标签：sel ali form this hat 删除 des names limit
mysql> show databases -> ; +--------------------+ | Database | +--------------------+ | information_schema | | alarms | | dashboard | | falcon_portal | | graph | | mysql | | oldboydb | | performance_schema | | uic | | zabbix | +--------------------+ 10 rows in set (0.00 sec) mysql> use oldboydb; Reading table information for completion of table and column names You can turn off this feature to get a quicker startup with -A Database changed mysql> mysql> mysql> mysql> show tables; +--------------------+ | Tables_in_oldboydb | +--------------------+ | student | +--------------------+ 1 row in set (0.00 sec) 增加数据 mysql> insert into student(name,age,register_date) values("JiaLiu",5,"2018-06-20"); Query OK, 1 row affected (0.01 sec) mysql> insert into student(name,age,register_date) values("JiaLiu",8,"2018-06-20"); Query OK, 1 row affected (0.00 sec) mysql> select * from student; +----+----------+-----+---------------+ | id | name | age | register_date | +----+----------+-----+---------------+ | 1 | ZhanYang | 3 | 2018-06-20 | | 2 | JiaLiu | 30 | 2018-06-20 | | 3 | JiaLiu | 5 | 2018-06-20 | | 4 | JiaLiu | 8 | 2018-06-20 | +----+----------+-----+---------------+ 4 rows in set (0.00 sec) 查找数据 mysql> select * from student offset 2; ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '2' at line 1 mysql> select * from student limit 2; +----+----------+-----+---------------+ | id | name | age | register_date | +----+----------+-----+---------------+ | 1 | ZhanYang | 3 | 2018-06-20 | | 2 | JiaLiu | 30 | 2018-06-20 | +----+----------+-----+---------------+ 2 rows in set (0.00 sec) mysql> select * from student limit 2 offset 1; +----+--------+-----+---------------+ | id | name | age | register_date | +----+--------+-----+---------------+ | 2 | JiaLiu | 30 | 2018-06-20 | | 3 | JiaLiu | 5 | 2018-06-20 | +----+--------+-----+---------------+ 2 rows in set (0.00 sec) mysql> select * from student limit 2 offset 2; +----+--------+-----+---------------+ | id | name | age | register_date | +----+--------+-----+---------------+ | 3 | JiaLiu | 5 | 2018-06-20 | | 4 | JiaLiu | 8 | 2018-06-20 | +----+--------+-----+---------------+ 2 rows in set (0.00 sec) mysql> select * from student where id>3 -> ; +----+--------+-----+---------------+ | id | name | age | register_date | +----+--------+-----+---------------+ | 4 | JiaLiu | 8 | 2018-06-20 | +----+--------+-----+---------------+ 1 row in set (0.01 sec) mysql> select * from student where id>3 and age<20; +----+--------+-----+---------------+ | id | name | age | register_date | +----+--------+-----+---------------+ | 4 | JiaLiu | 8 | 2018-06-20 | +----+--------+-----+---------------+ 1 row in set (0.00 sec) mysql> insert into student(name,age,register_date) values("JiaLiu",8,"2018-04-20"); Query OK, 1 row affected (0.01 sec) mysql> insert into student(name,age,register_date) values("JiaLiu",50,"2018-05-20"); Query OK, 1 row affected (0.00 sec) mysql> insert into student(name,age,register_date) values("JiaLiu",40,"2018-09-20"); Query OK, 1 row affected (0.01 sec) mysql> desc student; +---------------+----------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +---------------+----------+------+-----+---------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | name | char(32) | NO | | NULL | | | age | int(11) | NO | | NULL | | | register_date | date | NO | | NULL | | +---------------+----------+------+-----+---------+----------------+ 4 rows in set (0.00 sec) mysql> selent * from student; ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'selent * from student' at line 1 mysql> selent * from student; ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'selent * from student' at line 1 mysql> select * from student; +----+----------+-----+---------------+ | id | name | age | register_date | +----+----------+-----+---------------+ | 1 | ZhanYang | 3 | 2018-06-20 | | 2 | JiaLiu | 30 | 2018-06-20 | | 3 | JiaLiu | 5 | 2018-06-20 | | 4 | JiaLiu | 8 | 2018-06-20 | | 5 | JiaLiu | 8 | 2018-04-20 | | 6 | JiaLiu | 50 | 2018-05-20 | | 7 | JiaLiu | 40 | 2018-09-20 | +----+----------+-----+---------------+ 7 rows in set (0.00 sec) mysql> select * from student where register_date like "2018-06%"; +----+----------+-----+---------------+ | id | name | age | register_date | +----+----------+-----+---------------+ | 1 | ZhanYang | 3 | 2018-06-20 | | 2 | JiaLiu | 30 | 2018-06-20 | | 3 | JiaLiu | 5 | 2018-06-20 | | 4 | JiaLiu | 8 | 2018-06-20 | +----+----------+-----+---------------+ 4 rows in set, 1 warning (0.00 sec) 改表数据 mysql> update student set name="LiuJia",age=33 where id=4; Query OK, 1 row affected (0.10 sec) Rows matched: 1 Changed: 1 Warnings: 0 mysql> select * from student; +----+----------+-----+---------------+ | id | name | age | register_date | +----+----------+-----+---------------+ | 1 | ZhanYang | 3 | 2018-06-20 | | 2 | JiaLiu | 30 | 2018-06-20 | | 3 | JiaLiu | 5 | 2018-06-20 | | 4 | LiuJia | 33 | 2018-06-20 | | 5 | JiaLiu | 8 | 2018-04-20 | | 6 | JiaLiu | 50 | 2018-05-20 | | 7 | JiaLiu | 40 | 2018-09-20 | +----+----------+-----+---------------+ 7 rows in set (0.00 sec) mysql> 删除数据： mysql> select * from student; +----+----------+-----+---------------+ | id | name | age | register_date | +----+----------+-----+---------------+ | 1 | ZhanYang | 3 | 2018-06-20 | | 2 | JiaLiu | 30 | 2018-06-20 | | 3 | JiaLiu | 5 | 2018-06-20 | | 4 | LiuJia | 33 | 2018-06-20 | | 5 | JiaLiu | 8 | 2018-04-20 | | 6 | JiaLiu | 50 | 2018-05-20 | | 7 | JiaLiu | 40 | 2018-09-20 | +----+----------+-----+---------------+ 7 rows in set (0.00 sec) mysql> delete from student where name="JiaLiu"; Query OK, 5 rows affected (0.01 sec) mysql> select * from student; +----+----------+-----+---------------+ | id | name | age | register_date | +----+----------+-----+---------------+ | 1 | ZhanYang | 3 | 2018-06-20 | | 4 | LiuJia | 33 | 2018-06-20 | +----+----------+-----+---------------+ 2 rows in set (0.00 sec) mysql> 排序： 升序 指定id mysql> select * from student order by id; +----+----------+-----+---------------+ | id | name | age | register_date | +----+----------+-----+---------------+ | 1 | ZhanYang | 3 | 2018-06-20 | | 4 | LiuJia | 33 | 2018-06-20 | +----+----------+-----+---------------+ 2 rows in set (0.00 sec) 降序 mysql> select * from student order by id desc; +----+----------+-----+---------------+ | id | name | age | register_date | +----+----------+-----+---------------+ | 4 | LiuJia | 33 | 2018-06-20 | | 1 | ZhanYang | 3 | 2018-06-20 | +----+----------+-----+---------------+ 2 rows in set (0.00 sec) mysql> 统计分组： 通过NAME分组: mysql> select name,count(*) from student group by name; +----------+----------+ | name | count(*) | +----------+----------+ | gaoyf | 1 | | JiaLiu | 2 | | LiuJia | 1 | | ZhanYang | 1 | | zhouha | 1 | | zhujh | 1 | +----------+----------+ 6 rows in set (0.00 sec) 使用注册日期分组： mysql> select register_date ,count(*) from student group by register_date ; +---------------+----------+ | register_date | count(*) | +---------------+----------+ | 2018-04-20 | 4 | | 2018-05-30 | 1 | | 2018-06-20 | 2 | +---------------+----------+ 3 rows in set (0.00 sec) 将count设置别名为stu_num： mysql> select register_date ,count(*) as stu_num from student group by register_date ; +---------------+---------+ | register_date | stu_num | +---------------+---------+ | 2018-04-20 | 4 | | 2018-05-30 | 1 | | 2018-06-20 | 2 | +---------------+---------+ 3 rows in set (0.00 sec) mysql> SUM 统计总和，这里是统计年龄总和： mysql> select name ,sum(age) from student; +----------+----------+ | name | sum(age) | +----------+----------+ | ZhanYang | 17948 | +----------+----------+ 1 row in set (0.00 sec) mysql> mysql> select name ,sum(age) from student group by name ; +----------+----------+ | name | sum(age) | +----------+----------+ | gaoyf | 8898 | | JiaLiu | 8903 | | LiuJia | 33 | | ZhanYang | 3 | | zhouha | 22 | | zhujh | 89 | +----------+----------+ 6 rows in set (0.00 sec) mysql> select name ,sum(age) from student group by name with rollup; +----------+----------+ | name | sum(age) | +----------+----------+ | gaoyf | 8898 | | JiaLiu | 8903 | | LiuJia | 33 | | ZhanYang | 3 | | zhouha | 22 | | zhujh | 89 | | NULL | 17948 | +----------+----------+ 7 rows in set (0.01 sec) mysql> mysql> select coalesce(name ,sum(age)) from student group by name with rollup; +--------------------------+ | coalesce(name ,sum(age)) | +--------------------------+ | gaoyf | | JiaLiu | | LiuJia | | ZhanYang | | zhouha | | zhujh | | 17948 | +--------------------------+ 7 rows in set (0.00 sec) mysql>标签：sel ali form this hat 删除 des names limit
原文地址：http://blog.51cto.com/zhanx/2153495
