因为2个时间在数据库里设计的都是无符号,但是使用结束时间-开始时间=负数,所以报错
今天在做一个功能的时候,用到两个时间戳相减来做查询条件,由于其两个字段都是unsigned的,并两个的大小是不一样。所以直接相减查询的时候, 就出现ERROR 1690 (22003): BIGINT UNSIGNED value is out of range in..的错误,因为结果可能会出现负数。。。。 过后查资料,发现可以通过下面的方法来解决: mysql> select lastvisit, lastactivity from pre_common_member_status limit 1; +------------+--------------+ | lastvisit | lastactivity | +------------+--------------+ | 1199200260 | 1198336989 | +------------+--------------+ 1 row in set (0.01 sec) mysql> select lastvisit-lastactivity from pre_common_member_status limit 1; +------------------------+ | lastvisit-lastactivity | +------------------------+ | 863271 | +------------------------+ 1 row in set (0.05 sec) mysql> select abs(lastvisit-lastactivity) from pre_common_member_status limit 1; +-----------------------------+ | abs(lastvisit-lastactivity) | +-----------------------------+ | 863271 | +-----------------------------+ 1 row in set (0.03 sec) mysql> select lastactivity-lastvisit from pre_common_member_status limit 1; ERROR 1690 (22003): BIGINT UNSIGNED value is out of range in '(`discuz`.`pre_c ommon_member_status`.`lastactivity` - `discuz`.`pre_common_member_status`.`las tvisit`)' mysql> select cast(lastactivity as signed)-cast(lastvisit as signed) from pre_co mmon_member_status limit 1; +--------------------------------------------------------+ | cast(lastactivity as signed)-cast(lastvisit as signed) | +--------------------------------------------------------+ | -863271 | +--------------------------------------------------------+ 1 row in set (0.02 sec) mysql> select abs(cast(lastactivity as signed)-cast(lastvisit as signed)) from p re_common_member_status limit 1; +-------------------------------------------------------------+ | abs(cast(lastactivity as signed)-cast(lastvisit as signed)) | +-------------------------------------------------------------+ | 863271 | +-------------------------------------------------------------+ 1 row in set (0.00 sec) mysql>