Mysql DML language, add, delete, change

DML language

Database manipulation language

• Insert: insert
• Modify: update
• Delete: delete

Insert statement (a)

• grammar

  • INSERT INTO 表名(列名,...)
    VALUES
    (值,...),
    ...
    

• Examples

  • INSERT INTO beauty (name,sex,borndate,phone,photo,boyfriend_id)
    VALUES ('小泽玛利亚','女','1980-1-1',12345678901,null,1);
    

• How to insert null

  • Direct insert null
  • Omit the column name

• Feature

  • Multiple rows of data may be inserted
  • Subqueries

Insert statement (b)

• grammar

  • INSERT INTO 表名
    SET 列名=值, 列名=值...
    

• Feature

  • Only a single row of data may be inserted

Modification statements

Data table amendments

• grammar

  • UPDATE 表名
    SET 列=新值,列=新值,...
    WHERE 筛选条件;
    

Multi-table modify records

• grammar

  • 92 syntax

  • UPDATE 表1 别名,表2 别名
    SET 列=值,...
    WHERE 连接条件
    AND 筛选条件;
    

  • 99 grammar

  • UPDATE 表1 别名
    连接类型 JOIN 表2 别名
    ON 连接条件
    SET 列=值
    WHERE 筛选条件;
    

Delete statement

DELETE

• grammar

  • To delete a single table

  • DELETE FROM 表名 WHERE 筛选条件
    

  • Multi-table delete

    • 92 syntax

    • DELETE 表1的别名,表2的别名
      FROM 表1 别名,表2 别名
      WHERE 连接条件
      AND 筛选条件;
      

    • 99 grammar

    • DELETE 表1的别名,表2的别名
      FROM 表1 别名
      连接条件 JOIN 表2 别名
      WHERE 筛选条件;
      

TRUNCATE

• grammar

  • TRUNCATE TABLE 表名;
    # 直接删除表中的所有数据
    

  • Can not add where condition

  • Can not be rolled back