mysql查询错误 FUNCTION nvl does not exist

mysql 中没有nvl ()函数,使用ifnull代替，示例如下:

mysql> SELECT ifnull(sum(P.PAYMONEY),0) totalmoney  FROM jc_pay P;
±-----------+
| totalmoney |
±-----------+
|          0 |
±-----------+
1 row in set

mysql> SELECT nvl(sum(P.PAYMONEY),0) totalmoney  FROM jc_pay P;
1305 - FUNCTION hb.nvl does not exist
mysql>