容易忘记的sql语句

--增加索引 me是索引的名字
ALTER  TABLE product add index   me(fuck)

--删除列
ALTER  TABLE product DROP  fuck

--增加列
ALTER  TABLE product add  fuck1 int NOT NULL

--解释
EXPLAIN  SELECT * FROM product where id =1
--简单查询 两者是一样的
select * FROM users where gender="男" GROUP BY school
select * FROM users GROUP BY school HAVING gender='男'

 
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