A fix (bug #7281: RAND(RAND) crashes server).

mysql-test/r/func_math.result

@@ -124,3 +124,5 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 Warnings:
 Note	1003	select degrees(pi()) AS `degrees(pi())`,radians(360) AS `radians(360)`
+select rand(rand);
+ERROR 42S22: Unknown column 'rand' in 'field list'

mysql-test/t/func_math.test

@@ -51,3 +51,10 @@ SELECT ASIN(1.2-0.2);
 #select floor(log(16)/log(2));
 
 explain extended select degrees(pi()),radians(360);
+
+#
+# Bug #7281: problem with rand()
+#
+
+--error 1054
+select rand(rand);

sql/item_func.cc

@@ -1091,7 +1091,8 @@ double Item_func_round::val()
 bool Item_func_rand::fix_fields(THD *thd, struct st_table_list *tables,
                                 Item **ref)
 {
-  Item_real_func::fix_fields(thd, tables, ref);
+  if (Item_real_func::fix_fields(thd, tables, ref))
+    return TRUE;
   used_tables_cache|= RAND_TABLE_BIT;
   if (arg_count)
   {					// Only use argument once in query