【收藏】常用SQL语句

//MySQL 5.1参考手册

CREATE TABLE pet (name VARCHAR(20), owner VARCHAR(20),
species VARCHAR(20), sex CHAR(1), birth DATE, death DATE); //创建表

mysql> show tables;  //查看数据库中的表
+----------------+
| Tables_in_test |
+----------------+
| pet            |
+----------------+
1 row in set (0.00 sec)

mysql> describe pet;  //查看表的结构
+---------+-------------+------+-----+---------+-------+
| Field   | Type        | Null | Key | Default | Extra |
+---------+-------------+------+-----+---------+-------+
| name    | varchar(20) | YES  |     | NULL    |       |
| owner   | varchar(20) | YES  |     | NULL    |       |
| species | varchar(20) | YES  |     | NULL    |       |
| sex     | char(1)     | YES  |     | NULL    |       |
| birth   | date        | YES  |     | NULL    |       |
| death   | date        | YES  |     | NULL    |       |
+---------+-------------+------+-----+---------+-------+
6 rows in set (0.00 sec)

//导入txt文件中的数据
LOAD DATA LOCAL INFILE 'E:\\pet.txt' INTO TABLE pet;  //导入txt文件中的数据
load data local infile 'E:\\data.txt' into table pet; 

mysql> INSERT INTO pet
    -> VALUES ('Puffball','Diane','hamster','f','1999-03-30',NULL);  //一次导入一条数据
Query OK, 1 row affected (0.40 sec)

mysql> select * from pet where name='bowser';   //查询name=XxxxX的数据
+--------+-------+---------+------+------------+------------+
| name   | owner | species | sex  | birth      | death      |
+--------+-------+---------+------+------------+------------+
| bowser | diane | dog     | m    | 1979-08-31 | 1995-07-29 |
+--------+-------+---------+------+------------+------------+
1 row in set (0.00 sec)

mysql> select * from pet where birth>'1998-1-1';  //查询birth在1998-1-1之后的数据
+----------+-------+---------+------+------------+-------+
| name     | owner | species | sex  | birth      | death |
+----------+-------+---------+------+------------+-------+
| chirpy   | gwen  | bird    | f    | 1998-09-11 | NULL  |
| Puffball | Diane | hamster | f    | 1999-03-30 | NULL  |
+----------+-------+---------+------+------------+-------+
2 rows in set (0.00 sec)

mysql> select * from pet where species='dog' and sex='f';  //组合条件的使用
+-------+--------+---------+------+------------+-------+
| name  | owner  | species | sex  | birth      | death |
+-------+--------+---------+------+------------+-------+
| buffy | harold | dog     | f    | 1989-05-13 | NULL  |
+-------+--------+---------+------+------------+-------+
1 row in set (0.00 sec)

mysql> select * from pet where species='dog' or species='bird';  //or操作符，满足一个条件即可
+----------+--------+---------+------+------------+------------+
| name     | owner  | species | sex  | birth      | death      |
+----------+--------+---------+------+------------+------------+
| buffy    | harold | dog     | f    | 1989-05-13 | NULL       |
| fang     | benny  | dog     | m    | 1990-08-27 | NULL       |
| bowser   | diane  | dog     | m    | 1979-08-31 | 1995-07-29 |
| chirpy   | gwen   | bird    | f    | 1998-09-11 | NULL       |
| whistler | gwen   | bird    |      | 1997-12-09 | NULL       |
+----------+--------+---------+------+------------+------------+
5 rows in set (0.00 sec)

mysql> select * from pet where (species='cat' and sex='m')   //and、or混用
    -> or (species='dog' and sex='f');
+-------+--------+---------+------+------------+-------+
| name  | owner  | species | sex  | birth      | death |
+-------+--------+---------+------+------------+-------+
| claws | gwen   | cat     | m    | 1994-03-17 | NULL  |
| buffy | harold | dog     | f    | 1989-05-13 | NULL  |
+-------+--------+---------+------+------------+-------+
2 rows in set (0.00 sec)

mysql> select name,birth from pet;  //输出制定的字段内容
+----------+------------+
| name     | birth      |
+----------+------------+
| fluff    | 1993-02-04 |
| claws    | 1994-03-17 |
| buffy    | 1989-05-13 |
| fang     | 1990-08-27 |
| bowser   | 1979-08-31 |
| chirpy   | 1998-09-11 |
| whistler | 1997-12-09 |
| slim     | 1996-04-29 |
| Puffball | 1999-03-30 |
+----------+------------+
9 rows in set (0.00 sec)

mysql> select distinct owner from pet;  //对输出的字段做去重处理
+--------+
| owner  |
+--------+
| harold |
| gwen   |
| benny  |
| diane  |
+--------+
4 rows in set (0.00 sec)

mysql> select name,birth from pet order by birth;  //对birth排序，默认升序
+----------+------------+
| name     | birth      |
+----------+------------+
| bowser   | 1979-08-31 |
| buffy    | 1989-05-13 |
| fang     | 1990-08-27 |
| fluff    | 1993-02-04 |
| claws    | 1994-03-17 |
| slim     | 1996-04-29 |
| whistler | 1997-12-09 |
| chirpy   | 1998-09-11 |
| Puffball | 1999-03-30 |
+----------+------------+
9 rows in set (0.00 sec)

mysql> select name,birth from pet order by birth desc; //降序排列，最小值放第一个位置
+----------+------------+
| name     | birth      |
+----------+------------+
| Puffball | 1999-03-30 |
| chirpy   | 1998-09-11 |
| whistler | 1997-12-09 |
| slim     | 1996-04-29 |
| claws    | 1994-03-17 |
| fluff    | 1993-02-04 |
| fang     | 1990-08-27 |
| buffy    | 1989-05-13 |
| bowser   | 1979-08-31 |
+----------+------------+
9 rows in set (0.00 sec)

mysql> select name,species,birth from pet order by species,birth desc; //对多列排序，一个升序一个降序
+----------+---------+------------+
| name     | species | birth      |
+----------+---------+------------+
| chirpy   | bird    | 1998-09-11 |
| whistler | bird    | 1997-12-09 |
| claws    | cat     | 1994-03-17 |
| fluff    | cat     | 1993-02-04 |
| fang     | dog     | 1990-08-27 |
| buffy    | dog     | 1989-05-13 |
| bowser   | dog     | 1979-08-31 |
| Puffball | hamster | 1999-03-30 |
| slim     | snake   | 1996-04-29 |
+----------+---------+------------+
9 rows in set (0.00 sec)

//计算年龄
mysql> select name,birth,curdate(),  //当前日期
    -> (year(curdate())-year(birth))-(right(curdate(),5)<right(birth,5))   //这里还是有一些不理解，后面慢慢研究
    -> as age  //字段重命名为age
    -> from pet;
+----------+------------+------------+------+
| name     | birth      | curdate()  | age  |
+----------+------------+------------+------+
| fluff    | 1993-02-04 | 2016-10-30 |   23 |
| claws    | 1994-03-17 | 2016-10-30 |   22 |
| buffy    | 1989-05-13 | 2016-10-30 |   27 |
| fang     | 1990-08-27 | 2016-10-30 |   26 |
| bowser   | 1979-08-31 | 2016-10-30 |   37 |
| chirpy   | 1998-09-11 | 2016-10-30 |   18 |
| whistler | 1997-12-09 | 2016-10-30 |   18 |
| slim     | 1996-04-29 | 2016-10-30 |   20 |
| Puffball | 1999-03-30 | 2016-10-30 |   17 |
+----------+------------+------------+------+
9 rows in set (0.00 sec)

//针对rigth做的解释案例
mysql> select curdate();  //当前日期，格式为2016-10-30
+------------+
| curdate()  |
+------------+
| 2016-10-30 |
+------------+

mysql> select right(curdate(),5);   //取后边5个字符，如此可以让年龄计算更加的精确
+--------------------+
| right(curdate(),5) |
+--------------------+
| 10-30              |
+--------------------+

mysql> select name,birth,curdate(),
    -> (year(curdate())-year(birth))-(right(curdate(),5)<right(birth,5))
    -> as age
    -> from pet
    -> order by age;   //按照年龄排序，age是字段的别称
+----------+------------+------------+------+
| name     | birth      | curdate()  | age  |
+----------+------------+------------+------+
| Puffball | 1999-03-30 | 2016-10-30 |   17 |
| chirpy   | 1998-09-11 | 2016-10-30 |   18 |
| whistler | 1997-12-09 | 2016-10-30 |   18 |
| slim     | 1996-04-29 | 2016-10-30 |   20 |
| claws    | 1994-03-17 | 2016-10-30 |   22 |
| fluff    | 1993-02-04 | 2016-10-30 |   23 |
| fang     | 1990-08-27 | 2016-10-30 |   26 |
| buffy    | 1989-05-13 | 2016-10-30 |   27 |
| bowser   | 1979-08-31 | 2016-10-30 |   37 |
+----------+------------+------------+------+
9 rows in set (0.00 sec)

mysql> select name,birth,death,
    -> (year(death)-year(birth))-(right(death,5)< right(birth,5))  //计算已死亡年数
    -> as age
    -> from pet where death is not null order by age;    抓取不为空的数据
+--------+------------+------------+------+
| name   | birth      | death      | age  |
+--------+------------+------------+------+
| bowser | 1979-08-31 | 1995-07-29 |   15 |
+--------+------------+------------+------+
1 row in set (0.00 sec)

mysql> select name,birth,month(birth) from pet;   /出生月份
+----------+------------+--------------+
| name     | birth      | month(birth) |
+----------+------------+--------------+
| fluff    | 1993-02-04 |            2 |
| claws    | 1994-03-17 |            3 |
| buffy    | 1989-05-13 |            5 |
| fang     | 1990-08-27 |            8 |
| bowser   | 1979-08-31 |            8 |
| chirpy   | 1998-09-11 |            9 |
| whistler | 1997-12-09 |           12 |
| slim     | 1996-04-29 |            4 |
| Puffball | 1999-03-30 |            3 |
+----------+------------+--------------+
9 rows in set (0.01 sec)

mysql> select name,birth from pet
    -> where month(birth)=month(date_add(curdate(),interval 2 month));
    //在当前月份的基础上加2个月，得到月份是当前月份+2的数据
+----------+------------+
| name     | birth      |
+----------+------------+
| whistler | 1997-12-09 |
+----------+------------+
1 row in set (0.00 sec)

“_”匹配任何单个字符，
“%”匹配任意数目字符(包括零字符)

mysql> select * from pet where name like 'b%';   //查找name以字母b开头的数据
+--------+--------+---------+------+------------+------------+
| name   | owner  | species | sex  | birth      | death      |
+--------+--------+---------+------+------------+------------+
| buffy  | harold | dog     | f    | 1989-05-13 | NULL       |
| bowser | diane  | dog     | m    | 1979-08-31 | 1995-07-29 |
+--------+--------+---------+------+------------+------------+
2 rows in set (0.00 sec)

mysql> select * from pet where name like '%fy';  //查找以fy结尾的数据
+-------+--------+---------+------+------------+-------+
| name  | owner  | species | sex  | birth      | death |
+-------+--------+---------+------+------------+-------+
| buffy | harold | dog     | f    | 1989-05-13 | NULL  |
+-------+--------+---------+------+------------+-------+
1 row in set (0.02 sec)

mysql> select * from pet where name like '%w%';  //查找name中包含了w字母的数据
+----------+-------+---------+------+------------+------------+
| name     | owner | species | sex  | birth      | death      |
+----------+-------+---------+------+------------+------------+
| claws    | gwen  | cat     | m    | 1994-03-17 | NULL       |
| bowser   | diane | dog     | m    | 1979-08-31 | 1995-07-29 |
| whistler | gwen  | bird    |      | 1997-12-09 | NULL       |
+----------+-------+---------+------+------------+------------+
3 rows in set (0.00 sec)

mysql> select * from pet where name like '_____';  //查找name正好包含5个字母的数据
+-------+--------+---------+------+------------+-------+
| name  | owner  | species | sex  | birth      | death |
+-------+--------+---------+------+------------+-------+
| fluff | harold | cat     | f    | 1993-02-04 | NULL  |
| claws | gwen   | cat     | m    | 1994-03-17 | NULL  |
| buffy | harold | dog     | f    | 1989-05-13 | NULL  |
+-------+--------+---------+------+------------+-------+
3 rows in set (0.00 sec)

‘.’匹配任何单个的字符。
[...]：匹配在方括号内的任何字符。
例如，“[abc]”匹配“a”、“b”或“c”。为了命名字符的范围，使用一个“-”。
[a-z]：匹配任何字母
[0-9]：匹配任何数字
“ * ”匹配零个或多个在它前面的字符。
例如，“x*”匹配任何数量的“x”字符，“[0-9]*”匹配任何数量的数字，而“.*”匹配任何数量的任何字符。
“^”：开头
“$”：结尾

mysql> select * from pet where name regexp '^b';  //查找以模式字母b开始的数据
+--------+--------+---------+------+------------+------------+
| name   | owner  | species | sex  | birth      | death      |
+--------+--------+---------+------+------------+------------+
| buffy  | harold | dog     | f    | 1989-05-13 | NULL       |
| bowser | diane  | dog     | m    | 1979-08-31 | 1995-07-29 |
+--------+--------+---------+------+------------+------------+
2 rows in set (0.00 sec)

mysql> select * from pet where name regexp 'fy$';  //查找以模式字母fy结尾的数据
+-------+--------+---------+------+------------+-------+
| name  | owner  | species | sex  | birth      | death |
+-------+--------+---------+------+------------+-------+
| buffy | harold | dog     | f    | 1989-05-13 | NULL  |
+-------+--------+---------+------+------------+-------+
1 row in set (0.00 sec)

mysql> select * from pet where name regexp 'w';  //正则查找包含字母w的数据
+----------+-------+---------+------+------------+------------+
| name     | owner | species | sex  | birth      | death      |
+----------+-------+---------+------+------------+------------+
| claws    | gwen  | cat     | m    | 1994-03-17 | NULL       |
| bowser   | diane | dog     | m    | 1979-08-31 | 1995-07-29 |
| whistler | gwen  | bird    |      | 1997-12-09 | NULL       |
+----------+-------+---------+------+------------+------------+
3 rows in set (0.00 sec)

mysql> select * from pet where name regexp '^.{5}$';  //查找name正好包含5个字母的数据
//正则的方式
+-------+--------+---------+------+------------+-------+
| name  | owner  | species | sex  | birth      | death |
+-------+--------+---------+------+------------+-------+
| fluff | harold | cat     | f    | 1993-02-04 | NULL  |
| claws | gwen   | cat     | m    | 1994-03-17 | NULL  |
| buffy | harold | dog     | f    | 1989-05-13 | NULL  |
+-------+--------+---------+------+------------+-------+
3 rows in set (0.00 sec)

mysql> select count(*) from pet;   //计数行
+----------+
| count(*) |
+----------+
|        9 |
+----------+
1 row in set (0.00 sec)

mysql> select owner,count(*) from pet group by owner;    //分组计数
+--------+----------+
| owner  | count(*) |
+--------+----------+
| benny  |        2 |
| diane  |        2 |
| gwen   |        3 |
| harold |        2 |
+--------+----------+
4 rows in set (0.00 sec)

mysql> select species,sex,count(*) from pet group by species,sex;  //按照species和sex2个条件进行分组
+---------+------+----------+
| species | sex  | count(*) |
+---------+------+----------+
| bird    |      |        1 |
| bird    | f    |        1 |
| cat     | f    |        1 |
| cat     | m    |        1 |
| dog     | f    |        1 |
| dog     | m    |        2 |
| hamster | f    |        1 |
| snake   | m    |        1 |
+---------+------+----------+
8 rows in set (0.00 sec)

mysql> create table event (name varchar(20),date date,  //创建event表，是pet的附表
    -> type varchar(15),remark varchar(255));
Query OK, 0 rows affected (0.60 sec)

//event.txt文件数据：
fluffy    1995/5/15    litter    4 kittens, 3 female, 1 male
buffy    1993/6/23    litter    5 puppies, 2 female, 3 male
buffy    1994/6/19    litter    3 puppies, 3 female
chirpy    1999/3/21    vet    needed beak straightened
slim    1997/8/3    vet    broken rib
bowser    1991/10/12    kennel
fang    1991/10/12    kennel
fang    1998/8/28    birthday    Gave him a new chew toy
claws    1998/3/17    birthday    Gave him a new flea collar
whistler    1998/12/9    birthday    First birthday

mysql> LOAD DATA LOCAL INFILE 'E:\\event.txt' INTO TABLE event;  //转载数据
Query OK, 10 rows affected (0.20 sec)
Records: 10  Deleted: 0  Skipped: 0  Warnings: 0

//
mysql> select pet.name,
    -> (year(date)-year(birth))-(right(date,5)<right(birth,5))  as age,
    -> remark
    -> from pet,event
    -> where pet.name=event.name and event.type='litter';
+-------+------+------------------------------+
| name  | age  | remark                       |
+-------+------+------------------------------+
 |buffy |    4 | 5 puppies, 2 female, 3 male
         |   5 | 3 puppies, 3 female
+-------+------+------------------------------+
2 rows in set (0.00 sec)

mysql> select pet.name,
    -> remark
    -> from pet,event
    -> where pet.name=event.name and event.type='litter';     //联合查找 type='litter'的数据
+-------+------------------------------+
| name  | remark                       |
+-------+------------------------------+
 |buffy | 5 puppies, 2 female, 3 male
         |3 puppies, 3 female
+-------+------------------------------+
2 rows in set (0.00 sec)

mysql> select database();   //查找当前所有数据库，这里特指正在使用的数据库
+------------+
| database() |
+------------+
| test       |
+------------+
1 row in set (0.00 sec)

mysql> show tables;  //查看所有表
+----------------+
| Tables_in_test |
+----------------+
| event          |
| pet            |
+----------------+
2 rows in set (0.00 sec)

mysql>  describe pet;   //查找表的结构
+---------+-------------+------+-----+---------+-------+
| Field   | Type        | Null | Key | Default | Extra |
+---------+-------------+------+-----+---------+-------+
| name    | varchar(20) | YES  |     | NULL    |       |
| owner   | varchar(20) | YES  |     | NULL    |       |
| species | varchar(20) | YES  |     | NULL    |       |
| sex     | char(1)     | YES  |     | NULL    |       |
| birth   | date        | YES  |     | NULL    |       |
| death   | date        | YES  |     | NULL    |       |
+---------+-------------+------+-----+---------+-------+
6 rows in set (0.00 sec)

mysql> create table shop(            //创建shop数据库
    -> article int(4) unsigned zerofill default '' not null,    //指定数字位数，位数不足自动用0补齐
    -> dealer char(20) default '' not null,
    -> price double(16,2) default '0.00' not null,   //price保留2个小数点，16个字节，默认值0.00
    -> primary key(article,dealer));
Query OK, 0 rows affected (0.62 sec)

mysql> insert into  shop values    //插入数据，一种新的插入数据的形式
    -> (1,'a',3.45),
    -> (1,'b',3.99),
    -> (2,'a',10.99),
    -> (3,'b',1045),
    -> (3,'c',1.69),
    -> (3,'d',1.25),
    -> (4,'d',19.95);
Query OK, 7 rows affected (0.40 sec)
Records: 7  Duplicates: 0  Warnings: 0

mysql> select * from shop;   //查看全部数据结果
+---------+--------+---------+
| article | dealer | price   |
+---------+--------+---------+
|    0001 | a      |    3.45 |
|    0001 | b      |    3.99 |
|    0002 | a      |   10.99 |
|    0003 | b      | 1045.00 |
|    0003 | c      |    1.69 |
|    0003 | d      |    1.25 |
|    0004 | d      |   19.95 |
+---------+--------+---------+
7 rows in set (0.00 sec)

mysql> select max(article) as '物品号最大的商品' from shop;    //max
+------------------+
| 物品号最大的商品 |
+------------------+
|                4 |
+------------------+
1 row in set (0.02 sec)

mysql> select article,dealer,price      //查找最贵商品的编号、销售商和价格等数据
    -> from shop
    -> where price=
    -> (select max(price) from shop);    //从子查询语句来实现
+---------+--------+---------+
| article | dealer | price   |
+---------+--------+---------+
|    0003 | b      | 1045.00 |
+---------+--------+---------+
1 row in set (0.00 sec)

mysql> select article,dealer,price      //查找最贵商品的编号、销售商和价格等数据
    -> from shop                        //排序（降序）和limit方式综合实现
    -> order by price desc
    -> limit 1;
+---------+--------+---------+
| article | dealer | price   |
+---------+--------+---------+
|    0003 | b      | 1045.00 |
+---------+--------+---------+
1 row in set (0.00 sec)

mysql> select article,max(price) as price      //分组求每种商品的最大值
    -> from shop
    -> group by article;
+---------+---------+
| article | price   |
+---------+---------+
|    0001 |    3.99 |
|    0002 |   10.99 |
|    0003 | 1045.00 |
|    0004 |   19.95 |
+---------+---------+
4 rows in set (0.35 sec)

mysql> select article,dealer,price   //定义要查找的字段
    -> from shop s1  //数据来源
    -> where price=  //定义数据需要满足的条件
    -> (select max(s2.price) from shop s2 where s1.article = s2.article);
+---------+--------+---------+
| article | dealer | price   |
+---------+--------+---------+
|    0001 | b      |    3.99 |
|    0002 | a      |   10.99 |
|    0003 | b      | 1045.00 |
|    0004 | d      |   19.95 |
+---------+--------+---------+
4 rows in set (0.00 sec)

//论坛用户访问时间数据
mysql> create table t1 (year year(4),month int(2) unsigned zerofill,    //创建t1表
    -> day int(2) unsigned zerofill);
Query OK, 0 rows affected (0.65 sec)

mysql> insert into t1 values   //插入数据
    -> (2000,1,1),
    -> (2000,2,20),
    -> (2000,1,30),
    -> (2000,2,2),
    -> (2000,2,23),
    -> (2000,2,23);
Query OK, 6 rows affected (0.40 sec)
Records: 6  Duplicates: 0  Warnings: 0

ysql> select year,month,bit_count(bit_or(1<<day)) as days   //查找同年同月访问量
    -> from t1
    -> group by year,month;
+------+-------+------+
| year | month | days |
+------+-------+------+
| 2000 |    01 |    2 |
| 2000 |    02 |    3 |    //本来是4次，为什么是3次呢，做了去重处理
+------+-------+------+
2 rows in set (0.36 sec)

mysql> create table animals(         //通过AUTO_INCREMENT属性为新的行产生唯一的标识
    -> id mediumint not null auto_increment,
    -> name char(20) not null,
    -> primary key(id)
    -> );
Query OK, 0 rows affected (0.26 sec)

mysql> insert into animals (name) values
    -> ('dog'),
    -> ('cat'),
    -> ('penguin'),
    -> ('lax'),
    -> ('whale'),
    -> ('ostrich');

mysql> select * from animals;    //通过查看结果可以看出表对name自动加了编号
+----+---------+
| id | name    |
+----+---------+
|  1 | dog     |
|  2 | cat     |
|  3 | penguin |
|  4 | lax     |
|  5 | whale   |
|  6 | ostrich |
+----+---------+
6 rows in set (0.00 sec)

mysql> alter table animals auto_increment=100;   //定义数据的编号从100开始编号
Query OK, 0 rows affected (0.37 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> insert into animals (name) values   //插入一条新的数据
    -> ('cat1');
Query OK, 1 row affected (0.40 sec)

mysql> select * from animals;   //查看发现最新插入的数据编号为100，而不是编号7
+-----+---------+
| id  | name    |
+-----+---------+
|   1 | dog     |
|   2 | cat     |
|   3 | penguin |
|   4 | lax     |
|   5 | whale   |
|   6 | ostrich |
| 100 | cat1    |
+-----+---------+
7 rows in set (0.00 sec)