mysql-test/t/view.test

@@ -5602,6 +5602,38 @@ SELECT v1.*,v2.* FROM v1 LEFT JOIN v2 ON v1.idAlbum = v2.idAlbum WHERE v1.idAlbu
 drop view v1,v2;
 drop table t1,t2,t3,t4;
 
+--echo #
+--echo # MDEV-8913: Derived queries with same column names as final
+--echo # projection causes issues when using Order By
+--echo #
+create table t1 (field int);
+insert into t1 values (10),(5),(3),(8),(20);
+
+SELECT sq.f2 AS f1, sq.f1 AS f2
+FROM ( SELECT field AS f1, 1 AS f2 FROM t1) AS sq
+ORDER BY sq.f1;
+
+create view v1 as SELECT field AS f1, 1 AS f2 FROM t1;
+
+SELECT sq.f2 AS f1, sq.f1 AS f2
+FROM v1 AS sq
+ORDER BY sq.f1;
+
+drop view v1;
+
+create table t2 SELECT field AS f1, 1 AS f2 FROM t1;
+
+SELECT
+  sq.f2 AS f1,
+  sq.f1 AS f2
+FROM t2 AS sq
+ORDER BY sq.f1;
+
+drop table t1, t2;
+
+--error ER_BAD_FIELD_ERROR
+SELECT 1 FROM (SELECT 1 as a) AS b HAVING (SELECT `SOME_GARBAGE`.b.a)=1; 
+
 --echo # -----------------------------------------------------------------
 --echo # -- End of 10.0 tests.
 --echo # -----------------------------------------------------------------

sql/sql_base.cc

@@ -6423,6 +6423,7 @@ find_field_in_table_ref(THD *thd, TABLE_LIST *table_list,
       */
       table_name && table_name[0] &&
       (my_strcasecmp(table_alias_charset, table_list->alias, table_name) ||
+       (db_name && db_name[0] && (!table_list->db || !table_list->db[0])) ||
        (db_name && db_name[0] && table_list->db && table_list->db[0] &&
         (table_list->schema_table ?
          my_strcasecmp(system_charset_info, db_name, table_list->db) :
@@ -6896,7 +6897,10 @@ find_item_in_list(Item *find, List<Item> &items, uint *counter,
 
   for (uint i= 0; (item=li++); i++)
   {
-    if (field_name && item->real_item()->type() == Item::FIELD_ITEM)
+    if (field_name &&
+        (item->real_item()->type() == Item::FIELD_ITEM ||
+         ((item->type() == Item::REF_ITEM) &&
+          (((Item_ref *)item)->ref_type() == Item_ref::VIEW_REF))))
     {
       Item_ident *item_field= (Item_ident*) item;
 
@@ -7022,35 +7026,6 @@ find_item_in_list(Item *find, List<Item> &items, uint *counter,
         break;
       }
     }
-    else if (table_name && item->type() == Item::REF_ITEM &&
-             ((Item_ref *)item)->ref_type() == Item_ref::VIEW_REF)
-    {
-      /*
-        TODO:Here we process prefixed view references only. What we should 
-        really do is process all types of Item_refs. But this will currently 
-        lead to a clash with the way references to outer SELECTs (from the 
-        HAVING clause) are handled in e.g. :
-        SELECT 1 FROM t1 AS t1_o GROUP BY a
-          HAVING (SELECT t1_o.a FROM t1 AS t1_i GROUP BY t1_i.a LIMIT 1).
-        Processing all Item_refs here will cause t1_o.a to resolve to itself.
-        We still need to process the special case of Item_direct_view_ref 
-        because in the context of views they have the same meaning as 
-        Item_field for tables.
-      */
-      Item_ident *item_ref= (Item_ident *) item;
-      if (field_name && item_ref->name && item_ref->table_name &&
-          !my_strcasecmp(system_charset_info, item_ref->name, field_name) &&
-          !my_strcasecmp(table_alias_charset, item_ref->table_name,
-                         table_name) &&
-          (!db_name || (item_ref->db_name && 
-                        !strcmp (item_ref->db_name, db_name))))
-      {
-        found= li.ref();
-        *counter= i;
-        *resolution= RESOLVED_IGNORING_ALIAS;
-        break;
-      }
-    }
   }
   if (!found)
   {