sql 的一些语句总结

/× 创建一个数据库*/
CREATE DATABASE Drug ON PRIMARY
(
NAME='Drug',
FILENAME='D:\Drug.mdf',
SIZE=3027KB,
MAXSIZE=UNLIMITED,
FILEGROWTH=1024KB
)
LOG ON
(
NAME='Drug_LOG',
FILENAME='D:\Drug.ldf',
SIZE=1024,
FILEGROWTH=10%
)

USE[Drug]
GO

/×创建一个用户表*/
CREATE TABLE userinfo
(
id int identity(1,1) ,/×自增长列*/
name varchar(20),
pwd nvarchar(16),
sex char(5) ,
address nvarchar(50) ,
phone nvarchar(20) ,
plity varchar(10) ,
)

/×创建一个成绩表*/
create table score
(
id int identity(1,1) not null,
u_id int not null,
score int,
)

/×设置创建的表中一些字段的约束*/

alter table userinfo add constraint pk_userinfo primary key(id)/×创建id为userinfo表的主键——-注意:此括号内没有单引号*/
alter table score add constraint pk_score primary key(id)/×创建id为score表的主键*/

alter table userinfo add constraint df_userinfo default('True')for sex /×sex字段默认值为True:男 注意后面的 for 字段名*/
alter table userinfo add constraint ck_userinfo check(len(pwd ) between 6 and 16)/×pwd字段必须在6-16之间的————————检查约束 之间用and表示,而不是&&*/
alter table userinfo add constraint uk_userinfo unique (name) /×name字段设置为唯一————- 注意:此括号内没有单引号*/
alter table score add constraint fk_score foreign key(u_id) references userinfo (id)/×创建id为score表的外键*/
alter table userinfo alter column name varchar(20) not null /×创建或添加字段name 并且不能为空*/
alter table userinfo alter column pwd nvarchar(16) not null
alter table userinfo alter column sex char(5) not null
alter table userinfo alter column address nvarchar(50) not null
alter table userinfo alter column phone nvarchar(20) not null
alter table userinfo alter column plity varchar(10) not null

/×向表中插入一些数据*/
insert into userinfo
([name],pwd, sex,address,phone, plity) values
('zhaoliu','123dfd999','True','江苏省无锡市','15658789123','党员')

——模糊查询
select * from userinfo where username like 's%'
select * from userinfo where username like '%1'
select * from userinfo where username like 's%1'
select * from userinfo where username like '[a-z]%'
select * from userinfo where username like '[a-z0-9]%'
select * from userinfo where username like '[^a-z0-9]%'

/×在表中查询一些数据*/
select * from userinfo

select * from userinfo where name like '%张%'

select count(*) as '数量' from userinfo

select name from userinfo

select name,sex from userinfo

select name+address+'乡' as '个人信息' from userinfo

select name+address+'乡' as '个人信息' from userinfo where name+address+'乡' is not null

select name+address+'乡' as '个人信息' from userinfo where len(phone)!=12

select * from userinfo where sex='False' order by sex asc
select * from userinfo order by id desc
select * from userinfo order by id ,phone

select count(*) as '人数',sex from userinfo group by sex

update userinfo set name='赵柳' where sex='true' and name='zhaoliu'

/×日期处理*/
update t_user_info1 set birth='1919-3-2' where username='yyxinyi'

update t_user_info1 set birth=birth+1 where username='yyxinyi'

update t_user_info1 set birth=getdate() where username='aaa'

select username,datepart("yyyy",birth) as 年,
datepart("mm",birth) as 月,
datepart("dd",birth) as 日,
datepart("hh",birth) as 时,
datepart("mi",birth) as 分,
datepart("ss",birth) as 秒
from t_user_info1

select getdate()+10
select dateadd("mm",10,getdate())

select username,birth,datediff("yyyy",birth,getdate()) from t_user_info1

/×日期处理结束*/

/×删除数据*/

delete from demo1 where column1=3

/×先删除外键表数据，再删除主键表数据*/
delete from demo2
delete from demo1

truncate table demo2

/×删除数据结束*/

/×查询三十到四十之间的数据*/
——solution 1
select top 40 * from userinfo
except select top 30 *from userinfo

——solution 2
select top 10 * from userinfo where id
not in(
select top 30 id from userinfo
)

——solution 3
with t as(select row_number() over(order by id asc) as number,* from userinfo)
select * from t where number between 31 and 40

——solution 4
with t as(select top 40 row_number() over(order by id asc )as noo,* from userinfo)
select id,name,level,upid from t
group by noo ,id,name,level,upid
having noo between 31 and 40

/×select 列 from 表 where 条件 order by 排序 group by 分组 having 再给条件*/

————子查询:将一个查询的结果作为另一个查询的条件
select * from userinfo where id=
(
select id from userinfo where name='%x%'
)
————连接
select t_i_topical.*,t_user_info1.username from t_i_topical
inner join t_user_info1
on t_user_info1.uid=t_i_topical.uid
where username='xinyi'

/×重要系统表*/

if not exists(select * from sysobjects where xtype='U' and name='backup_t_user_info1')
select username,password into backup_t_user_info1 from t_user_info1
else
insert into backup_t_user_info1 select username,password from t_user_info1

/×获取数据库信息*/
select * from master.dbo.sysdatabases

/×获取数据库中对象(表、视图、约束...)信息*/
select * from sysobjects where xtype='U'

/×获取数据库中索引信息*/
select * from sysindexes

/×重要系统表结束*/

——可编程性里->系统函数->字符串函数
select Ascii('ab')——返回字符串表达式中最左边ASCII代码值

select left('123.45678',charindex('.',round(123.45678,2),0)+2)

select left('123.45678',charindex('.','123.45678',0)+2)

select charindex('.','12345678',0)

select left('12323.545',2)

declare @i int
select @i=convert(char(10),1234)
select @i

select max(pwd),min(phone),avg(pwd),count(id),sum(phone) from userinfo

——可编程性里->系统函数->字符串函数

/×集合运算*/

create table temp1
(
t1 int identity(1,1) primary key,
t2 int
)

insert into temp1(t2) values(1)
insert into temp1(t2) values(2)
insert into temp1(t2) values(3)

create table temp2
(
t1 int identity(1,1) primary key,
t3 int
)

insert into temp2(t3) values(1)
insert into temp2(t3) values(2)
insert into temp2(t3) values(11)

select * from temp1
select * from temp2

/×并集，前提是每个数据表中的字段个数都相等*/
select * from temp1
ｕｎｉｏｎ
select * from temp2

/×集合差*/
select * from temp1
except
select * from temp2

select * from temp2
except
select * from temp1

/×交集*/
select * from temp1
intersect
select * from temp2

——in 或者or
select * from userinfo
select * from userinfo where name='张三' or name='李四'

select * from userinfo where name in('张三','李四')

——with
——ok
with t as(select * as t1 from demo2)
delete from t
——error
with t as(select count(*) as t1 from demo2)
delete from t

/×联接*/
select * from userinfo ——:4
select * from score ——:5

——交叉联结(CROSS JOIN) ——:20
select * from userinfo
cross join score

——内联结(INNER JOIN) ——:5
select u.id,u.name,u.pwd,u.sex,u.address,u.phone,u.plity,s.id,s.u_id,s.score from userinfo as u
inner join score as s
on u.id=s.u_id

——左外联结(left outer JOIN) ——:5
select u.id,u.name,u.pwd,u.sex,u.address,u.phone,u.plity,s.id,s.u_id,s.score from userinfo as u
left outer join score as s
on u.id=s.u_id

——右外联结(right outer JOIN) ——:5
select u.id,u.name,u.pwd,u.sex,u.address,u.phone,u.plity,s.id,s.u_id,s.score from userinfo as u
right outer join score as s
on u.id=s.u_id

_ -----------------------与任意单字符匹配

% -----------------------与包含一个或多个字符的字符串匹配

[] ----------------------与特定范围（例如，[a-f]）或特定集（例如，[abcdef]）中的任意单字符匹配。

[^] -----------------------与特定范围（例如，[^a-f]）或特定集（例如，[^abcdef]）之外的任意单字符匹配。

使用like比较字，加上SQL里的通配符，请参考以下：

a、LIKE 'Mc%' 将搜索以字母 Mc 开头的所有字符串（如 McBadden）。

b、LIKE '%inger' 将搜索以字母 inger 结尾的所有字符串（如 Ringer、Stringer）。

c、LIKE '%en%' 将搜索在任何位置包含字母 en 的所有字符串（如 Bennet、Green、McBadden）。

d、LIKE '_heryl' 将搜索以字母 heryl 结尾的所有六个字母的名称（如 Cheryl、Sheryl）。

e、LIKE '[CK]ars[eo]n' 将搜索下列字符串：Carsen、Karsen、Carson 和 Karson（如 Carson）。

f、LIKE '[M-Z]inger' 将搜索以字符串 inger 结尾、以从 M 到 Z 的任何单个字母开头的所有名称（如 Ringer）。

g、LIKE 'M[^c]%' 将搜索以字母 M 开头，并且第二个字母不是 c 的所有名称（如MacFeather）。