Bug #4792 lower_case_table_names does not resolve db.tbl.column in SELECT list

sql_base.cc:
  Added code to lowercase database name in insert_fields when lower_case_table_names=1. This fixes bug# 4792

sql/sql_base.cc

@@ -2062,9 +2062,20 @@ bool
 insert_fields(THD *thd,TABLE_LIST *tables, const char *db_name,
 	      const char *table_name, List_iterator<Item> *it)
 {
+  char name_buff[NAME_LEN+1];
   uint found;
   DBUG_ENTER("insert_fields");
 
+
+  if (db_name && lower_case_table_names)
+  {
+    /* convert database to lower case for comparison */
+    strmake( name_buff, db_name, sizeof(name_buff)-1 );
+    casedn_str( name_buff );
+    db_name = name_buff;
+  }
+
+
   found=0;
   for (; tables ; tables=tables->next)
   {