SQLServer基础语法实例应用（一）
一、基础1、说明：创建数据库 ? 1 CREATE DATABASE database-name 2、说明：删除数据库 ? 1 DROP DATABASE database-name 3、说明：备份数据库 ? 1 2 3 4 5 USE master -- 创建 备份数据的 device EXEC sp_addumpdevice 'disk', 'cc_jz', 'd:cc_jz.dat' --
一、基础 1、说明：创建数据库
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CREATE DATABASE database-name
2、说明：删除数据库
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DROP DATABASE database-name
3、说明：备份数据库
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USE master
-- 创建 备份数据的 device
EXEC sp_addumpdevice 'disk', 'cc_jz', 'd:cc_jz.dat'
-- 开始 备份
BACKUP DATABASE cc_jz TO cc_jz
4、说明：创建新表
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..)
--> 测试数据：[a]
if object_id('[a]') is not null drop table [a]
go
create table [a]([ID] int,[品名] varchar(6),[入库数量] int,[入库时间] datetime)
insert [a]
select 1,'矿泉水',100,'2013-01-02' union all
select 2,'方便面',60,'2013-01-03' union all
select 3,'方便面',50,'2013-01-03' union all
select 4,'矿泉水',80,'2013-01-04' union all
select 5,'方便面',50,'2013-01-05'
select * from a
/*
ID 品名 入库数量 入库时间
----------- ------ ----------- -----------------------
1 矿泉水 100 2013-01-02 00:00:00.000
2 方便面 60 2013-01-03 00:00:00.000
3 方便面 50 2013-01-03 00:00:00.000
4 矿泉水 80 2013-01-04 00:00:00.000
5 方便面 50 2013-01-05 00:00:00.000
(5 行受影响)
*/
5、说明：删除新表
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drop table tabname
6、说明：增加一个列
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Alter table tabname add column col type
Alter table a add col int
select * from a
/*
ID 品名 入库数量 入库时间 col
----------- ------ ----------- ----------------------- -----------
1 矿泉水 100 2013-01-02 00:00:00.000 NULL
2 方便面 60 2013-01-03 00:00:00.000 NULL
3 方便面 50 2013-01-03 00:00:00.000 NULL
4 矿泉水 80 2013-01-04 00:00:00.000 NULL
5 方便面 50 2013-01-05 00:00:00.000 NULL
(5 行受影响)
*/
7、说明：添加主键：
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Alter table tabname add primary key(col)
说明：删除主键：
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Alter table tabname drop primary key(col)
8、说明：创建索引：
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create [unique] index idxname on tabname(col….)
删除索引：
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drop index idxname
注：索引是不可更改的，想更改必须删除重新建。
9、说明：创建视图：
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create view viewname as select statement
删除视图：
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drop view viewname
10、说明：几个简单的基本的sql语句
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--选择：
select * from table1
--插入：
insert into table1(field1,field2) values(value1,value2)
--删除：
delete from table1 --where 范围
--更新：
update table1 set field1=value1 --where 范围
--查找：
select * from table1 where field1 like '%value1%'
--排序：
select * from table1 order by field1,field2 [desc]
--总数：
select count as totalcount from table1
--求和：
select sum(field1) as sumvalue from table1
--平均：
select avg(field1) as avgvalue from table1
--最大：
select max(field1) as maxvalue from table1
--最小：
select min(field1) as minvalue from table1
11、说明：几个高级查询运算词
A： UNION/UNION ALL 运算符UNION 运算符通过组合其他两个结果表（例如 TABLE1 和 TABLE2）并消去表中任何重复行而派生出一个结果表。
当 ALL 随 UNION 一起使用时（即 UNION ALL），不消除重复行。两种情况下，派生表的每一行不是来自 TABLE1 就是来自 TABLE2。
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--> 测试数据：[a]
if object_id('[a]') is not null drop table [a]
go
create table [a]([ID] int)
insert [a]
select 1 union all
select 1 union all
select 2 union all
select 3 union all
select null
select * from a
/*
(5 行受影响)
ID
-----------
1
1
2
3
NULL
(5 行受影响)
*/
--> 测试数据：[b]
if object_id('[b]') is not null drop table [b]
go
create table [b]([ID] int)
insert [b]
select 1 union all
select 2 union all
select 2 union all
select 4 union all
select null
select * from b
/*
(5 行受影响)
ID
-----------
1
2
2
4
NULL
(5 行受影响)
*/
--合并去重
select * from a
union
select * from b
/*
ID
-----------
NULL
1
2
3
4
(5 行受影响)
*/
--合并不去重
select * from a
union all
select * from b
/*
ID
-----------
1
1
2
3
NULL
1
2
2
4
NULL
(10 行受影响)
*/
B： EXCEPT 运算符EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。
注意：根本没有EXCEPT ALL 的用法；网上很多文章里写有EXCEPT ALL ，实际上是错误的。（测试SQL Server 2000 2005 2008R2 2012都不好用）
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--> 测试数据：[a]
if object_id('[a]') is not null drop table [a]
go
create table [a]([ID] int)
insert [a]
select 1 union all
select 1 union all
select 2 union all
select 3 union all
select null
select * from a
/*
(5 行受影响)
ID
-----------
1
1
2
3
NULL
(5 行受影响)
*/
--> 测试数据：[b]
if object_id('[b]') is not null drop table [b]
go
create table [b]([ID] int)
insert [b]
select 1 union all
select 2 union all
select 2 union all
select 4 union all
select null
select * from b
/*
(5 行受影响)
ID
-----------
1
2
2
4
NULL
(5 行受影响)
*/
--取两表不同数据并去重
select * from a
EXCEPT
select * from b
/*
ID
-----------
3
(1 行受影响)
*/
C： INTERSECT 运算符INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。
注意：根本没有INTERSECT ALL 的用法；网上很多文章里写有INTERSECT ALL ，实际上是错误的。（测试SQL Server 2000 2005 2008R2 2012都不好用）
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--> 测试数据：[a]
if object_id('[a]') is not null drop table [a]
go
create table [a]([ID] int)
insert [a]
select 1 union all
select 1 union all
select 2 union all
select 3 union all
select null
select * from a
/*
(5 行受影响)
ID
-----------
1
1
2
3
NULL
(5 行受影响)
*/
--> 测试数据：[b]
if object_id('[b]') is not null drop table [b]
go
create table [b]([ID] int)
insert [b]
select 1 union all
select 2 union all
select 2 union all
select 4 union all
select null
select * from b
/*
(5 行受影响)
ID
-----------
1
2
2
4
NULL
(5 行受影响)
*/
--取两表相同数据并去重
select * from a
INTERSECT
select * from b
/*
ID
-----------
NULL
1
2
(3 行受影响)
*/
12、说明：使用外连接A、left （outer） join：
左外连接（左连接）：结果集几包括连接表的匹配行，也包括左连接表的所有行。
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c
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--> 测试数据：[a]
if object_id('[a]') is not null drop table [a]
go
create table [a]([ID] int)
insert [a]
select 1 union all
select 1 union all
select 2 union all
select 3 union all
select null
select * from a
/*
(5 行受影响)
ID
-----------
1
1
2
3
NULL
(5 行受影响)
*/
--> 测试数据：[b]
if object_id('[b]') is not null drop table [b]
go
create table [b]([ID] int)
insert [b]
select 1 union all
select 2 union all
select 2 union all
select 4 union all
select null
select * from b
/*
(5 行受影响)
ID
-----------
1
2
2
4
NULL
(5 行受影响)
*/
select a.*,b.* from a a LEFT JOIN b b ON a.id= b.id
/*
ID ID
----------- -----------
1 1
1 1
2 2
2 2
3 NULL
NULL NULL
(6 行受影响)
*/
B：right （outer） join:右外连接(右连接)：结果集既包括连接表的匹配连接行，也包括右连接表的所有行。
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--> 测试数据：[a]
if object_id('[a]') is not null drop table [a]
go
create table [a]([ID] int)
insert [a]
select 1 union all
select 1 union all
select 2 union all
select 3 union all
select null
select * from a
/*
(5 行受影响)
ID
-----------
1
1
2
3
NULL
(5 行受影响)
*/
--> 测试数据：[b]
if object_id('[b]') is not null drop table [b]
go
create table [b]([ID] int)
insert [b]
select 1 union all
select 2 union all
select 2 union all
select 4 union all
select null
select * from b
/*
(5 行受影响)
ID
-----------
1
2
2
4
NULL
(5 行受影响)
*/
select a.*,b.* from a a RIGHT JOIN b b ON a.id= b.id
/*
ID ID
----------- -----------
1 1
1 1
2 2
2 2
NULL 4
NULL NULL
(6 行受影响)
*/
C：full/cross （outer） join：全外连接：不仅包括符号连接表的匹配行，还包括两个连接表中的所有记录。
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--> 测试数据：[a]
if object_id('[a]') is not null drop table [a]
go
create table [a]([ID] int)
insert [a]
select 1 union all
select 1 union all
select 2 union all
select 3 union all
select null
select * from a
/*
(5 行受影响)
ID
-----------
1
1
2
3
NULL
(5 行受影响)
*/
--> 测试数据：[b]
if object_id('[b]') is not null drop table [b]
go
create table [b]([ID] int)
insert [b]
select 1 union all
select 2 union all
select 2 union all
select 4 union all
select null
select * from b
/*
(5 行受影响)
ID
-----------
1
2
2
4
NULL
(5 行受影响)
*/
select a.*,b.* from a a FULL JOIN b b ON a.id= b.id
/*
ID ID
----------- -----------
1 1
1 1
2 2
2 2
3 NULL
NULL NULL
NULL 4
NULL NULL
(8 行受影响)
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