mysql报错BIGINT UNSIGNED value is out of range

执行如下语句报错:

select * from table_name
where a - b > 100;

其中a,b字段类型都为int(10) unsigned

解决方案:

使用cast(a as signed)语法将字段转换为signed. 最终语句如下:

select * from table_name
CAST(a as signed) - CAST(b as signed) > 100