mysql查询语句集锦介绍

-- 基本查询

select * from pet

-- 列出指定的列

select name, owner form pet

-- 直接进行算术运算，对字段起别名

select sin(1+2) as sin

--where 条件

select * from pet where (birth>'1980' and species='dog') or species='bird'

-- 对null 的条件

select * from pet where sex is not null

-- 所有名字第四位是n 的宠物信息是

select * from pet where owner like '___n%'

-- 所有主人名叫gwen 或benny 的宠物

select * from pet where owner in ('gwen' , 'benny')

-- 查询出生日期在90 年代是宠物，相当与 >= and <=

select * from pet where birth between '1990' and '1999'

-- 按主人姓名排序，相同的按宠物姓名倒序排列

select * from pet order by owner, name desc

-- 查询性别为公的宠物，按生日倒序排列

select * from pet where sex='m' order by birth desc

--char_lenngth() 返回的字符的长度，length() 返回字节长度

SELECT owner,length(owner),char_length(owner) FROM pet p;

-- 列出养有宠物狗的人名

select distinct owner from pet where species='dog'

-- 用两种方法查询出所有狗和猫的名字、出生年份、出生月份

select name, left(birth,4) as year, mid(birth, 6, 2) as month from pet

where species='dog' or species='cat'

select name, year(birth) as year, month(birth) as month from pet

where species in('dog','cat')

-- 查询所有名字中存在字母'e' 的人，将他们养的宠物按类别、年龄排序

select name, species, birth

from pet

where owner like '%e%'

order by species,birth desc

-- 数字函数

select round(2.345,2), truncate(2.345,2), mod(323,5)

-- 日期函数

select now(), curdate(), curtime()

select adddate('2007-02-02', interval 31 day)

-- 求出所有宠物的年龄

select name,birth,

truncate(datediff(now(),birth)/365,0) as age1,

year(now())-year(birth) - (dayofyear(birth)>dayofyear(now())) as age2

from pet

-- 分组函数

select min(birth),max(birth),avg(birth),count(*),count(sex),

sum(birth)

from pet

-- 每种宠物各有几只

select species,count(*)

from pet

group by species

-- 查询年龄最大的宠物的信息

select * from pet where birth =

(select max(birth) from pet)

-- 每年各出生了几只宠物

select year(birth), count(*) from pet group by year(birth)

-- 鸟和猫的性别比例

select species, sex, count(*)

from pet

where species in ('cat','bird')

group by species, sex

-- 各种宠物年龄的和

select species, sum(truncate(datediff(now(),birth)/365,0)) as SumAge

from pet

group by species

-- 数量大于1 的宠物种类

select species, count(*) as c

from pet

group by species

having c>=2

-- 基本双表关联

select a.name,a.species, a.sex,b.date, b.type, b.remark

from pet a,event b

where a.name = b.name

-- 查询宠物产仔时的年龄

select a.name, a.species,

truncate(datediff(b.date,a.birth)/365,0) as age

from pet a,event b

where a.name = b.name and b.type='litter'

--90 年代出生的狗的事件列表

select a.name,birth,species,sex,date,type,remark

from pet a,event b

where a.name=b.name and birth between '1990' and '1999'

and species='dog'

-- 活着的宠物按发生的事件类型分组，看各种事件发生的次数

select type, count(*)

from pet a, event b

where a.name=b.name and a.death is null

group by type

-- 记录的事件数量超过1 条的宠物信息

select a.name,species,sex,count(*)

from pet a, event b

where a.name = b.name

group by b.name

having count(*)>=2

-- 列出发生了两件事情的宠物的事件记录信息

select a.name,type,date,remark,b.species,b.sex,b.owner

from event a, pet b

where a.name=b.name and

b.name in

(

select name

from event

group by name

having count(*)=2

)

-- 插入语句

insert into pet (name,species,birth)

values ('KKK','snake','2007-01-01');

insert into pet

values ('KK','Diane','cat','f',null,null);

insert into pet set name='k',owner='Benny'

-- 更新语句

update pet set species='snake',sex='f',birth=now()

where name='k'

-- 将事件表中生日的日期，更新到pet 表中相应宠物的birth 字段

update pet a

set birth = (

select date

from event b

where a.name=b.name and b.type='birthday'

)

where a.name in (

select name

from event

where type='birthday'

)

-- 删除语句

delete from pet where name like 'k%'

基本查询语句

SELECT * FROM `test` WHERE 1 //简单查询
SELECT id,uid FROM newdb.`test` WHERE 1 //查询ID、UID等字段
SELECT remark as r FROM `test` WHERE 1 //别名查询
SELECT * FROM `test` WHERE id=1,3 //条件查询，相等
SELECT * FROM `test` WHERE id<>2,3 //条件按查，不相等
SELECT * FROM `test` WHERE id in (1,2,4) //in查询，即查询ID为1，2，4的数据
SELECT * FROM `test` WHERE not in (2,3) //in查询，查询ID不是2，3的数据
SELECT * FROM `test` WHERE `uid` like '%王%' //like模糊查询，%*%前后匹配
SELECT * FROM `test` WHERE id BETWEEN 1 and 3 //条件查询，中间数据
SELECT * FROM `test` WHERE id NOT BETWEEN 1and3 //条件查询
SELECT * FROM `test` WHERE id=1 and `remark`='学生' //多个条件
SELECT * FROM `test` group by `remark` //查询排序
SELECT * FROM `test` order by `regdate` ASC //order by升序排序,放到limit之前
SELECT * FROM `test` order by `regdate` ASC,id DESC //order by按照注册时间升序，ID降序
ASC 升序、DESC降序。

SELECT * FROM `test` limit 0,3 //数据条数限制，输出三条
SELECT count(*) FROM `test` WHERE 1 //统计查询，可以查询单个统计，例如count(name)
SELECT max(id) FROM `test` WHERE 1 //统计ID最大值是多少
以下三个和以上max用法类似
MIN(*)最小值函数
AVG(*)平均值函数
SUM(*)累计值函数

基本插入语句：

insert into test (`id`,`uid`,`regdate`,`remark`) values ('','PHP100','2008-07-26','工人')//ID自增，
insert into test (`id`,`uid`,`regdate`,`remark`) values ('','PHP100','now()','工人')
insert into test values ('','PHP200','now()','工人') //简便写法，但不提倡

更新语句：

update test set uid='php200' where id=6 //set 后是要改后的内容。where 后是更改位置

删除语句：

Delete from dbname.`test` where id=3