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。 1SP)`Q
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一、基础 ?zQ\u{]=
1、说明:创建数据库 c\-5vw||b
CREATE DATABASE database-name syA*!Up
2、说明:删除数据库 CVo@zr$
drop database dbname K\nN2y
3、说明:备份sql server d47b&.v8e
--- 创建 备份数据的 device 5.]+K<:h"A
USE master vJ7I
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' xSs);XO,
--- 开始 备份 "L|Ew#
BACKUP DATABASE pubs TO testBack @T._
4、说明:创建新表 I(#Y\>DG
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Z2(z,pK
根据已有的表创建新表: pB&3JmgR$)
A:create table tab_new like tab_old (使用旧表创建新表) Nlx7"_R"Q
B:create table tab_new as select col1,col2... from tab_old definition only _:Tjq)
5、说明:删除新表 M3o dyO(
drop table tabname BZ">N
6、说明:增加一个列 @R_a'v-
Alter table tabname add column col type 4v33{sp
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 wxkCmrV
7、说明:添加主键: Alter table tabname add primary key(col)
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说明:删除主键: Alter table tabname drop primary key(col) (#BkL:dg
8、说明:创建索引:create [unique] index idxname on tabname(col....) e Pq(:ih
删除索引:drop index idxname :`2<SF^0O
注:索引是不可更改的,想更改必须删除重新建。 2S&e!d-
9、说明:创建视图:create view viewname as select statement m beM/
删除视图:drop view viewname 4{(uw
10、说明:几个简单的基本的sql语句 =zDU!< U
选择:select * from table1 where 范围 @ JZ I
插入:insert into table1(field1,field2) values(value1,value2) ?FVX &{{V
删除:delete from table1 where 范围 Al09R,I;
更新:update table1 set field1=value1 where 范围 C$vKRg\o
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 4[
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排序:select * from table1 order by field1,field2 [desc] {2vk<
总数:select count as totalcount from table1 lTvI;zy
求和:select sum(field1) as sumvalue from table1 6b~Zv$5^Y-
平均:select avg(field1) as avgvalue from table1 ]{{A/ j\
最大:select max(field1) as maxvalue from table1 N#Y%+1
最小:select min(field1) as minvalue from table1 81eDN6
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11、说明:几个高级查询运算词 (8TB*BhQ_
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A: UNION 运算符 o%i^t4J$e
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。 gV$j ]
B: EXCEPT 运算符 -$f~V\M
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。 7*^-3Tt83
C: INTERSECT 运算符 rIH/<@+
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。 'C8VD+p
注:使用运算词的几个查询结果行必须是一致的。 "=@b>d6U+
12、说明:使用外连接 AqB5B5}
A、left outer join: SG_^Rd9
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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。 L{jJDd
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 :tp2@*]9Z
B:right outer join: =@AWw:!:,
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。 mcy\nAf5%
C:full outer join: L3JFQc/oh~
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。 Yz=(zj
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二、提升 gELk u .
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) CL.JalR`b
法一:select * into b from a where 1<>1 K#rfQ0QK/!
法二:select top 0 * into b from a OSQZ5:g|
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Py$Q]s?\1
insert into b(a, b, c) select d,e,f from b; {YC!pDG
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) Ehi)n)HhG"
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 f.JZ[+
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. mE'y$5ZxY
4、说明:子查询(表名1:a 表名2:b) ye:pGa w
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) -G e5gQ=
5、说明:显示文章、提交人和最后回复时间 rZ2X$FO@
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b b6:A-jb*I
6、说明:外连接查询(表名1:a 表名2:b) (+68s9XS7
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c C93BK)$}
7、说明:在线视图查询(表名1:a ) 26PUO$&b.
select * from (SELECT a,b,c FROM a) T where t.a > 1; X1&Ug^
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 )Fx"S.Ok
select * from table1 where time between time1 and time2 9] fhH
select a,b,c, from table1 where a not between 数值1 and 数值2 M(|Qvh{Q6
9、说明:in 的使用方法 v".q578
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select * from table1 where a [not] in ('值1','值2','值4','值6') fft FNHP
10、说明:两张关联表,删除主表中已经在副表中没有的信息 \ZX5dFu0
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) T]-yTsto
11、说明:四表联查问题: eQu%TZ(x-$
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 ..... g}"`@H(9r3
12、说明:日程安排提前五分钟提醒 xI}o8G KQq
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 dU1w)Y
13、说明:一条sql 语句搞定数据库分页 XTEC0s"F
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 I=o[\?u*_
14、说明:前10条记录 to,DN2rN
select top 10 * form table1 where 范围 c[\ :^w^I6
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.) 4YDK`:4I~
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ~XN--4%Q
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 ;*1bTdB5a
(select a from tableA ) except (select a from tableB) except (select a from tableC) uPKq<hBI
17、说明:随机取出10条数据 <_$]!Z6UR
select top 10 * from tablename order by newid() ]E'BFon
18、说明:随机选择记录 XI:8_F;Q
select newid() pd{W(M78g
19、说明:删除重复记录 =F'p#N0_2
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) -1iKeyyA
20、说明:列出数据库里所有的表名 Ec
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select name from sysobjects where type='U' 9pUvw_9MY
21、说明:列出表里的所有的 fZ1v|
select name from syscolumns where id=object_id('TableName') :f%FM&b
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 %E#OUo[y/
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type #<0Yx9Jh.
显示结果: ,Tc3koi
type vender pcs @ODwO;_R5
电脑 A 1 E
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电脑 A 1 f2Zi.?``H
光盘 B 2 28FC@&'H
光盘 A 2 cKuU#&FaV
手机 B 3 kR$>G2$!
手机 C 3 Wt5x*p-!C
23、说明:初始化表table1 0zm)MSg
TRUNCATE TABLE table1
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24、说明:选择从10到15的记录 y6NOHPp@
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ie|I*;#
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三、技巧 !`=ms1%U
1、1=1,1=2的使用,在SQL语句组合时用的较多 +13h*
"where 1=1" 是表示选择全部 "where 1=2"全部不选, wI.i\S
如: Vcn04j#Q
if @strWhere !='' Vij P;
begin f0p+l-iEv
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ^2f'I iE
end 7jvy]5y8&~
else 8 2qf7`
begin NbOeF7cq+
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' j1_ E^
end j,%@%upM
我们可以直接写成 xw_VK1
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere vzV,}
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2、收缩数据库 n][/c_]q
--重建索引 3ThBy'
DBCC REINDEX 06DT2
DBCC INDEXDEFRAG }
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--收缩数据和日志 5v"r>q[
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DBCC SHRINKDB uD4=1g6[s
DBCC SHRINKFILE !`5[(lm
3、压缩数据库 pRI<L'
dbcc shrinkdatabase(dbname) @P=St\;VP
4、转移数据库给新用户以已存在用户权限 OS8 ^mC
exec sp_change_users_login 'update_one','newname','oldname' I)#=#eI*:
go iEx.BQ+
5、检查备份集 &:}e`u@5|
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' L9tjHC]
6、修复数据库 }OY]mAv-B
ALTER DATABASE [dvbbs] SET SINGLE_USER H.-jBFt}
GO ~RcI+jR)
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK @X`~r8&
GO b3(pRg[Fp
ALTER DATABASE [dvbbs] SET MULTI_USER C!Cg.^;
GO 9~+A<X]Hd
7、日志清除 7sP;+G
SET NOCOUNT ON n]M1'yU
DECLARE @LogicalFileName sysname, \b{Aj,6,
@MaxMinutes INT, u I$|M
@NewSize INT \zj _6Os
USE tablename -- 要操作的数据库名 s_]p6M
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 $=dp)
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 2|'v[
@NewSize = 1 -- 你想设定的日志文件的大小(M) a*LT <N
-- Setup / initialize (vte8uQe
DECLARE @OriginalSize int l;i,V;@t
SELECT @OriginalSize = size !0ly1T 9
FROM sysfiles Y.I-hl1<r
WHERE name = @LogicalFileName 9pPb]v,6
SELECT 'Original Size of ' + db_name() + ' LOG is ' + p- 5)J&
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + {\-rZb==F2
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' O%)@> 5#S
FROM sysfiles RjS;Ck@;
WHERE name = @LogicalFileName )"?6Es SF
CREATE TABLE DummyTrans fDc>E+,
(DummyColumn char (8000) not null) [8*Ovd
DECLARE @Counter INT, '\%c"?
@StartTime DATETIME, V:F;Nq%+j
@TruncLog VARCHAR(255) w0QN5?
SELECT @StartTime = GETDATE(), Xx{ho4qq
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' wX}N===
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ;\`~M
EXEC (@TruncLog) 8
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-- Wrap the log if necessary. gfQ&U@N
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired "zW3dKVc
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) =4GJYhj
AND (@OriginalSize * 8 /1024) > @NewSize (]wi^dE
BEGIN -- Outer loop. }.Eq_wP<
SELECT @Counter = 0 3L/qU^`
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) =ark?<E
BEGIN -- update %M8Egr2|0
INSERT DummyTrans VALUES ('Fill Log') a%*l]S0z"
DELETE DummyTrans R'a%_sACj>
SELECT @Counter = @Counter + 1 wu?ahNb.`Y
END AH`n
EXEC (@TruncLog) i^P@?
END ZJ(/cD
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 97:1L4w.(
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + * d6[kY
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' xGbr>OqkTX
FROM sysfiles "%~\kJ(G
WHERE name = @LogicalFileName v +-f
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DROP TABLE DummyTrans ps0wN%tA
SET NOCOUNT OFF f`<j(.{9F
8、说明:更改某个表 ]2G5ng' @
exec sp_changeobjectowner 'tablename','dbo' <%eY>E
9、存储更改全部表 `B+%W
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch w?CbATQ
@OldOwner as NVARCHAR(128), 0P`wh=")
@NewOwner as NVARCHAR(128) `mPmEV<
AS f@l 6]z{.L
DECLARE @Name as NVARCHAR(128) ~ZU;0#
DECLARE @Owner as NVARCHAR(128) kTQ:k
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DECLARE @OwnerName as NVARCHAR(128) A7U'>r_.
DECLARE curObject CURSOR FOR CG'NC\x5
select 'Name' = name, &{QB}r
'Owner' = user_name(uid) &SS"A*xg
from sysobjects ToNi<~
where user_name(uid)=@OldOwner 8?] :>
order by name
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OPEN curObject ~^/zCPy[w
FETCH NEXT FROM curObject INTO @Name, @Owner J5L P#o(V
WHILE(@@FETCH_STATUS=0) $mm =$.
BEGIN WujIaJt-
if @Owner=@OldOwner }_XW?^/8
begin (^GVy=
set @OwnerName = @OldOwner + '.' + rtrim(@Name) Myss$gt}
exec sp_changeobjectowner @OwnerName, @NewOwner khT&[!J{>
end ,CW]d#P|
-- select @name,@NewOwner,@OldOwner &_FNDJ>MCk
FETCH NEXT FROM curObject INTO @Name, @Owner `;fh<kv
END PK1j$&F
close curObject BmYU#h
deallocate curObject k*|dX.C:
GO gd<8RVA
10、SQL SERVER中直接循环写入数据 oTZ?x}Z1
declare @i int "?,3O2t
set @i=1 FD(zj ^*
while @i<30 6QdNGpN
begin O%v(~&OSl
insert into test (userid) values(@i) ^)N[x''a
set @i=@i+1 nPq\J~M
end ~\dpD
小记存储过程中经常用到的本周,本月,本年函数 >_M}l@1
Dateadd(wk,datediff(wk,0,getdate()),-1) >V(>2eD'S
Dateadd(wk,datediff(wk,0,getdate()),6) .jMm-vox}
Dateadd(mm,datediff(mm,0,getdate()),0) mFayU w
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ]i*q*]x2u
Dateadd(yy,datediff(yy,0,getdate()),0) FW7+!A&F
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) OXDlwbwL
上面的SQL代码只是一个时间段 ))c;DJc
Dateadd(wk,datediff(wk,0,getdate()),-1) lp[3z&u
Dateadd(wk,datediff(wk,0,getdate()),6) ub6\m=Y7
就是表示本周时间段. ($(6]?J(?7
下面的SQL的条件部分,就是查询时间段在本周范围内的: ?97MW a
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) DGY#pnCu
而在存储过程中 yb/<
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select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) W9 y8dw.
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Orh5d7+S