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。 S/A1RUt
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一、基础 wTq{ sW&
1、说明:创建数据库 2a=sm1?
CREATE DATABASE database-name T2'RATfG
2、说明:删除数据库 C"uahP[Y
drop database dbname B|=|.qp$)
3、说明:备份sql server v({N:ya
--- 创建 备份数据的 device cD}Sf>
USE master XVVD 0^ Q
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' S7iDTG_@t
--- 开始 备份 f>9s!Hpu_
BACKUP DATABASE pubs TO testBack Ww3wsy x
4、说明:创建新表 X$?3U!
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) s<QkDERMX
根据已有的表创建新表: w|Cx>8P8@
A:create table tab_new like tab_old (使用旧表创建新表) T/r#H__`
B:create table tab_new as select col1,col2... from tab_old definition only Qt>>$3]!!
5、说明:删除新表 Bn?V9TEoO
drop table tabname Gctsp2ndW
6、说明:增加一个列 B}?IEpYp
Alter table tabname add column col type L{{CAB!
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 i&Fiq&V)[
7、说明:添加主键: Alter table tabname add primary key(col) !vD{Df>
说明:删除主键: Alter table tabname drop primary key(col) =<z.mzqu5
8、说明:创建索引:create [unique] index idxname on tabname(col....) '\q f^?9
删除索引:drop index idxname d'
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注:索引是不可更改的,想更改必须删除重新建。 wEW4gz{s
9、说明:创建视图:create view viewname as select statement A
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删除视图:drop view viewname t~7V{ xk
10、说明:几个简单的基本的sql语句 0ZpFE&
选择:select * from table1 where 范围 C#pZw[
插入:insert into table1(field1,field2) values(value1,value2) /'.=sH
删除:delete from table1 where 范围 cgu~
更新:update table1 set field1=value1 where 范围 tiPa6tQ
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! arK_oh0B
排序:select * from table1 order by field1,field2 [desc] ow'Vz
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总数:select count as totalcount from table1 ,3i,P(?(
求和:select sum(field1) as sumvalue from table1 :aLT0q!K
平均:select avg(field1) as avgvalue from table1 ~p0c3*
最大:select max(field1) as maxvalue from table1 B@YyQ'
最小:select min(field1) as minvalue from table1 nz.{P@[Qk
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11、说明:几个高级查询运算词 IeX^4rc(
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A: UNION 运算符 Joe_PS
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 -Ng'<7
B: EXCEPT 运算符 lK'Rn~
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 t>)45<PEw
C: INTERSECT 运算符 Q;Wj?8}
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 r,P1^ uHx
注:使用运算词的几个查询结果行必须是一致的。 =SOe}!
12、说明:使用外连接 YZ$ZcfXDW
A、left outer join: =QJRMF
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。 <+#oBN
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 rX7QbAB
B:right outer join: ppIbjt6r
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。 X .F^$
C:full outer join: AwUi+|7r])
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。 |WryBzZ>on
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二、提升 s^OO^%b
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) -m=
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法一:select * into b from a where 1<>1 iTh:N2/-vc
法二:select top 0 * into b from a p}b/XnV$~
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) KfCoe[Vv
insert into b(a, b, c) select d,e,f from b; I:V0Xxz5t
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) 8x{B~_~
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 q*![AzFh
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. nfW&1a
4、说明:子查询(表名1:a 表名2:b) X;F?:Iw \
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) H y"x
5、说明:显示文章、提交人和最后回复时间 jeyLL<
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Z4$cyL'$P
6、说明:外连接查询(表名1:a 表名2:b) RC|!+TD
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c C${S^v
7、说明:在线视图查询(表名1:a ) =$8nUX`
select * from (SELECT a,b,c FROM a) T where t.a > 1; I]"96'|N
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 Lj\/Ji_
select * from table1 where time between time1 and time2 Hd7,ZHj3^
select a,b,c, from table1 where a not between 数值1 and 数值2 t%zpNd2lk
9、说明:in 的使用方法 lDC$F N
select * from table1 where a [not] in ('值1','值2','值4','值6') WnUweSdW
10、说明:两张关联表,删除主表中已经在副表中没有的信息 @pI5lh
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) !|q<E0@w\
11、说明:四表联查问题: +bK.NcS
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 ..... iGDLZE+?
12、说明:日程安排提前五分钟提醒 %u^JpC{E
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 }u+a<:pkK
13、说明:一条sql 语句搞定数据库分页 UmnE@H"t$\
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 a9zw)A
14、说明:前10条记录 ]u-]'P
select top 10 * form table1 where 范围 /<CSVJ_r
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) WD;Y~|
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) }),w1/#5u8
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 DcIvhB p
(select a from tableA ) except (select a from tableB) except (select a from tableC) =z?%;4'|
17、说明:随机取出10条数据 i`/+,<
select top 10 * from tablename order by newid() D47R
18、说明:随机选择记录 m|=Ecu
select newid() y~
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19、说明:删除重复记录 z|?R/Gf8
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) !/ y!QXj
20、说明:列出数据库里所有的表名 )5%C3/Dl!
select name from sysobjects where type='U' q'oMAM f}
21、说明:列出表里的所有的 lT\a2.E
select name from syscolumns where id=object_id('TableName') j7FN\
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22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 Mfk2mIy
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type d0hhMx6$
显示结果: zJ+8FWy:S
type vender pcs k{tMzx]F__
电脑 A 1 NVIK>cT6
电脑 A 1 <?D[9Mk$
光盘 B 2 EA.D}X C
光盘 A 2 AeIrr*~]B
手机 B 3 Cp^@zw*/
手机 C 3 E^_wI>
23、说明:初始化表table1 'B83m#HR#
TRUNCATE TABLE table1 c/L>>t
24、说明:选择从10到15的记录 53HU.
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc I"AYWo?
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三、技巧 %xwIt~Y
1、1=1,1=2的使用,在SQL语句组合时用的较多 z|G9,:9
"where 1=1" 是表示选择全部 "where 1=2"全部不选, nfb]VN~(
如: 9[v1h,L
if @strWhere !='' -Z4{;I[Q@
begin 0Q"u#V Sp
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere QQk{\PV
end :H.
else * v8Ts
begin |5I'CNi\
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' %zC[KE*~
end PIA)d-Z
我们可以直接写成 d;tkJ2@NO
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere qP!eJ6[Nh"
2、收缩数据库 3`hUo5K
--重建索引 })vOaYT|-
DBCC REINDEX QYXx:nIrg
DBCC INDEXDEFRAG 8pM>Co!
--收缩数据和日志 3<|`0pt}
DBCC SHRINKDB <0|9Tn2O
DBCC SHRINKFILE _|<d5TI
3、压缩数据库 k.h`Cji@
dbcc shrinkdatabase(dbname) Ap&)6g
4、转移数据库给新用户以已存在用户权限 (-7ZI"Ku
exec sp_change_users_login 'update_one','newname','oldname' SEQ%'E5-'
go l>lW]W
5、检查备份集 +y[@T6_
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' )/4(e?%=
6、修复数据库 3zuF{Q2P<
ALTER DATABASE [dvbbs] SET SINGLE_USER ~:;3uLs,8
GO \^+ILYO:$
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK <j}lp-
GO !=Y;h[J.p
ALTER DATABASE [dvbbs] SET MULTI_USER M"=n>;*X
GO 9D@$i<D:
7、日志清除 %kf>&b,Mi
SET NOCOUNT ON
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DECLARE @LogicalFileName sysname, fbrp#G71y
@MaxMinutes INT, W:&R~R
@NewSize INT UIJx*
USE tablename -- 要操作的数据库名 /rB{[zk
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 u%|zc=
@MaxMinutes = 10, -- Limit on time allowed to wrap log. <Pqv;WI|R
@NewSize = 1 -- 你想设定的日志文件的大小(M) |wxGpBau
-- Setup / initialize lYf+V8{
DECLARE @OriginalSize int :L?_Y/K
SELECT @OriginalSize = size :@
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FROM sysfiles L/}iy}
WHERE name = @LogicalFileName @`u?bnx]e
SELECT 'Original Size of ' + db_name() + ' LOG is ' + F
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + UyYfpL"$A"
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' \L!uHAE2a
FROM sysfiles L6:h.1 U$
WHERE name = @LogicalFileName -=$2p0"R
CREATE TABLE DummyTrans yFIy`9R
(DummyColumn char (8000) not null) 8"'x)y
DECLARE @Counter INT, -Q
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@StartTime DATETIME, ?dy~mob
@TruncLog VARCHAR(255) rp!
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SELECT @StartTime = GETDATE(), ,#u\l>&$
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' $j`
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) uq7T{7~<
EXEC (@TruncLog) +}7fg82)
-- Wrap the log if necessary. IY(h~O
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired _]#klL
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) }F1s
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AND (@OriginalSize * 8 /1024) > @NewSize =6 %|?5G
BEGIN -- Outer loop. oVkq2
SELECT @Counter = 0 :{g7lTM
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) X33v:9=
BEGIN -- update Z_z#QX>=D
INSERT DummyTrans VALUES ('Fill Log') .CV _\
DELETE DummyTrans -/{af
SELECT @Counter = @Counter + 1 60B-ay0e$b
END $%qg"
EXEC (@TruncLog) W^g'}}]T
END <bmLy_":
SELECT 'Final Size of ' + db_name() + ' LOG is ' + GG-[`!>.pw
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + n[k1np$7?6
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' T-L5zu
FROM sysfiles 2hOPzv&B
WHERE name = @LogicalFileName (i`(>I.(/
DROP TABLE DummyTrans CmC0k-%w
SET NOCOUNT OFF q(]f]Vl|0
8、说明:更改某个表 \ElX~$fS
exec sp_changeobjectowner 'tablename','dbo' iyM^[/-R6
9、存储更改全部表 F|eu<^"$ H
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch SE `l(-tL
@OldOwner as NVARCHAR(128), *Z kss
@NewOwner as NVARCHAR(128) 3]}'TA`v
AS k$[{n'\@
DECLARE @Name as NVARCHAR(128) V/y=6wUiSl
DECLARE @Owner as NVARCHAR(128) 2w1tK
DECLARE @OwnerName as NVARCHAR(128) W"sr$K2m|
DECLARE curObject CURSOR FOR =HE
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select 'Name' = name, aWvd`qA9r
'Owner' = user_name(uid) kV)'a
from sysobjects 'DAltr<
where user_name(uid)=@OldOwner +WF.wP?y
order by name XVUf,N,
OPEN curObject LM1b I4
FETCH NEXT FROM curObject INTO @Name, @Owner -V=arm\#z
WHILE(@@FETCH_STATUS=0) f=ib9WbR#
BEGIN
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if @Owner=@OldOwner epVH.u%
begin xH$%5@~
set @OwnerName = @OldOwner + '.' + rtrim(@Name) Z{}+)Q*Q
exec sp_changeobjectowner @OwnerName, @NewOwner #v8Cy|I
end _i@x@:_l
-- select @name,@NewOwner,@OldOwner u2lmwE
FETCH NEXT FROM curObject INTO @Name, @Owner 1g i}H)
END $FCw$ +w
close curObject k+\7B}7F
deallocate curObject l<RfRqjw
GO V_]-`?S
10、SQL SERVER中直接循环写入数据 cEi<}9r
declare @i int 9p<:LZd~
set @i=1 Oxn'bh6R0
while @i<30 Q-Y@)Mf~?0
begin I"V3+2e
insert into test (userid) values(@i) tJ>d4A;8x
set @i=@i+1 >@Khm"/T
end S ljZ~x,!
小记存储过程中经常用到的本周,本月,本年函数 N7B}O*;
Dateadd(wk,datediff(wk,0,getdate()),-1) j?J=w=.Nx
Dateadd(wk,datediff(wk,0,getdate()),6) mt .,4
Dateadd(mm,datediff(mm,0,getdate()),0) ^V,@=QL3U
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) &|] Fg5
Dateadd(yy,datediff(yy,0,getdate()),0) nK:`e9ES
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) \]GGVI;u
上面的SQL代码只是一个时间段 F\P!NSFZV
Dateadd(wk,datediff(wk,0,getdate()),-1) 5oa]dco
Dateadd(wk,datediff(wk,0,getdate()),6) ndt8=6p
就是表示本周时间段. =z%s8D2
下面的SQL的条件部分,就是查询时间段在本周范围内的: Q
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) { r X5
而在存储过程中 oG9SO^v_
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 6KBHRt
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) CY\mU_.b