MDEV-18605: Loss of column aliases by using view and group

Preserv column name with copy fields even if it is function and Co.

mysql-test/main/view.result

@@ -6705,5 +6705,27 @@ drop table t1;
 ALTER VIEW IF NOT EXISTS v1 AS SELECT 1;
 ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'IF NOT EXISTS v1 AS SELECT 1' at line 1
 #
+# MDEV-18605: Loss of column aliases by using view and group
+#
+CREATE TABLE t1 (id int, foo int);
+CREATE VIEW v1 AS  SELECT id, IFNULL(foo,'') AS foo FROM t1;
+INSERT INTO t1 (id, foo) VALUES (1,1),(2,2);
+SELECT v.id, v.foo AS bar  FROM v1 v
+WHERE id = 2;
+id	bar
+2	2
+SELECT v.id, v.foo AS bar  FROM v1 v
+GROUP BY v.id;
+id	bar
+1	1
+2	2
+SELECT v.id, v.foo AS bar  FROM v1 v
+WHERE id = 2
+GROUP BY v.id;
+id	bar
+2	2
+Drop View v1;
+Drop table t1;
+#
 # End of 10.3 tests
 #

mysql-test/main/view.test

@@ -6414,6 +6414,29 @@ drop table t1;
 --error ER_PARSE_ERROR
 ALTER VIEW IF NOT EXISTS v1 AS SELECT 1;
 
+--echo #
+--echo # MDEV-18605: Loss of column aliases by using view and group
+--echo #
+
+CREATE TABLE t1 (id int, foo int);
+CREATE VIEW v1 AS  SELECT id, IFNULL(foo,'') AS foo FROM t1;
+
+INSERT INTO t1 (id, foo) VALUES (1,1),(2,2);
+
+SELECT v.id, v.foo AS bar  FROM v1 v
+  WHERE id = 2;
+
+SELECT v.id, v.foo AS bar  FROM v1 v
+  GROUP BY v.id;
+
+SELECT v.id, v.foo AS bar  FROM v1 v
+  WHERE id = 2
+  GROUP BY v.id;
+
+#Cleanup
+Drop View v1;
+Drop table t1;
+
 --echo #
 --echo # End of 10.3 tests
 --echo #

sql/sql_select.cc

@@ -23914,7 +23914,9 @@ setup_copy_fields(THD *thd, TMP_TABLE_PARAM *param,
 	      real_pos->type() == Item::COND_ITEM) &&
 	     !real_pos->with_sum_func)
     {						// Save for send fields
+      LEX_CSTRING real_name= pos->name;
       pos= real_pos;
+      pos->name= real_name;
       /* TODO:
 	 In most cases this result will be sent to the user.
 	 This should be changed to use copy_int or copy_real depending