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MySQL插入 更新与删掉数据

发布时间:2022-07-01 11:04:35 所属栏目:MySql教程 来源:互联网
导读:存储在系统中的数据是数据库管理系统(DBMS)的核心,数据库被设计用来管理数据的存储、访问和维护数据的完整性。MySQL中提供丰富的数据管理语句,包括插入数据的INSERT、更新数据的UPDATE以及删除数据的DELETE语句。 1、插入数据 为表的所有字段插入数据 使
   存储在系统中的数据是数据库管理系统(DBMS)的核心,数据库被设计用来管理数据的存储、访问和维护数据的完整性。MySQL中提供丰富的数据管理语句,包括插入数据的INSERT、更新数据的UPDATE以及删除数据的DELETE语句。
 
  1、插入数据
 
  为表的所有字段插入数据
 
   使用基本的INSERT语句插入数据,要求指定表名称和插入到新纪录中的值,其基本语法为:
 
  INSERT INTO tbl_name (column_list) VALUES (value_list)
  在插入数据前,首先创建一张表:
 
  mysql> CREATE TABLE person
      -> (
      -> id     INT UNSIGNED NOT NULL AUTO_INCREMENT,
      -> name   CHAR(40) NOT NULL DEFAULT '',
      -> age    INT NOT NULL DEFAULT 0,
      -> info   CHAR(50) NULL,
      -> PRIMARY KEY (id)
      -> );
  Query OK, 0 rows affected (0.03 sec)
  在person表中,插入一条新记录,id值为1,name值为Green,age值为21,info值为Lawyer
 
  mysql>  INSERT INTO person (id ,name, age , info)
      ->       VALUES (1,'Green', 21, 'Lawyer');
  Query OK, 1 row affected (0.02 sec)
 
  mysql> SELECT * FROM person;
  +----+-------+-----+--------+
  | id | name  | age | info   |
  +----+-------+-----+--------+
  |  1 | Green |  21 | Lawyer |
  +----+-------+-----+--------+
  1 row in set (0.00 sec)
  在person表中,插入一条新记录,id值为2,name值为Suse,age值为22,info值为dancer
 
  mysql>  INSERT INTO person (age ,name, id , info)
      ->       VALUES (22, 'Suse', 2, 'dancer');
  Query OK, 1 row affected (0.02 sec)
 
  mysql> SELECT * FROM person;
  +----+-------+-----+--------+
  | id | name  | age | info   |
  +----+-------+-----+--------+
  |  1 | Green |  21 | Lawyer |
  |  2 | Suse  |  22 | dancer |
  +----+-------+-----+--------+
  2 rows in set (0.00 sec)
  为表的指定字段插入数据
 
  在person表中,插入一条新记录,name值为Willam,age值为20,info值为sports man
 
  mysql>  INSERT INTO person (name, age,info)
      ->      VALUES('Willam', 20, 'sports man');
  Query OK, 1 row affected (0.02 sec)
 
  mysql> SELECT * FROM person;                                                       
  +----+--------+-----+------------+
  | id | name   | age | info       |
  +----+--------+-----+------------+
  |  1 | Green  |  21 | Lawyer     |
  |  2 | Suse   |  22 | dancer     |
  |  3 | Willam |  20 | sports man |
  +----+--------+-----+------------+
  3 rows in set (0.00 sec)
  在person表中,插入一条新记录,name值为laura,age值为25
 
  mysql>  INSERT INTO person (name, age ) VALUES ('Laura', 25);
  Query OK, 1 row affected (0.01 sec)
 
  mysql> SELECT * FROM person;                                 
  +----+--------+-----+------------+
  | id | name   | age | info       |
  +----+--------+-----+------------+
  |  1 | Green  |  21 | Lawyer     |
  |  2 | Suse   |  22 | dancer     |
  |  3 | Willam |  20 | sports man |
  |  4 | Laura  |  25 | NULL       |
  +----+--------+-----+------------+
  4 rows in set (0.00 sec)
    可以发现id字段在插入数据后,没有赋值时自动增加,在这里id字段为表的主键,不能为空,紫铜会自动为字段插入自增的序列值。
 
  同时插入多条记录
 
    INSERT语句可以同时相数据表中插入多条记录,插入时指定多个值列表,每个值列表之间用逗号分隔开,基本语法为:
 
  INSERT INTO tbl_name (column_list)
    VALUES (value_list1), (value_list2),(value_list3);
  在person表中,在name、age和info字段指定插入值,同时插入3条新记录
 
  mysql>  INSERT INTO person(name, age, info)
      ->      VALUES ('Evans',27, 'secretary'),
      ->      ('Dale',22, 'cook'),
      ->      ('Edison',28, 'singer');
  Query OK, 3 rows affected (0.02 sec)
  Records: 3  Duplicates: 0  Warnings: 0
 
  mysql> SELECT * FROM person;                                                              
  +----+--------+-----+------------+
  | id | name   | age | info       |
  +----+--------+-----+------------+
  |  1 | Green  |  21 | Lawyer     |
  |  2 | Suse   |  22 | dancer     |
  |  3 | Willam |  20 | sports man |
  |  4 | Laura  |  25 | NULL       |
  |  5 | Evans  |  27 | secretary  |
  |  6 | Dale   |  22 | cook       |
  |  7 | Edison |  28 | singer     |
  +----+--------+-----+------------+
  7 rows in set (0.00 sec)
  在person表中,不指定插入列表,同时插入2条新记录
 
  mysql>  INSERT INTO person
      ->      VALUES (9,'Harry',21, 'magician'),
      ->      (NULL,'Harriet',19, 'pianist');
  Query OK, 2 rows affected (0.02 sec)
  Records: 2  Duplicates: 0  Warnings: 0
 
  mysql> SELECT * FROM person;                                                              
  +----+---------+-----+------------+
  | id | name    | age | info       |
  +----+---------+-----+------------+
  |  1 | Green   |  21 | Lawyer     |
  |  2 | Suse    |  22 | dancer     |
  |  3 | Willam  |  20 | sports man |
  |  4 | Laura   |  25 | NULL       |
  |  5 | Evans   |  27 | secretary  |
  |  6 | Dale    |  22 | cook       |
  |  7 | Edison  |  28 | singer     |
  |  9 | Harry   |  21 | magician   |
  | 10 | Harriet |  19 | pianist    |
  +----+---------+-----+------------+
  9 rows in set (0.00 sec)
  将查询结果插入数据
 
   INSERT语句用来给数据表插入记录时,指定插入记录的列值。INSERT还可以将SELECT语句查询的结果插入到列表中,其基本语法为:
 
  INSERT INTO tbl_name1 (column_list1)
    SELECT (column_list2) FROM table_name2 WHERE (condition)
  从person_old表中查询所有的记录,并将其插入到person表中
 
  首先,创建一个名为person_old的数据表,其表结构与person结构相同
  mysql> CREATE TABLE person_old
      -> (
      -> id     INT UNSIGNED NOT NULL AUTO_INCREMENT,
      -> name   CHAR(40) NOT NULL DEFAULT '',
      -> age    INT NOT NULL DEFAULT 0,
      -> info   CHAR(50) NULL,
      -> PRIMARY KEY (id)
      -> );
  Query OK, 0 rows affected (0.11 sec)
 
  向person_old表中添加两条记录
  mysql>  INSERT INTO person_old
      ->      VALUES (11,'Harry',20, 'student'), (12,'Beckham',31, 'police');
  Query OK, 2 rows affected (0.20 sec)
  Records: 2  Duplicates: 0  Warnings: 0
 
  mysql> SELECT * FROM person_old;
  +----+---------+-----+---------+
  | id | name    | age | info    |
  +----+---------+-----+---------+
  | 11 | Harry   |  20 | student |
  | 12 | Beckham |  31 | police  |
  +----+---------+-----+---------+
  2 rows in set (0.00 sec)
 
  插入数据到person表中
  mysql> INSERT INTO person(id, name, age, info)
      ->      SELECT id, name, age, info FROM person_old;
  Query OK, 2 rows affected (0.01 sec)
  Records: 2  Duplicates: 0  Warnings: 0
 
  mysql> SELECT * FROM person;
  +----+---------+-----+------------+
  | id | name    | age | info       |
  +----+---------+-----+------------+
  |  1 | Green   |  21 | Lawyer     |
  |  2 | Suse    |  22 | dancer     |
  |  3 | Willam  |  20 | sports man |
  |  4 | Laura   |  25 | NULL       |
  |  5 | Evans   |  27 | secretary  |
  |  6 | Dale    |  22 | cook       |
  |  7 | Edison  |  28 | singer     |
  |  9 | Harry   |  21 | magician   |
  | 10 | Harriet |  19 | pianist    |
  | 11 | Harry   |  20 | student    |
  | 12 | Beckham |  31 | police     |
  +----+---------+-----+------------+
  11 rows in set (0.00 sec)
  2、更新数据
 
    表中有数据之后,可以对数据进行更新,其基本语法为:
 
  UPDATE table_name
      SET col_name1=value1,col_name2=value2,...,
      WHERE where_condition
  在person表中,更新id值为11的记录,将age字段值改为15,将name字段值改为LiMing
 
  mysql> UPDATE person SET age = 15, name='LiMing' WHERE id = 11;
  Query OK, 1 row affected (0.02 sec)
  Rows matched: 1  Changed: 1  Warnings: 0
 
  mysql> SELECT * FROM person WHERE id=11;
  +----+--------+-----+---------+
  | id | name   | age | info    |
  +----+--------+-----+---------+
  | 11 | LiMing |  15 | student |
  +----+--------+-----+---------+
  1 row in set (0.00 sec)
  在person表中,更新age值为19~22的记录,将info字段值都改为student
 
  mysql> UPDATE person SET info='student'  WHERE age  BETWEEN 19 AND 22;  
  Query OK, 6 rows affected (0.02 sec)
  Rows matched: 6  Changed: 6  Warnings: 0
 
  mysql> SELECT * FROM person WHERE age BETWEEN 19 AND 22;                 
  +----+---------+-----+---------+
  | id | name    | age | info    |
  +----+---------+-----+---------+
  |  1 | Green   |  21 | student |
  |  2 | Suse    |  22 | student |
  |  3 | Willam  |  20 | student |
  |  6 | Dale    |  22 | student |
  |  9 | Harry   |  21 | student |
  | 10 | Harriet |  19 | student |
  +----+---------+-----+---------+
  6 rows in set (0.00 sec)
  3、删除数据
 
    从数据表中删除数据使用DELETE语句,其基本语法为:
 
  DELETE FROMN table_name [WHERE <condition>]
  在person表中,删除id等于11的记录
 
  执行删除操作前,使用SELECT语句查看当前id=11的记录
  mysql>  SELECT * FROM person WHERE id=11;
  +----+--------+-----+---------+
  | id | name   | age | info    |
  +----+--------+-----+---------+
  | 11 | LiMing |  15 | student |
  +----+--------+-----+---------+
  1 row in set (0.00 sec)
 
  使用DELETE语句删除该记录
  mysql>  DELETE FROM person WHERE id = 11;
  Query OK, 1 row affected (0.02 sec)
 
  语句执行完毕,查看执行结果:
  mysql>  SELECT * FROM person WHERE id=11;
  Empty set (0.00 sec)
  在person表中,使用DELETE语句同时删除多条记录,删除age字段在19-22的记录
 
  执行删除操作前,使用SELECT语句查看当前的数据
  mysql>  SELECT * FROM person WHERE age BETWEEN 19 AND 22;
  +----+---------+-----+---------+
  | id | name    | age | info    |
  +----+---------+-----+---------+
  |  1 | Green   |  21 | student |
  |  2 | Suse    |  22 | student |
  |  3 | Willam  |  20 | student |
  |  6 | Dale    |  22 | student |
  |  9 | Harry   |  21 | student |
  | 10 | Harriet |  19 | student |
  +----+---------+-----+---------+
  6 rows in set (0.00 sec)
 
  DELETE删除这些记录
  mysql>  DELETE FROM person WHERE age BETWEEN 19 AND 22;
  Query OK, 6 rows affected (0.01 sec)
 
  查看执行结果
  mysql>  SELECT * FROM person WHERE age BETWEEN 19 AND 22;
  Empty set (0.00 sec)
  删除person表中所有记录,SQL语句如下
 
  执行删除操作前,使用SELECT语句查看当前的数据:
   mysql> SELECT * FROM person;
  +----+---------+-----+-----------+
  | id | name    | age | info      |
  +----+---------+-----+-----------+
  |  4 | Laura   |  25 | NULL      |
  |  5 | Evans   |  27 | secretary |
  |  7 | Edison  |  28 | singer    |
  | 12 | Beckham |  31 | police    |
  +----+---------+-----+-----------+
  4 rows in set (0.00 sec)
 
  执行DELETE语句删除这4条记录
  mysql>  DELETE FROM person;
  Query OK, 4 rows affected (0.01 sec)
 
  查看执行结果:
  mysql>  SELECT * FROM person;
  Empty set (0.00 sec)
    如果想删除表中的所有记录,还可以使用TRUNCATE TABLE语句,TRUNCATE将直接删除原来的表并重新创建一个表,其语法结构为TRUNCATE TABLE table_name。TRUNCATE直接删除表而不是删除记录,因此执行速度比DELETE快。

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