mysql 关于大小写

SELECT * FROM S WHERE sid=1111;
SELECT * FROM s WHERE sid=1111;
SELECT * FROM S WHERE Sid=1111;
SELECT * FROM s WHERE Sid=1111;
select * FROM S WHERE sid=1111;
select * FROM s WHERE sid=1111;
select * FROM S WHERE Sid=1111;
select * FROM s WHERE Sid=1111;

结果均为

 

 s表如下