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。 >k'c'7/
kO}AxeQ
+t?3T-@Ks
一、基础 Xwhui4'w
1、说明:创建数据库 ( vca&wI!
CREATE DATABASE database-name 9T1ZL5
2、说明:删除数据库 u,UmrR
drop database dbname |]c8jG\h
3、说明:备份sql server DK$s&zf
--- 创建 备份数据的 device Qc pm!
USE master R;j!}D!4
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' :AE&Ny4
--- 开始 备份 xftBSdVE
BACKUP DATABASE pubs TO testBack *m#Za<_Gv
4、说明:创建新表 `5C,N!d8X
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) lR(+tj)9uO
根据已有的表创建新表: svq<)hAf<
A:create table tab_new like tab_old (使用旧表创建新表) D}mjN=Y
B:create table tab_new as select col1,col2... from tab_old definition only FAj)OTI2S
5、说明:删除新表 +1D+]*t_?[
drop table tabname 'L8'
'(eZ^
6、说明:增加一个列 R.yC(r
Alter table tabname add column col type i(NdGL#P
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 fP.
6HF_p_
7、说明:添加主键: Alter table tabname add primary key(col) sNLs\4v
说明:删除主键: Alter table tabname drop primary key(col) aXoVy&x=
8、说明:创建索引:create [unique] index idxname on tabname(col....) jJ5W>Q1mK$
删除索引:drop index idxname [Lzw#XE
注:索引是不可更改的,想更改必须删除重新建。 oomT)gO 6*
9、说明:创建视图:create view viewname as select statement 4B^ZnFJ%m
删除视图:drop view viewname } x2DT8u
10、说明:几个简单的基本的sql语句 fc
|GArL#}
选择:select * from table1 where 范围 aL&n[
插入:insert into table1(field1,field2) values(value1,value2) FGoy8+nB1M
删除:delete from table1 where 范围 _iir<}
更新:update table1 set field1=value1 where 范围 zlEX+=3
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! v^1pN>#%g
排序:select * from table1 order by field1,field2 [desc] BDjn
!3
总数:select count as totalcount from table1 0DJ+I
求和:select sum(field1) as sumvalue from table1 {PVW D7
平均:select avg(field1) as avgvalue from table1 4/wa+Y+=vt
最大:select max(field1) as maxvalue from table1 ,d {"m)r<
最小:select min(field1) as minvalue from table1
b4QI)z
IkGfnXJ
J%,*isEL
|563D#?cR
11、说明:几个高级查询运算词 [@5Ytv H
5.MGaU^Z$
sk=-M8;\
A: UNION 运算符 |v$JCU3!A
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 #3+!ee27#
B: EXCEPT 运算符 TL}++e
7+
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 (G[
*|6m
C: INTERSECT 运算符 )3>hhuaa
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 {qN 5MsY
注:使用运算词的几个查询结果行必须是一致的。 c1E'$-
K@
12、说明:使用外连接 6x%h6<#xh*
A、left outer join: |\7
ET[Xq
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。 ,&R/4:I
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 -}KC=,]vh
B:right outer join: Z7= `VNHc
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。 `.i!NBA'6
C:full outer join:
.p e( lP
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。 R
wZ]),o
1*@'-mj
Jz2N
二、提升 pP*a
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) $d_|NssvU
法一:select * into b from a where 1<>1 ;n&t>pBM
法二:select top 0 * into b from a OHhsP}/
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) +Zaj,oEE
insert into b(a, b, c) select d,e,f from b; T Kg aV;92
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) rV T{90,
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 i}B2R$Z3
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. >kW@~WDMu
4、说明:子查询(表名1:a 表名2:b) oz}+T(@O
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) U
G~b a
5、说明:显示文章、提交人和最后回复时间 +,#$:fs u
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b TzNn^ir=HX
6、说明:外连接查询(表名1:a 表名2:b) $3s@}vLd
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c '*"vkgN
7、说明:在线视图查询(表名1:a ) Nn T1X;0W
select * from (SELECT a,b,c FROM a) T where t.a > 1; *1fb}C_
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 % a@>_
select * from table1 where time between time1 and time2 w%JTTru
select a,b,c, from table1 where a not between 数值1 and 数值2 e,Uo#T6J
9、说明:in 的使用方法 pUV/Ul]
select * from table1 where a [not] in ('值1','值2','值4','值6') K*X_FJ
10、说明:两张关联表,删除主表中已经在副表中没有的信息 P_Gw-`L5T
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 )
(q(~de
11、说明:四表联查问题: *%S"eWb
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 ..... -)RH5WG S
12、说明:日程安排提前五分钟提醒 jAm3HI
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 +PcmJ
13、说明:一条sql 语句搞定数据库分页 c+hQSm|bf)
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 paD !Z0v&
14、说明:前10条记录 9Ru8~R/\
select top 10 * form table1 where 范围 B4i!/@0s
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.) g.zEn/SM
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) yL2o}ZbS
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
F)'.g d
(select a from tableA ) except (select a from tableB) except (select a from tableC) 0a-0Y&lQm
17、说明:随机取出10条数据 y"H*%]
select top 10 * from tablename order by newid() <U!`J[n%
18、说明:随机选择记录 tX>
G,hw
select newid() WRrd'{sB
19、说明:删除重复记录 )~HUo9K9
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) k{Me[B
20、说明:列出数据库里所有的表名 >o7n+Rb:
select name from sysobjects where type='U' rjp-Fw~1w
21、说明:列出表里的所有的 !U'QqnT
select name from syscolumns where id=object_id('TableName') L_wk~z
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。 i03w1pSH,
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 'gTb A?+@5
显示结果: RF%KA[Dj
type vender pcs ck.w
5|$
电脑 A 1 \v.C]{Gzc
电脑 A 1 (K)] qNH
光盘 B 2 Te<}*qvD
光盘 A 2 #]ypHVE
手机 B 3 :n.f_v}6
手机 C 3 >U]C/P[+
23、说明:初始化表table1 (3{YM(
TRUNCATE TABLE table1 to=y#$_
24、说明:选择从10到15的记录 'VlDh`<W
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 4:dH]
q&W[j5E
(}EB2V9Hh
L.jh
三、技巧 |ayVjqJ*
1、1=1,1=2的使用,在SQL语句组合时用的较多 }l],.J\BGX
"where 1=1" 是表示选择全部 "where 1=2"全部不选, @!yMIM%P
如: vA]W|sLF9
if @strWhere !='' q gLaa
begin [`c^4E
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere /qy-qUh3h
end 9Bw|(J
else 5
({t4dm
begin &'
Ne!o8
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 9&_<f}ou
end (<}&DE
我们可以直接写成 /q5v"iX]T
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 37|&?||
2、收缩数据库 3~S8!nx
--重建索引 EioB%f3
DBCC REINDEX 9&` 2V
DBCC INDEXDEFRAG b/{t|io{
--收缩数据和日志 *22nVKi{
DBCC SHRINKDB hR
Ue<0o:
DBCC SHRINKFILE [5+}rwm&W
3、压缩数据库 a+!tT!g&I
dbcc shrinkdatabase(dbname) 7lBAxqr2
4、转移数据库给新用户以已存在用户权限 .QN>z-YA6:
exec sp_change_users_login 'update_one','newname','oldname' pnbIiyV
go wT:b\km:!
5、检查备份集 Db1pW=66:
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Xt@Z}B))pu
6、修复数据库 cxr=k%~}J
ALTER DATABASE [dvbbs] SET SINGLE_USER N=QfP
GO Y!gCMLL
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK glF; eT
GO 8F&=a,ps[
ALTER DATABASE [dvbbs] SET MULTI_USER {O`w,dMOI
GO '4|-9M3f
7、日志清除 D~$r\]av
SET NOCOUNT ON #R.-KUW:
DECLARE @LogicalFileName sysname, NH<5*I/
@MaxMinutes INT, _q{c##Kf
@NewSize INT Ko&>C_N
USE tablename -- 要操作的数据库名 Gq }U|Z
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 =aoMii
@MaxMinutes = 10, -- Limit on time allowed to wrap log. viMzR(JU
@NewSize = 1 -- 你想设定的日志文件的大小(M) m|:_]/*qE
-- Setup / initialize T2!6(,
s9
DECLARE @OriginalSize int /x[jQM\
SELECT @OriginalSize = size 7|[mz> "d
FROM sysfiles vDxe/x%
WHERE name = @LogicalFileName yX0dbW~@y
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 8W#heW\-]
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + "t_-f7fS7
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' d
BJJZ^(
FROM sysfiles U2wbv Xr5-
WHERE name = @LogicalFileName V*iH}Y?^p
CREATE TABLE DummyTrans nY`RRC
(DummyColumn char (8000) not null) )Hk3A$6(
DECLARE @Counter INT, Hr]h
Jc
@StartTime DATETIME, IuRmEL_Q_
@TruncLog VARCHAR(255) y10h#&k
SELECT @StartTime = GETDATE(), ~ y;6W0x
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ?Vdia:
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 52,m:EhL
EXEC (@TruncLog) 5wh|=**/
-- Wrap the log if necessary. q11>f
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired MvWaB
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) x`dHJq`_g
AND (@OriginalSize * 8 /1024) > @NewSize FTQ%JTgT
BEGIN -- Outer loop. km1~yQ"bH
SELECT @Counter = 0 6N;wqn
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) -OA?BEQ=I
BEGIN -- update 0#S W!b|%
INSERT DummyTrans VALUES ('Fill Log') :C65-[PSdO
DELETE DummyTrans A0q|J/T
SELECT @Counter = @Counter + 1 3T}izG]
END ],JEBt
EXEC (@TruncLog) mA*AeP_$
END eZdu2.;<
SELECT 'Final Size of ' + db_name() + ' LOG is ' + JZD[N Z<
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + =<X?sj5
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' HOE_S!N
FROM sysfiles a8i]]1Blz
WHERE name = @LogicalFileName [vHv0"
DROP TABLE DummyTrans /Ya_>+oo
SET NOCOUNT OFF NCk r /#!
8、说明:更改某个表 =UJ:t Sr
exec sp_changeobjectowner 'tablename','dbo' (v}>tb*#`
9、存储更改全部表 PV4(hj
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 3+G@g#MY
@OldOwner as NVARCHAR(128), 8$ma;U d
@NewOwner as NVARCHAR(128) (s7;^)}zx
AS EVVP]ND
DECLARE @Name as NVARCHAR(128) S!G(a"<W
DECLARE @Owner as NVARCHAR(128) /`6ZAom9
DECLARE @OwnerName as NVARCHAR(128) "gne_Ye.
DECLARE curObject CURSOR FOR qLT>Mz)$%
select 'Name' = name, 3`ELKq
'Owner' = user_name(uid) `^FGwx@
from sysobjects bV$)!]V
where user_name(uid)=@OldOwner G1"zElug
order by name D[mSmpjE6&
OPEN curObject O Vko+X`
FETCH NEXT FROM curObject INTO @Name, @Owner tdSfi<y5I
WHILE(@@FETCH_STATUS=0) Ar:*oiU
BEGIN !2'jrJGc
if @Owner=@OldOwner L?Qg#YSd~
begin (
|PAx(
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 7"w2$*4 '0
exec sp_changeobjectowner @OwnerName, @NewOwner 3`B6w$z>(
end L.2/*H#
-- select @name,@NewOwner,@OldOwner QzzW x2
FETCH NEXT FROM curObject INTO @Name, @Owner CFqJ/''
END "E8zh|m o
close curObject ;+<&8.=,)
deallocate curObject 1!1beR]
GO &b?LP]
10、SQL SERVER中直接循环写入数据 ALNc'MW!
declare @i int -Gw$#!
set @i=1 1QU:?_\6@t
while @i<30 <X7FMNr[
begin Jnna$6G)B
insert into test (userid) values(@i) L\&<sy"H
set @i=@i+1 MwR0@S}*
end t0nI ('LX,
小记存储过程中经常用到的本周,本月,本年函数 NyVnA
Dateadd(wk,datediff(wk,0,getdate()),-1) N#Zhxu,g!
Dateadd(wk,datediff(wk,0,getdate()),6) ^H2-RBE#
Dateadd(mm,datediff(mm,0,getdate()),0) 20iq2
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) :w<V
Dateadd(yy,datediff(yy,0,getdate()),0) 839IRM@'5
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) qZh1`\G
上面的SQL代码只是一个时间段 ;IVDr:
Dateadd(wk,datediff(wk,0,getdate()),-1) DVK)2La
Dateadd(wk,datediff(wk,0,getdate()),6) C#t'Y*
就是表示本周时间段. 9XRZ$j}L
下面的SQL的条件部分,就是查询时间段在本周范围内的: t7m>A-I
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) |pmZ.r
而在存储过程中 LwK+:4$
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) u)V#S:9]
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) q&Gz ]