奇怪的sql复合语句问题(php+mysql)
$userid = 123;
$sql = "INSERT INTO tmp(user_id,result) SELECT user_id,result FROM user_exam WHERE user_id=$userid GROUP BY result";
if (!mysql_query($sql, $db))
{
echo "error!";
exit;
}
每次执行总是输出error,但在phpmyadmin中直接执行是可以的:
INSERT INTO tmp(user_id,result) SELECT user_id,result FROM user_exam WHERE user_id=123 GROUP BY result
数据库肯定是连接好了的,因为这段语句前面还有几个sql都正确执行了
不解,求教