处理unsigned相减错误(BIGINT UNSIGNED value is out of range)
mysql 当两个字段想减时,如果其中一个或两个字段的类型的unsigned无签名类型,如果想减的值小于0则会报错(BIGINT UNSIGNED value is out of range)
测试:
select cast(1 as unsigned)-2
select 0-cast(1 as unsigned)
解决办法:
一、修改字段类型
二、使用cast函数转字段为signed类型
select cast(1 as signed)-2