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。 uJ<nW%}
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一、基础 f'&30lF
1、说明:创建数据库 ]S;^QZ
CREATE DATABASE database-name dS]TTU1
2、说明:删除数据库 ,l/~epx4v)
drop database dbname hG51jVYtw
3、说明:备份sql server Lc 4\i
--- 创建 备份数据的 device ?#~3%$>
USE master lZ]x #v
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' tQ0iie1Ys
--- 开始 备份 q2 K@i*s
BACKUP DATABASE pubs TO testBack dd1CuOd6(1
4、说明:创建新表 KG9h
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) r+%:rFeX
根据已有的表创建新表:
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A:create table tab_new like tab_old (使用旧表创建新表) }dcXuX4{r
B:create table tab_new as select col1,col2... from tab_old definition only Hl-!rP.?0
5、说明:删除新表 ?^I\e{),c
drop table tabname IxN0m7
6、说明:增加一个列 _2u RY
Alter table tabname add column col type !bs{/?
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 V&nTf 100
7、说明:添加主键: Alter table tabname add primary key(col) .m%/JquMFM
说明:删除主键: Alter table tabname drop primary key(col) E57:ap)/
8、说明:创建索引:create [unique] index idxname on tabname(col....) 6r
删除索引:drop index idxname );EW(7KeL
注:索引是不可更改的,想更改必须删除重新建。 XG_h\NIL
9、说明:创建视图:create view viewname as select statement %]NaHf
删除视图:drop view viewname 6{Y3-Pxg
10、说明:几个简单的基本的sql语句 B-'oB>|
选择:select * from table1 where 范围 NqyKR&;
插入:insert into table1(field1,field2) values(value1,value2) uP|Py.+
删除:delete from table1 where 范围 :yg:sU
更新:update table1 set field1=value1 where 范围 PP/EZ ^]b
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! PF=BXY1<UL
排序:select * from table1 order by field1,field2 [desc] qyi5j0)W
总数:select count as totalcount from table1 B=)&43)\
求和:select sum(field1) as sumvalue from table1 t6-He~
平均:select avg(field1) as avgvalue from table1 DD 8uG`<
最大:select max(field1) as maxvalue from table1 /$a>f>EJ
最小:select min(field1) as minvalue from table1 mL\_C9k,n
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11、说明:几个高级查询运算词 Dxp8^VL
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A: UNION 运算符 dL{zU4iUR
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。 7b>FqW)%
B: EXCEPT 运算符 aC$-riP,?'
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 Y]>!uwn
C: INTERSECT 运算符 4}0DEH.Vx
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 U|tUX)9O
注:使用运算词的几个查询结果行必须是一致的。 aqL#g18
12、说明:使用外连接 3JhT
A、left outer join: GxH]
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 NMaZ+g!t(
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c rq#8}T>
B:right outer join: {WokH;a/
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 `Wc"Ix0
C:full outer join: ZiR },F/
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 z=\y)'b
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二、提升 ]0[Gc
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 7kiZFHV
法一:select * into b from a where 1<>1 Ih Yso7g
法二:select top 0 * into b from a F+
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ~yX8p7qr
insert into b(a, b, c) select d,e,f from b; 1P8XVI'
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) ^a>3U l{
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 eXs^YPi
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. _:N+mEF
4、说明:子查询(表名1:a 表名2:b) ub/Z'!
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) `.oWmBey\
5、说明:显示文章、提交人和最后回复时间 L@mNfLK
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b kmNa),`{s
6、说明:外连接查询(表名1:a 表名2:b) ^Om0~)"q
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c \xCI8 *W
7、说明:在线视图查询(表名1:a ) ?=u/&3Cw
select * from (SELECT a,b,c FROM a) T where t.a > 1; JAt$WW{
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 Rs$fNW@P
select * from table1 where time between time1 and time2 8|]r>L$Wk
select a,b,c, from table1 where a not between 数值1 and 数值2 o7:~C]
9、说明:in 的使用方法 RN,5>.w
select * from table1 where a [not] in ('值1','值2','值4','值6') 8>R 75dw
10、说明:两张关联表,删除主表中已经在副表中没有的信息 gKPqWh
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ,\){-H/n
11、说明:四表联查问题: 6[.#B!;9
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 ..... 2SjH7
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12、说明:日程安排提前五分钟提醒 )GT*HJR(vc
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 c+BD37S
13、说明:一条sql 语句搞定数据库分页
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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 u"$=:GK
14、说明:前10条记录 7LFJi@*8
select top 10 * form table1 where 范围 F.rNh`44
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) OM>,1;UH]
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) YLXLaC[
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 Gt4/ax:A@
(select a from tableA ) except (select a from tableB) except (select a from tableC) `s )-
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17、说明:随机取出10条数据 UO1WtQyu,H
select top 10 * from tablename order by newid() FRBW(vKE
18、说明:随机选择记录 v|K,
select newid() :D|5E>o(
19、说明:删除重复记录 W?>C$_p C
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) [TW?sW^0
20、说明:列出数据库里所有的表名 GgU8f0I
select name from sysobjects where type='U' KF .O>c87&
21、说明:列出表里的所有的 lRk)
select name from syscolumns where id=object_id('TableName') g)3HVAT
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。 Vx
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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 (^{tu89ab
显示结果: '3i,^g0?t0
type vender pcs ]2_b_ok
电脑 A 1 _ww>u""B~
电脑 A 1 Za110oF
光盘 B 2 ~M c'~:{O
光盘 A 2 ]NEr]sc-"F
手机 B 3 cD%_+@GaU
手机 C 3 S|jE1v"L
23、说明:初始化表table1 L2sUh+'|
TRUNCATE TABLE table1 o^efeI
24、说明:选择从10到15的记录 gTM*td(~^
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc [
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三、技巧 mi';96
1、1=1,1=2的使用,在SQL语句组合时用的较多 LJ8 t@ui
"where 1=1" 是表示选择全部 "where 1=2"全部不选, gh?3 [q6
如: Nc da~h
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if @strWhere !='' g7UZtpLTm
begin 4\_~B{kzZ
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere k4E2OyCFoJ
end '+s ?\X4VC
else R9&3QRW|
begin +QW|8b
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' '=WPi_Z5:C
end FUO 9jX
我们可以直接写成 w-j^jU><3
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere L-9AJk>V
2、收缩数据库 c%+_~iBUN
--重建索引 o#Viz:
DBCC REINDEX u]z87#4
DBCC INDEXDEFRAG PY@BgL=/
--收缩数据和日志 Dq~\U&U\$
DBCC SHRINKDB '% if< /
DBCC SHRINKFILE /prR;'ks
3、压缩数据库 w7%.EA{N
dbcc shrinkdatabase(dbname) 1RgERj
4、转移数据库给新用户以已存在用户权限 jhJ'fI
exec sp_change_users_login 'update_one','newname','oldname' FX
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go v;sWI"Fv!
5、检查备份集 |muZv!,E
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' vf@toYc[E
6、修复数据库 B'v~0Kau
ALTER DATABASE [dvbbs] SET SINGLE_USER 3
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GO xxQgX~'x
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK V<i_YLYmJe
GO <~Oy3#{
ALTER DATABASE [dvbbs] SET MULTI_USER AX] cM)w
GO OQJ#>*?
7、日志清除 6QYHPz
SET NOCOUNT ON "(YfvO+
DECLARE @LogicalFileName sysname, #z5$_z?_
@MaxMinutes INT, so>jz@!EE
@NewSize INT ]@6L,+W"
USE tablename -- 要操作的数据库名 8~}~d}wW
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 }rQ0*h
@MaxMinutes = 10, -- Limit on time allowed to wrap log. JKF/z@Vbe\
@NewSize = 1 -- 你想设定的日志文件的大小(M) pt%*Y.)az
-- Setup / initialize !"LFeqI$lr
DECLARE @OriginalSize int =.]{OT
SELECT @OriginalSize = size b:Tv
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FROM sysfiles iOB*K)U1
WHERE name = @LogicalFileName $Xr4=9(|7
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ;r BbLM`
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + FmhT^
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 4g)$(5jI}
FROM sysfiles W) ?s''WE;
WHERE name = @LogicalFileName F|&%Z(@a
CREATE TABLE DummyTrans 4d8}g25C
(DummyColumn char (8000) not null) +&4@HHU{G
DECLARE @Counter INT, &U_T1-UR2
@StartTime DATETIME, mM2DZ^"j(
@TruncLog VARCHAR(255) EEP&Y?
SELECT @StartTime = GETDATE(), Od+nBJ
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' jpkKdQX)
DBCC SHRINKFILE (@LogicalFileName, @NewSize) wCEcMVT
EXEC (@TruncLog) (,R\6
-- Wrap the log if necessary. A\})H
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired U.Fs9F4M #
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) F*JbTEOn
AND (@OriginalSize * 8 /1024) > @NewSize jGUegeq
BEGIN -- Outer loop. b=kY9!GN,v
SELECT @Counter = 0 L>n^Q:M
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) %RIlu[J
BEGIN -- update Rxq4Diq5k
INSERT DummyTrans VALUES ('Fill Log') gbu*6&j9
DELETE DummyTrans q\/xx`L
SELECT @Counter = @Counter + 1 AHzm9U @
END mYFc53B
EXEC (@TruncLog) $wcTUl
END G6bvV*TRi
SELECT 'Final Size of ' + db_name() + ' LOG is ' + .\+c{
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + p{x6BVw?>
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' Gce[RB:
FROM sysfiles -XfGF<}r
WHERE name = @LogicalFileName F8xu&Vk0:
DROP TABLE DummyTrans e8&7W3 m
SET NOCOUNT OFF bQ-n<Lx
8、说明:更改某个表 `-g$
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exec sp_changeobjectowner 'tablename','dbo' XPLm`Q|1#t
9、存储更改全部表 w>4( hGO
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ^ f[^.k$3d
@OldOwner as NVARCHAR(128), y/>Nx7C0=2
@NewOwner as NVARCHAR(128) BKK@_B"
AS mGoNT
DECLARE @Name as NVARCHAR(128) I9h{fB
DECLARE @Owner as NVARCHAR(128) qOAhBZ~
DECLARE @OwnerName as NVARCHAR(128) #V.u[:mO
DECLARE curObject CURSOR FOR XEUS)X)
select 'Name' = name, %edTW[C`
'Owner' = user_name(uid) L>pSE'}
from sysobjects ~i0>[S3'
where user_name(uid)=@OldOwner O&Y22mu
order by name b_)SMAsO7
OPEN curObject #n+sbx5~7
FETCH NEXT FROM curObject INTO @Name, @Owner Of#"nu
WHILE(@@FETCH_STATUS=0) tm.&k6%
BEGIN \[
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if @Owner=@OldOwner S[CWrPaDQ
begin X=? \A{Y
set @OwnerName = @OldOwner + '.' + rtrim(@Name) _TyQC1 d
exec sp_changeobjectowner @OwnerName, @NewOwner v}<z_i5/C.
end CoV@{Pi
-- select @name,@NewOwner,@OldOwner s>=$E~qq
FETCH NEXT FROM curObject INTO @Name, @Owner Pk5 %lu
END ;x&3tN/I
close curObject ?4t~z 1.f
deallocate curObject GL^
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GO @ev^e!B
10、SQL SERVER中直接循环写入数据 }OSf C~5P
declare @i int yMOYTN@]
set @i=1 D=B :tP
while @i<30 xR;z!Tg)
begin 'cY@Dqg1
insert into test (userid) values(@i) W+.?J
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set @i=@i+1 #2+hu^Q-
end kdMB.~(K=
小记存储过程中经常用到的本周,本月,本年函数 d;a"rq@a)
Dateadd(wk,datediff(wk,0,getdate()),-1) Is97>aid
Dateadd(wk,datediff(wk,0,getdate()),6) )+.AgqxI
Dateadd(mm,datediff(mm,0,getdate()),0) 9Dyw4'W.N
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) xzRC %
Dateadd(yy,datediff(yy,0,getdate()),0) BbI),iP
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) lEpPi@2PK
上面的SQL代码只是一个时间段 yCv"(fNQ
Dateadd(wk,datediff(wk,0,getdate()),-1) 7KtgR=-Lb
Dateadd(wk,datediff(wk,0,getdate()),6) 7>gW2m
就是表示本周时间段. cSj(u%9}
下面的SQL的条件部分,就是查询时间段在本周范围内的: O>ZJOKe
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) r?x~`C
而在存储过程中 |\]pTA$2
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) TSsx^h8/
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) )' 2vUt`_7