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。 |m)kN2w
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一、基础 fxd0e;NAAh
1、说明:创建数据库 }k7_'p&yk
CREATE DATABASE database-name YGp)Oy}:
2、说明:删除数据库 bHE7yv [
drop database dbname \7Qb229?
3、说明:备份sql server 'f+NW&
--- 创建 备份数据的 device dy2rkV.z
USE master " !-Kd'V
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' }# Doy{T
--- 开始 备份 yoQ\lk
BACKUP DATABASE pubs TO testBack C`QzT{6!
4、说明:创建新表 XV>@B $hu
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 'Dath>Y=
根据已有的表创建新表: }$&xTW_
A:create table tab_new like tab_old (使用旧表创建新表) D<bI2
B:create table tab_new as select col1,col2... from tab_old definition only G(/DtY]
5、说明:删除新表 %?9Ok
drop table tabname T/l1qcf`wT
6、说明:增加一个列 (Sv>NQp
Alter table tabname add column col type v*z(@<Y
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。 .IgRY\?Q
7、说明:添加主键: Alter table tabname add primary key(col) K*Ks"Vx
说明:删除主键: Alter table tabname drop primary key(col) <r~wZ}s
8、说明:创建索引:create [unique] index idxname on tabname(col....) [} -3PpF
删除索引:drop index idxname xzm@
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注:索引是不可更改的,想更改必须删除重新建。 e\F}q)_
9、说明:创建视图:create view viewname as select statement G>w+#{(
删除视图:drop view viewname F}36IM9/:
10、说明:几个简单的基本的sql语句 o5!f#Y
选择:select * from table1 where 范围 ~jN'J+_$
插入:insert into table1(field1,field2) values(value1,value2) eh(<m8I
删除:delete from table1 where 范围 SJk>Jt=
更新:update table1 set field1=value1 where 范围 A_R!uRD8-
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! /:Lu_)5
排序:select * from table1 order by field1,field2 [desc] kccWoU,
总数:select count as totalcount from table1 Y/fJQ6DY
求和:select sum(field1) as sumvalue from table1 k_ Y~;P@
平均:select avg(field1) as avgvalue from table1 Dz;HAyPj
最大:select max(field1) as maxvalue from table1 MzkkcQLK
最小:select min(field1) as minvalue from table1 XN;&qR^j
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11、说明:几个高级查询运算词 q/PNJ#<
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A: UNION 运算符 eKG2*CV
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。 Zb_apjg[4
B: EXCEPT 运算符 =:=/Gz1
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。 =-#G8L%Q
C: INTERSECT 运算符 QR0(,e$Dl
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 h/)_)
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注:使用运算词的几个查询结果行必须是一致的。 |^a;77nE_^
12、说明:使用外连接 _mJG5(|
A、left outer join: ]*N1t>fb
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。
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SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c e,gyQjJR
B:right outer join: pHC/(6?
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 7K;!iX<d
C:full outer join: @?kJ).
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 )C~9E 5E
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二、提升 h4)Bs\==mT
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) [XR$F@o
法一:select * into b from a where 1<>1 xZ .!d.rn
法二:select top 0 * into b from a np9dM
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) &7>zURv
insert into b(a, b, c) select d,e,f from b; 56}X/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) $B (kZ
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 33Az$GXFsq
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 8b(!k FxD
4、说明:子查询(表名1:a 表名2:b) 7DD&~ZcD
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) "_1)CDqP
5、说明:显示文章、提交人和最后回复时间 J G$Z.s
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b I&VTW8jB
6、说明:外连接查询(表名1:a 表名2:b) zjl!9M!
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c h6:#!Rg
7、说明:在线视图查询(表名1:a ) [?0d~Q(R#
select * from (SELECT a,b,c FROM a) T where t.a > 1; 5's~>up&
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 l'[A?%L%{
select * from table1 where time between time1 and time2 zM#sOg
select a,b,c, from table1 where a not between 数值1 and 数值2 H t(n%;<
9、说明:in 的使用方法 j5$GFi\kB
select * from table1 where a [not] in ('值1','值2','值4','值6') Na{Y}0=^y
10、说明:两张关联表,删除主表中已经在副表中没有的信息 L2UsqVU
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 1q7tiMvV-
11、说明:四表联查问题: }baR5v
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 ..... UL$}{2N,_
12、说明:日程安排提前五分钟提醒 ?)D^~/
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 b KtD"JG\
13、说明:一条sql 语句搞定数据库分页 6gL-OJNo
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 T{v>-xBRy
14、说明:前10条记录 w_tJ7pz8T
select top 10 * form table1 where 范围 &@FhR#pUQ
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.) pCi#9=?N
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Smw QET<H
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 h^UKT`9vt
(select a from tableA ) except (select a from tableB) except (select a from tableC) zi@]83SS#
17、说明:随机取出10条数据 cVnJ^*Z
select top 10 * from tablename order by newid() qet>1<
18、说明:随机选择记录 o 5U(i
select newid() X}ma]
19、说明:删除重复记录 $sHP\{
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) )!:sFa
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20、说明:列出数据库里所有的表名 \3f&7wU
select name from sysobjects where type='U' ]`g@UtD9`
21、说明:列出表里的所有的 W-Hoyn>?2
select name from syscolumns where id=object_id('TableName') co8"sz0(U
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 ').}N z
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type ypOLp SYk
显示结果: kYzKU2T\W
type vender pcs "Jq8?FoT
电脑 A 1 (V`Md\NL`
电脑 A 1 K<`osdp=&
光盘 B 2 : 18KR*;p
光盘 A 2 !9Z r;K~\
手机 B 3 m0n)dje
手机 C 3 l7H
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23、说明:初始化表table1 YyAJ m^o
TRUNCATE TABLE table1 \NZIEu)5?
24、说明:选择从10到15的记录 bNs4 5hDP
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc w'MGA
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三、技巧
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1、1=1,1=2的使用,在SQL语句组合时用的较多 YHkcWz
"where 1=1" 是表示选择全部 "where 1=2"全部不选, GPz(j'jU
如: JF&$t}
if @strWhere !='' K.<.cJE
begin i9<pqQ
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ygJr=_iA9
end JxE53ev
else i':ydDOOHA
begin 58\&/lYW
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' XR2~Q)@
end ZYU=\
我们可以直接写成 `*", <
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere #6Fez`A
2、收缩数据库 'm1N/)F
--重建索引 ,mhQ"\ +C
DBCC REINDEX ^bg2[FV
DBCC INDEXDEFRAG LEMfG~Czq
--收缩数据和日志 3~ S'LxV
DBCC SHRINKDB ( wDm*bZ*
DBCC SHRINKFILE {'?)FX*W
3、压缩数据库 A1'hlAGF
dbcc shrinkdatabase(dbname) )'17r82a
4、转移数据库给新用户以已存在用户权限 <h%O?mkC
exec sp_change_users_login 'update_one','newname','oldname' N{
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go An;MVA
5、检查备份集 5pr"d@.
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' MYJg8 '[j
6、修复数据库 m(RXJORI
ALTER DATABASE [dvbbs] SET SINGLE_USER *n"/a{6>
GO z%MW!x
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK *f&EoUk}F
GO {!6/x9>
ALTER DATABASE [dvbbs] SET MULTI_USER ku$$ 1xq
GO S}APQ
7、日志清除 JD@J[YY5R
SET NOCOUNT ON Tc8un.
DECLARE @LogicalFileName sysname, N\:.
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@MaxMinutes INT, eP*lI<NQ1
@NewSize INT { eCC$&"
USE tablename -- 要操作的数据库名 m'P1BLk
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. /VmR<C?h
@NewSize = 1 -- 你想设定的日志文件的大小(M) R\o<7g-|
-- Setup / initialize ee%fqVQ8P
DECLARE @OriginalSize int _ZY)M
SELECT @OriginalSize = size HGm 3+,
FROM sysfiles O3TQixE
WHERE name = @LogicalFileName =]:> "_jN
SELECT 'Original Size of ' + db_name() + ' LOG is ' + Ee`1F#c
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + !x!07`+^u
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' t]7&\ihZi~
FROM sysfiles 4`JH&))}
WHERE name = @LogicalFileName n1!?"m!
CREATE TABLE DummyTrans (Qa/EkE^*w
(DummyColumn char (8000) not null) Cmc3k,t
DECLARE @Counter INT, ,%\o4Rc'o
@StartTime DATETIME, t#q<n:WeYU
@TruncLog VARCHAR(255) pZ/>[TP(%F
SELECT @StartTime = GETDATE(), !rqF}d
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' /~ x"wo
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ;&1V0U,fx
EXEC (@TruncLog) 1V8-^
-- Wrap the log if necessary. {?'fyEeg
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired h/~n\0,J/
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) N[k wO1
AND (@OriginalSize * 8 /1024) > @NewSize ?LvCR_D:
BEGIN -- Outer loop. zZVfj:i8
SELECT @Counter = 0 xg)v0y~
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) E<yW\
BEGIN -- update )M)7"PC
INSERT DummyTrans VALUES ('Fill Log') v|U(+O
DELETE DummyTrans ZDbc
SELECT @Counter = @Counter + 1 *S/_i-ony
END H$I=W>;
EXEC (@TruncLog) JV;OGh>
END ]T%rjsN
SELECT 'Final Size of ' + db_name() + ' LOG is ' + bV ZMW/w
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + kF/9-[]$g,
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' FJ asS8
FROM sysfiles &hRvol\J
WHERE name = @LogicalFileName .A6(D$O k
DROP TABLE DummyTrans J~#;<e{\"
SET NOCOUNT OFF D1__n6g[
8、说明:更改某个表 N^3N[lD{
exec sp_changeobjectowner 'tablename','dbo' lsJnI|
9、存储更改全部表 !?|Th5e
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ANgw"&&>(
@OldOwner as NVARCHAR(128), 9W(dmde>
@NewOwner as NVARCHAR(128) 1Tu
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AS O%FPS=
DECLARE @Name as NVARCHAR(128) S#+h$UVh
DECLARE @Owner as NVARCHAR(128) Th=eNL]
DECLARE @OwnerName as NVARCHAR(128) lV%N
DECLARE curObject CURSOR FOR L'u\w
select 'Name' = name, @|\}.M<e*)
'Owner' = user_name(uid) jYe'V#5S#
from sysobjects U"Zmv
where user_name(uid)=@OldOwner )I3NeKWz
order by name o<N nV
OPEN curObject EVoEszR
FETCH NEXT FROM curObject INTO @Name, @Owner /iX+ R@
WHILE(@@FETCH_STATUS=0) tg{H9tU;
BEGIN
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if @Owner=@OldOwner u9N 1pZ~
begin D:erBMKv,
set @OwnerName = @OldOwner + '.' + rtrim(@Name) nw-I|PVTNa
exec sp_changeobjectowner @OwnerName, @NewOwner ]C) 4
end ?mwD*LN3o
-- select @name,@NewOwner,@OldOwner 92EWIHEWZ
FETCH NEXT FROM curObject INTO @Name, @Owner Z?\2F%
END }mAa}{_
close curObject ~$~5qwl
deallocate curObject p\<u6v ~J
GO %"P,1&\^
10、SQL SERVER中直接循环写入数据 }K&7%N4LZ
declare @i int kXf'5p1
set @i=1 1PpyV f
while @i<30 78/Zk}I]
begin 9]@A]p!
insert into test (userid) values(@i) d+'p@!W_
set @i=@i+1 ariLG [:X
end @7B$Yy#
小记存储过程中经常用到的本周,本月,本年函数 .C--gQpIv
Dateadd(wk,datediff(wk,0,getdate()),-1) (;q;E\Ejq
Dateadd(wk,datediff(wk,0,getdate()),6) rYbpih=x
Dateadd(mm,datediff(mm,0,getdate()),0) ({q?d[q[
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0))
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Dateadd(yy,datediff(yy,0,getdate()),0) E160A5BTx
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) g[3)P+
上面的SQL代码只是一个时间段 <TP=oq?I/
Dateadd(wk,datediff(wk,0,getdate()),-1) l6d$V9A
Dateadd(wk,datediff(wk,0,getdate()),6) )'~6HO8Z
就是表示本周时间段. ={z*akn,
下面的SQL的条件部分,就是查询时间段在本周范围内的: $g
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) {HCzp,Y
而在存储过程中 Rp5#clsy
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) |]c8jG\h
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) DK$s&zf