增加(insert)

1. INSERT INTO STUDENT(`NAME`) VALUES ('赵六')
2. INSERT INTO STUDENT  SET NAME='胡歌'

1：支持多条插入与子查询

INSERT INTO STUDENT(`NAME`) 
SELECT CNAME 
FROM COURSE
WHERE CID=1

修改(update)

UPDATE STUDENT S LEFT JOIN COURSE C ON S.CID=C.CID 
SET S.NAME='江疏影'
WHERE S.ID=6 

删除(delete)

1. delete from  表名  where    条件
2. truncate table 表名

区别：