MySQL中数据表的增操作_MySQL

今天学习到表的增操作，写个博客总结一下，PS:下面所有的注释都是我在电脑上全部操作完成后，再复制到记事本上添加的。至于在执行的时候可不可以那样添加注释，就有待考证了。

选择库

mysql> show databases;#查看目前有哪些数据库存在+--------------------+| Database           |+--------------------+| information_schema || ceshi_ku           || mysql              || performance_schema |+--------------------+4 rows in set (0.00 sec)mysql> use ceshi_ku;#选择该数据库，等下用来建表，貌似选择数据库可以不要"；"Reading table information for completion of table and column namesYou can turn off this feature to get a quicker startup with -ADatabase changed

建表

mysql> create table biao    -> (    -> id int,    -> name char(10),    -> gender char(2),    -> gongsi char(15),    -> gongzi float    -> );#先建立一个简单的表，编号、名字、性别、公司、工资，建表目前不是重点，是方便接下来的操作Query OK, 0 rows affected (0.13 sec)mysql> select * from biao;#查看表中的内容，目前是空表Empty set (0.00 sec)

插入数据（全部列，多行）

mysql> insert into biao#选择要插入哪张表    -> (id,name,gender,gongsi,gongzi)#往哪些列里面插入内容    -> values#接下来开始插入3条，分别用","隔开，最后一个用";"    -> (1,'ma yun','n','tao bao',6000.5),#把要插入内容依次写好，不可调换顺序！要一一对应    -> (2,'xiao hong','v','xin lang',5000.7),    -> (3,'xiao ming','n','bai du',3000.4);Query OK, 3 rows affected (0.08 sec)Records: 3  Duplicates: 0  Warnings: 0mysql> select * from biao;#查看表中的内容，现在会发现多了3行+------+-----------+--------+----------+--------+| id   | name      | gender | gongsi   | gongzi |+------+-----------+--------+----------+--------+|    1 | ma yun    | n      | tao bao  | 6000.5 ||    2 | xiao hong | v      | xin lang | 5000.7 ||    3 | xiao ming | n      | bai du   | 3000.4 |+------+-----------+--------+----------+--------+3 rows in set (0.01 sec)

插入数据（缺省列，单行）

mysql> insert into biao#这次没有指定往哪些列里面插入，没指定就是往所有列插入    -> values    -> (4,'li si','n','sou hu',9000.2);#这次是只插入一行，也可以插入多行，只需用","隔开Query OK, 1 row affected (0.07 sec)mysql> select * from biao;#查看表内容，会发现比上次多了一行+------+-----------+--------+----------+--------+| id   | name      | gender | gongsi   | gongzi |+------+-----------+--------+----------+--------+|    1 | ma yun    | n      | tao bao  | 6000.5 ||    2 | xiao hong | v      | xin lang | 5000.7 ||    3 | xiao ming | n      | bai du   | 3000.4 ||    4 | li si     | n      | sou hu   | 9000.2 |+------+-----------+--------+----------+--------+4 rows in set (0.00 sec)

插入数据（指定列，多行）

mysql> insert into biao    -> (id,name,gongsi,gongzi)#这次不是往所有列插入，而是部分列    -> values    -> (5,'lao wang','wang yi',1000.5),#依次写好便可，记得对应关系，    -> (6,'xiao li','ku gou',700.1);Query OK, 2 rows affected (0.15 sec)Records: 2  Duplicates: 0  Warnings: 0mysql> select * from biao;#查看表内容，这次会上次发现多了2行，但是"gender"是空的+------+-----------+--------+----------+--------+| id   | name      | gender | gongsi   | gongzi |+------+-----------+--------+----------+--------+|    1 | ma yun    | n      | tao bao  | 6000.5 ||    2 | xiao hong | v      | xin lang | 5000.7 ||    3 | xiao ming | n      | bai du   | 3000.4 ||    4 | li si     | n      | sou hu   | 9000.2 ||    5 | lao wang  | NULL   | wang yi  | 1000.5 ||    6 | xiao li   | NULL   | ku gou   |  700.1 |+------+-----------+--------+----------+--------+6 rows in set (0.00 sec)