✌✌✌The ancients have something to say, good memory is not as good as bad writing. A journey of a thousand miles begins with a single step. Thousands of lines of code every day are indispensable. Write a summary every day. Target a big factory. If you are full of hope, you will be invincible, hahaha! ! ! ✌✌✌
1. Title description
2. Answer ideas
> 利用简单的if语句
3. MySql language
update salary
set sex=if(sex='f','m','f')