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。 X7g1:L1Ys
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一、基础 KFwzy U"
1、说明:创建数据库 x3"#POp
CREATE DATABASE database-name Zc`BiLzrIG
2、说明:删除数据库 #gcF"L||
drop database dbname se>MQM5 )
3、说明:备份sql server '&|=0TDd+
--- 创建 备份数据的 device _Iv6pNd/
USE master %$Aqle[
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' =Fr(9(
--- 开始 备份 PuZf/um
BACKUP DATABASE pubs TO testBack 6<ZkJ:=
4、说明:创建新表 o$Z6zm xO
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) b^$|Nz;
根据已有的表创建新表: DY?Kfvef
A:create table tab_new like tab_old (使用旧表创建新表) |Xk4&sDrK
B:create table tab_new as select col1,col2... from tab_old definition only Z7?~S2{c
5、说明:删除新表 '`uwJ&@
drop table tabname wL:flH@
6、说明:增加一个列 3z&Fi;<+j
Alter table tabname add column col type "UJ
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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。 & J2M1z%
7、说明:添加主键: Alter table tabname add primary key(col) f|tjsZxQ
说明:删除主键: Alter table tabname drop primary key(col) 9BuSN*4
8、说明:创建索引:create [unique] index idxname on tabname(col....) /Dj=iBO
删除索引:drop index idxname 8!Ww J
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注:索引是不可更改的,想更改必须删除重新建。 u[
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9、说明:创建视图:create view viewname as select statement 6gs01c,BA
删除视图:drop view viewname
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10、说明:几个简单的基本的sql语句 |YY_^C`"-
选择:select * from table1 where 范围 &E=>Hj(dTG
插入:insert into table1(field1,field2) values(value1,value2) UaB @
删除:delete from table1 where 范围 q*7VqB
更新:update table1 set field1=value1 where 范围 wLOB}ZMT
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 9^G/8<^^>
排序:select * from table1 order by field1,field2 [desc] Aw5HF34J
总数:select count as totalcount from table1
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求和:select sum(field1) as sumvalue from table1 Gnq?"</
平均:select avg(field1) as avgvalue from table1 }=]M2}
最大:select max(field1) as maxvalue from table1 3S}Pm2D2
最小:select min(field1) as minvalue from table1 w_{wBL[3e
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11、说明:几个高级查询运算词 \hEN4V[
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A: UNION 运算符 A*/HjTX
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。 O2%?
B: EXCEPT 运算符 :1bWVM)
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。 D5*q7A6
C: INTERSECT 运算符 `,(,tn_
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。 ZGKu>yM
注:使用运算词的几个查询结果行必须是一致的。 uW}s)j.
12、说明:使用外连接 !*%WuyCgr4
A、left outer join: ZP\-T*)l$
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。 /VN f{p
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 +yD`3`
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B:right outer join: sv&;Y\2c
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。 B2'i7Ps
C:full outer join: EKsT~SS
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。 ;k>&FWEG
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二、提升 r 0iK
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) l)&X$3? tz
法一:select * into b from a where 1<>1 ''\Ov
法二:select top 0 * into b from a Dw<bn<e-
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) +N:o-9
insert into b(a, b, c) select d,e,f from b; zM(vr"U
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) =aBctd:eX`
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ne_TIwf w-
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. t~#zMUfac
4、说明:子查询(表名1:a 表名2:b) mSb#Nn6W
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) Ke2ccN
5、说明:显示文章、提交人和最后回复时间 [VsKa\9u
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b HTS%^<u
6、说明:外连接查询(表名1:a 表名2:b) E4~<V=2l
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c l^pA2yh|
7、说明:在线视图查询(表名1:a ) li}1S
select * from (SELECT a,b,c FROM a) T where t.a > 1; h1B16)
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 r[b(I@T+
select * from table1 where time between time1 and time2 SfaQvstN
select a,b,c, from table1 where a not between 数值1 and 数值2 $4 S@
9、说明:in 的使用方法 [nrYpb4
select * from table1 where a [not] in ('值1','值2','值4','值6') G?;e-OhV
10、说明:两张关联表,删除主表中已经在副表中没有的信息 f-`)^5E
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) fj;y}t1E]
11、说明:四表联查问题: $',K7%y
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 ..... z4jR[x,
12、说明:日程安排提前五分钟提醒 lrIS{MJ+-
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 &)AVzN+*h
13、说明:一条sql 语句搞定数据库分页 j)/nKh4O
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 c*L0@Ak%
14、说明:前10条记录 YSTv\y
select top 10 * form table1 where 范围 6sx'S?Qa*
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.) rMLp-aR'
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) $JMXV
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 %&w3;d;c
(select a from tableA ) except (select a from tableB) except (select a from tableC) Wp!%-vzy&
17、说明:随机取出10条数据 XH}\15X
select top 10 * from tablename order by newid() |ZRagn30
18、说明:随机选择记录 lFV N07hG
select newid() 6i.-6></
19、说明:删除重复记录 ]pNvxXbeW
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) hog=ut
20、说明:列出数据库里所有的表名 pEIRh1
select name from sysobjects where type='U' GS a[
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21、说明:列出表里的所有的 )GM41t1i
select name from syscolumns where id=object_id('TableName') ujR_"r|l
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。 JNt^ (z
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 r0+6evU2
显示结果: 6/r)y+H
type vender pcs +#lM
电脑 A 1 ^h~x)@=
电脑 A 1 `lO[x.[
光盘 B 2 kT"Kyd
光盘 A 2 +'I+o5*
手机 B 3 3L_\`Ia9
手机 C 3 W;'!gpa
23、说明:初始化表table1 VcSVu
TRUNCATE TABLE table1 \KQ71yqY
24、说明:选择从10到15的记录 +zaA,e?\
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 5qZ1FE
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三、技巧 2[RoxKm
1、1=1,1=2的使用,在SQL语句组合时用的较多 %.^_Ps0
"where 1=1" 是表示选择全部 "where 1=2"全部不选, T_@K&<
如: @` 1Ds
if @strWhere !='' 17oa69G
begin Q@<S[Qh[.
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere S+atn]eU@
end VC\ S'z
else \n8]M\<
begin T|7}EAR=b
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' .<x&IJ /
end q_g+Jf
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我们可以直接写成 GT }F9F~
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere jV>raCK_
2、收缩数据库 B8V>NvE~o
--重建索引 4E]l{"k<
DBCC REINDEX aWWU4xe
DBCC INDEXDEFRAG mKL<<L[
--收缩数据和日志 Li/O
DBCC SHRINKDB rV R1wsaL
DBCC SHRINKFILE Mc09ES
3、压缩数据库 5Iy;oZ
dbcc shrinkdatabase(dbname) zr+zhpp
4、转移数据库给新用户以已存在用户权限 u09:Z{tL;@
exec sp_change_users_login 'update_one','newname','oldname' -0$55pa/@:
go >VP=MbN
5、检查备份集 ^;Y|3)vvB
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' vY }A
6、修复数据库 TZ(cu>
ALTER DATABASE [dvbbs] SET SINGLE_USER G-xDN59K
GO P"y`A}Bx
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK / ';0H_
GO juka0/
ALTER DATABASE [dvbbs] SET MULTI_USER zR1^I~
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GO @z4*.S&tz
7、日志清除 544X1Ww2
SET NOCOUNT ON Pe3@d|-,MU
DECLARE @LogicalFileName sysname, XC0bI,Fu,
@MaxMinutes INT, wkA+j9.
@NewSize INT .aAL]-Rj
USE tablename -- 要操作的数据库名 [SHXJ4P*
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 %k-3?%&8
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ein4^o<f.
@NewSize = 1 -- 你想设定的日志文件的大小(M) Kwefs;<E?
-- Setup / initialize \Xm,OE_v"
DECLARE @OriginalSize int "?ucO4d
SELECT @OriginalSize = size ewa wL"
FROM sysfiles -8:&>~4`
WHERE name = @LogicalFileName -+ SF
SELECT 'Original Size of ' + db_name() + ' LOG is ' + Co (.:z~
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + iOR_[ y,
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 3L833zL
FROM sysfiles zLD0RBj7p
WHERE name = @LogicalFileName v0-cd
CREATE TABLE DummyTrans /<@SFF.
(DummyColumn char (8000) not null) tZ=E')!\
DECLARE @Counter INT, k9 "[H'
@StartTime DATETIME, {sihus#Q
@TruncLog VARCHAR(255) "!Uqcay-
SELECT @StartTime = GETDATE(), n[ T[DCQ,
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' iVp,e
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ;>
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EXEC (@TruncLog) ~$iIVJ`
-- Wrap the log if necessary. ])|d"[ur=
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired //T>G_1
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) )PG6gZYW
AND (@OriginalSize * 8 /1024) > @NewSize T]t+E'sQ
BEGIN -- Outer loop. A )^`?m3
SELECT @Counter = 0 GN ]cDik
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ]ndvt[4L
BEGIN -- update 9xO#tu]
INSERT DummyTrans VALUES ('Fill Log') <j&DK2u=i
DELETE DummyTrans p2n0Z\2
SELECT @Counter = @Counter + 1 @hJ%@(
END |]J>R
EXEC (@TruncLog) l>Z5 uSG
END .z)%)PVV
SELECT 'Final Size of ' + db_name() + ' LOG is ' + w[9|cgCY
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Bg&i63XL$$
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' /2UH=Q!x4E
FROM sysfiles ;A|-n1e>Hc
WHERE name = @LogicalFileName 0y
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DROP TABLE DummyTrans -BRc8 /
SET NOCOUNT OFF bSfpbo4(
8、说明:更改某个表 6|aKL[%6
exec sp_changeobjectowner 'tablename','dbo' jGXO\:sO
9、存储更改全部表 ofPHmh`
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch UUzYbuS>&l
@OldOwner as NVARCHAR(128), ap&?r`Tu
@NewOwner as NVARCHAR(128) i=i(%yQ%
AS v@Gl|29_
DECLARE @Name as NVARCHAR(128) "}q@Y=
DECLARE @Owner as NVARCHAR(128) OK{quM5
DECLARE @OwnerName as NVARCHAR(128) tSVc|j
DECLARE curObject CURSOR FOR qQA}Z*(m
select 'Name' = name, k5D%y3|9
'Owner' = user_name(uid) (@%gS[]
from sysobjects V.O(S\
where user_name(uid)=@OldOwner xl6,s>ob
order by name giZP.C"0
OPEN curObject +Vm}E0Ov
FETCH NEXT FROM curObject INTO @Name, @Owner o*DN4oa)
WHILE(@@FETCH_STATUS=0) r G4';V^q
BEGIN MS\>DW
if @Owner=@OldOwner !G SV6
begin v%"|WV[N
set @OwnerName = @OldOwner + '.' + rtrim(@Name) e?7&M
exec sp_changeobjectowner @OwnerName, @NewOwner D}dn.$
end iVB86XZ`
-- select @name,@NewOwner,@OldOwner wF|fK4F
FETCH NEXT FROM curObject INTO @Name, @Owner NWM8[dI
END V n*
close curObject xnmmXtk
deallocate curObject jp0<pw_
GO ` D= S{
10、SQL SERVER中直接循环写入数据 S/D^
declare @i int R]OpQ[k
set @i=1 )z&/_E=
while @i<30 'NX```U0
begin .q9
$\wM/
insert into test (userid) values(@i) 7w'wjX-
set @i=@i+1 ep2k%?CX 1
end a^`rtvT
小记存储过程中经常用到的本周,本月,本年函数 3):A
Dateadd(wk,datediff(wk,0,getdate()),-1) N F+iza;DP
Dateadd(wk,datediff(wk,0,getdate()),6) y^%n'h{
Dateadd(mm,datediff(mm,0,getdate()),0) ?YZ- P{rTS
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) /Y'Vh^9/T
Dateadd(yy,datediff(yy,0,getdate()),0) "br,/Dk>MX
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) |962G1.
上面的SQL代码只是一个时间段 }UWL-TkEjF
Dateadd(wk,datediff(wk,0,getdate()),-1) *QLI3B9V
Dateadd(wk,datediff(wk,0,getdate()),6) :P<]+\m
就是表示本周时间段. VxVE
下面的SQL的条件部分,就是查询时间段在本周范围内的: <-[wd.M_
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) CbwJd5tk
而在存储过程中 89o/F+ _b
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1)
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) YhDtUt}?