SQL语句先前写的时候,很容易把一些特殊的用法忘记,我特此整理了一下SQL语句操作。 ZB+N[VJs)
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一、基础 mSw$?
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1、说明:创建数据库 (&25 8i,
CREATE DATABASE database-name }b//oe7
2、说明:删除数据库 Cr!}qZq
drop database dbname (QO8_
3、说明:备份sql server g UfLw
--- 创建 备份数据的 device nLA8Hy"8z
USE master `
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' h";0i:
--- 开始 备份 h
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BACKUP DATABASE pubs TO testBack n9Mi?#xIp
4、说明:创建新表 .|[5*-
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) e|`QW|9 .
根据已有的表创建新表: &\3k(j
A:create table tab_new like tab_old (使用旧表创建新表) x*8lz\w
B:create table tab_new as select col1,col2... from tab_old definition only B74L/h
5、说明:删除新表 c$cb2V7,
drop table tabname c.-/e u^|
6、说明:增加一个列 B.wRZDEvc
Alter table tabname add column col type _QD##`<
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 YLr<^G-v
7、说明:添加主键: Alter table tabname add primary key(col) aV^wTs#2I
说明:删除主键: Alter table tabname drop primary key(col) 8Z=d+}Gg<
8、说明:创建索引:create [unique] index idxname on tabname(col....) //SH=>w2
删除索引:drop index idxname ]h(}%fk_
注:索引是不可更改的,想更改必须删除重新建。 T-0[P;
9、说明:创建视图:create view viewname as select statement g4NxNjM;
删除视图:drop view viewname $ekB+
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10、说明:几个简单的基本的sql语句 Lo'P;Sb4<}
选择:select * from table1 where 范围 =}:9y6QR.
插入:insert into table1(field1,field2) values(value1,value2) Y9b|lP7!
删除:delete from table1 where 范围 ZnX]Q+w
更新:update table1 set field1=value1 where 范围 *W'F6Hpu
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! a3&&7n
排序:select * from table1 order by field1,field2 [desc] Q(P'4XCm
总数:select count as totalcount from table1 q/
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求和:select sum(field1) as sumvalue from table1 6x1!!X+)+
平均:select avg(field1) as avgvalue from table1 .qjVw?E
最大:select max(field1) as maxvalue from table1 }y<p_dZI
最小:select min(field1) as minvalue from table1 yPgDb[V+
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11、说明:几个高级查询运算词 iKy_DV;J
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A: UNION 运算符 N5 BC<pu
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。 K~j&Q{yws@
B: EXCEPT 运算符
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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。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 0KW@j>=jK
C: INTERSECT 运算符 zJp}JO
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。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 R)>/P{A-P
注:使用运算词的几个查询结果行必须是一致的。 QZcdfJck=+
12、说明:使用外连接 GpjyF_L
A、left outer join: '@Zau\xC
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。 B8+J0jdg6%
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 q Ee1OB
B:right outer join: ()< E?D=
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。 RC_w 1:h
C:full outer join: OYw~I.Rq
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。 4!'1o`8vs
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二、提升 zEG6T *
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) `>M-J-J
法一:select * into b from a where 1<>1 R{s&6
法二:select top 0 * into b from a "62vwWrwO
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) (=v :@\r
insert into b(a, b, c) select d,e,f from b; AlW0GK=N-p
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) V SJGp`
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 tb^8jC
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Nm{\?
4、说明:子查询(表名1:a 表名2:b) sFqLxSo_I
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) ff.(X!
5、说明:显示文章、提交人和最后回复时间 T#;W5<"
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b #) eI]
6、说明:外连接查询(表名1:a 表名2:b) 8]@)0q {r
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c k
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7、说明:在线视图查询(表名1:a ) ` ZO#n
select * from (SELECT a,b,c FROM a) T where t.a > 1; Z(fXN$
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 ^[K3]*!@
select * from table1 where time between time1 and time2 r-M:YB
select a,b,c, from table1 where a not between 数值1 and 数值2
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9、说明:in 的使用方法 k)Y}X)\36
select * from table1 where a [not] in ('值1','值2','值4','值6') ^
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10、说明:两张关联表,删除主表中已经在副表中没有的信息 i$~2pr
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) N=1zhI:VaQ
11、说明:四表联查问题: 'H"wu
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select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... P5u
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12、说明:日程安排提前五分钟提醒 dGxk
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 r)ni;aP
13、说明:一条sql 语句搞定数据库分页 bSOxM/N
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 2TH13k$
14、说明:前10条记录 >FO4]
select top 10 * form table1 where 范围 ==zt)s.G(+
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) =oN(1k^
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 2K^D%U
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 ,EkzBVgo
(select a from tableA ) except (select a from tableB) except (select a from tableC) W[pOLc-
17、说明:随机取出10条数据 5a$Q}!6E.Y
select top 10 * from tablename order by newid() X9W'.s.[Q
18、说明:随机选择记录 gZa/?[+
select newid() ~7!=<MW
19、说明:删除重复记录 \!!qzrq
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) QucDIZ
20、说明:列出数据库里所有的表名 |Z]KF>S]
select name from sysobjects where type='U' L-B"P&
21、说明:列出表里的所有的 xvP=i/SO
select name from syscolumns where id=object_id('TableName')
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22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 "Di27Rq
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type :O`7kZ]=n
显示结果: ~d0:>8zQR
type vender pcs OT1
电脑 A 1 @ |bN[X L
电脑 A 1 l@;UwnI
光盘 B 2 #[|~m;K(w
光盘 A 2 4@2<dw|*h
手机 B 3 )-98pp7~BB
手机 C 3 `Aa}q(}k
23、说明:初始化表table1 7_OC&hhL
TRUNCATE TABLE table1 U
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24、说明:选择从10到15的记录 `pMI@"m
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc h |Ofi
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三、技巧 j@N z
1、1=1,1=2的使用,在SQL语句组合时用的较多 CSKOtqKQ)
"where 1=1" 是表示选择全部 "where 1=2"全部不选, C`G+b{o
如: fL0dy[Ch@
if @strWhere !='' 9((BOq
begin [/h3HyZ.
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 9v\x&h
end kJQH{n+)R
else i D6f/|g
begin -L4fp
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' (`W_ -PI
end 7a$K@iWU
我们可以直接写成 vbt0 G-%Z
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere <x QvS^|[
2、收缩数据库 zKh^BwhO|X
--重建索引 o,-p[1b
DBCC REINDEX qPI\Y3ZU
DBCC INDEXDEFRAG s9[?{}gd
--收缩数据和日志 |j 9d.M
DBCC SHRINKDB ~]sj.>P
DBCC SHRINKFILE nt 9LBea
3、压缩数据库 zd%n)jlwR
dbcc shrinkdatabase(dbname) Lud[.>i
4、转移数据库给新用户以已存在用户权限 f ZEyXb
exec sp_change_users_login 'update_one','newname','oldname' A-n@:` n~
go 7+N0$0w%r
5、检查备份集 lu_kir~
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' gxKL
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6、修复数据库 ;mT|0&o>#
ALTER DATABASE [dvbbs] SET SINGLE_USER
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GO 'E\/H17
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK .Us)YVbk
GO HZINsIm!?
ALTER DATABASE [dvbbs] SET MULTI_USER {l
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GO 0W_olnZ
7、日志清除 q8m{zSr
SET NOCOUNT ON WGmXq.
DECLARE @LogicalFileName sysname, (vR9vOpJ
@MaxMinutes INT, r\PO?1
@NewSize INT )WBp.j /#
USE tablename -- 要操作的数据库名 c)*,">$#
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ojc m%yd
@MaxMinutes = 10, -- Limit on time allowed to wrap log. g~7x+cu0
@NewSize = 1 -- 你想设定的日志文件的大小(M) Arr(rM
-- Setup / initialize ?|i
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DECLARE @OriginalSize int qjBF]3%t%
SELECT @OriginalSize = size ?l> <?i
FROM sysfiles Vn=K5nm
WHERE name = @LogicalFileName ?[Sac]h
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + !_?K(X~/
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 1Yk!R9.
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' {"dvU"y)\
FROM sysfiles B*OEG*t
WHERE name = @LogicalFileName >='y+68
CREATE TABLE DummyTrans >z'T"R/
(DummyColumn char (8000) not null) [Qw BSq8)
DECLARE @Counter INT, gLDO|ADni
@StartTime DATETIME, q`Rc \aWB%
@TruncLog VARCHAR(255) .](~dVp%~
SELECT @StartTime = GETDATE(), @u>:(9bp
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' gzMp&J
DBCC SHRINKFILE (@LogicalFileName, @NewSize) U/#X,Bi~
EXEC (@TruncLog) wsKOafrV
-- Wrap the log if necessary. 7Dt*++:
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ^)nIf)9}7
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) *'-[J 2
AND (@OriginalSize * 8 /1024) > @NewSize We`6# \Z X
BEGIN -- Outer loop. YigDrW
SELECT @Counter = 0 E%b*MU
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Y9}ga4
BEGIN -- update $~ >/_<~
INSERT DummyTrans VALUES ('Fill Log') 9#>t% IF~
DELETE DummyTrans MaS-*;BY,
SELECT @Counter = @Counter + 1 (y^svXU}a
END SG4)kQ
EXEC (@TruncLog) ^XgBkC~
END gcA,u)z}R
SELECT 'Final Size of ' + db_name() + ' LOG is ' + "d; T1
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 9Ai3p
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' CcJ%;.V,T
FROM sysfiles r`\6+ Ntb.
WHERE name = @LogicalFileName d)WGI
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DROP TABLE DummyTrans D7lRZb
SET NOCOUNT OFF F"^/R
8、说明:更改某个表 O>@ChQF
exec sp_changeobjectowner 'tablename','dbo' TFZxk
9、存储更改全部表 "$I8EW/1
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch FyhLMW3
@OldOwner as NVARCHAR(128), O<`N0
@NewOwner as NVARCHAR(128) 5M&<tj/[a0
AS 6no&2a|D
DECLARE @Name as NVARCHAR(128) ~LF/wx>
DECLARE @Owner as NVARCHAR(128) HkQ rij6
DECLARE @OwnerName as NVARCHAR(128) LOEiV
DECLARE curObject CURSOR FOR >^~W'etX|
select 'Name' = name, 9 gc0Ri[4m
'Owner' = user_name(uid) 3P *[!KI
from sysobjects [9C{\t
where user_name(uid)=@OldOwner v.6K;TY.
order by name 8U)*kmq
OPEN curObject rqWD#FB=z
FETCH NEXT FROM curObject INTO @Name, @Owner e9;5.m
WHILE(@@FETCH_STATUS=0) >c@jl
BEGIN Tr.u'b(
if @Owner=@OldOwner mhgvN-? "h
begin M,vCAZ
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ZK4d;oa",
exec sp_changeobjectowner @OwnerName, @NewOwner P_.zp5>
end o_sb+Vn|
-- select @name,@NewOwner,@OldOwner $/kZKoF{f
FETCH NEXT FROM curObject INTO @Name, @Owner Tg@:mw5
END xyrlR;Sk
close curObject cz41<SFL
deallocate curObject MMy\u) 4
GO -KL5sK
10、SQL SERVER中直接循环写入数据 IMSLHwZ
declare @i int T0X+\&W
set @i=1 Oj>;[O"
while @i<30 em9nuXG
begin @M*oq2U;
insert into test (userid) values(@i) $EnBigb!
set @i=@i+1 AQGl}%k_
end XI>HC'.0
小记存储过程中经常用到的本周,本月,本年函数 ':7gYP*v
Dateadd(wk,datediff(wk,0,getdate()),-1) Y~B-dx'V
Dateadd(wk,datediff(wk,0,getdate()),6) d$HPpi1LL
Dateadd(mm,datediff(mm,0,getdate()),0) r]deVd G
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) l@ 5kw]6
Dateadd(yy,datediff(yy,0,getdate()),0) T2}X~A
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) =<X4LO)C
上面的SQL代码只是一个时间段 XC!Y {lp
Dateadd(wk,datediff(wk,0,getdate()),-1) f_z]kA
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Dateadd(wk,datediff(wk,0,getdate()),6) T2_b5j3i
就是表示本周时间段. Y;{(?0
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下面的SQL的条件部分,就是查询时间段在本周范围内的: Ce:w^P+
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) $#-O^0D
而在存储过程中 @6Z6@Pq(xQ
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) b"y4-KV
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) .naSK`J,`