mysql如何根据字段1与字段2的差值按照降序排序

如：表table,两字段：c1,c2,我想select * from table ，条件是c1与c2的差值按照降序排序,求指点

那你应该还有一列用来放两者的差值啊；假设这一列叫 c3;
ALTER TABLE 表名 ADD c3 INT IDENTITY NOT NULL;
select c3=c1-c2 from table
order by c3 desc

select c1,c2,(c1-c2) as col2 from table order by col2

select c1,c2, (c1-c2) as diff from table order by diff desc;