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。 _5<d'fBd
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一、基础 _v~c3y).
1、说明:创建数据库 bv %Bo4s
CREATE DATABASE database-name -D=J/5L#5
2、说明:删除数据库 G]Rb{v,r
drop database dbname Po(Y',xI[
3、说明:备份sql server ?D 8<}~Do
--- 创建 备份数据的 device Ew`(x30E
USE master r~mZ?dI
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' R]dN-'U
--- 开始 备份 N.\?"n
BACKUP DATABASE pubs TO testBack jb0wP01R
4、说明:创建新表 e6?iQ0
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) K1`Z}k_p.
根据已有的表创建新表: *\#/4_yB}
A:create table tab_new like tab_old (使用旧表创建新表) -cDS+*[
B:create table tab_new as select col1,col2... from tab_old definition only z{wW6sgPr
5、说明:删除新表 .h({ P#QT
drop table tabname Uc>kiWW
6、说明:增加一个列 Ej_ >*^b
Alter table tabname add column col type k2bjBAT
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。 6JrwPZB
7、说明:添加主键: Alter table tabname add primary key(col) n ~c<[
说明:删除主键: Alter table tabname drop primary key(col) @;\2 PD
8、说明:创建索引:create [unique] index idxname on tabname(col....) U-F\3a;&
删除索引:drop index idxname }%8 :8_Ke
注:索引是不可更改的,想更改必须删除重新建。 Lzr&Q(mL
9、说明:创建视图:create view viewname as select statement `'W/uCpl
删除视图:drop view viewname F747K);_
10、说明:几个简单的基本的sql语句 ?<F=*eS
选择:select * from table1 where 范围 }-Ds%L
插入:insert into table1(field1,field2) values(value1,value2) ,=_)tX^
删除:delete from table1 where 范围 7Shau%2C
更新:update table1 set field1=value1 where 范围 %
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! |Do+=Gr$t@
排序:select * from table1 order by field1,field2 [desc] 3!l+)g
总数:select count as totalcount from table1 &7\=Jw7w
求和:select sum(field1) as sumvalue from table1
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平均:select avg(field1) as avgvalue from table1 ddTsR
最大:select max(field1) as maxvalue from table1 Q,ezAE
最小:select min(field1) as minvalue from table1 ^`~s#L7
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11、说明:几个高级查询运算词 y ;/T.W9!
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A: UNION 运算符 7$"A2x
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。 "*U0xnI
B: EXCEPT 运算符 hqXp>.W
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。 Ie<H4G5Vh
C: INTERSECT 运算符 %`EyG
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。 `e`}dgf0S|
注:使用运算词的几个查询结果行必须是一致的。 ^l:~r2
12、说明:使用外连接 I`~Giz7@
A、left outer join: 1+F0$<e}
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 qnu<"$
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 Z bW!c1s{
B:right outer join: /3`yaYkSh
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。 z|F38(%JJN
C:full outer join: ~|lEi1|
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$.Zg=
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二、提升 NR>&1aRbyb
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) P5JE = &M
法一:select * into b from a where 1<>1 _4f=\
法二:select top 0 * into b from a Bq5-L}z
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) \y(ZeNs
insert into b(a, b, c) select d,e,f from b; *V`E)maU
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) XtZeT~/7RT
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 qEvbKy}
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. >vR7l&"
4、说明:子查询(表名1:a 表名2:b) S`Xx('!/|
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) }Ug O$1
5、说明:显示文章、提交人和最后回复时间 A-eRL`
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b @CtnV|
6、说明:外连接查询(表名1:a 表名2:b) &s(mbpV
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c c(kYCVc
7、说明:在线视图查询(表名1:a ) 8 7z]qE
select * from (SELECT a,b,c FROM a) T where t.a > 1; b}3t8?wG&
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 kt#t-N;}x
select * from table1 where time between time1 and time2 8U%y[2sT
select a,b,c, from table1 where a not between 数值1 and 数值2 S"cim\9xP
9、说明:in 的使用方法 Ihd{tmr<
select * from table1 where a [not] in ('值1','值2','值4','值6') S l`F`
10、说明:两张关联表,删除主表中已经在副表中没有的信息 [ KDNKK
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Hmx
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11、说明:四表联查问题: =E$B0^_2RC
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 ..... -l~+cI \2
12、说明:日程安排提前五分钟提醒 NI:3hfs
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 *7w,o?l
13、说明:一条sql 语句搞定数据库分页 6zp]SPY
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 ,_UTeW6M
14、说明:前10条记录 ;lQ>>[*
select top 10 * form table1 where 范围 )zydD=,bu
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.) \>tx:;D3
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b)
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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 KTE X]
(select a from tableA ) except (select a from tableB) except (select a from tableC) V6bjVd9|Z
17、说明:随机取出10条数据 >rYkVlv
select top 10 * from tablename order by newid() [VE>{4]W
18、说明:随机选择记录 T<%%f.x[s
select newid() yf2P6b\
19、说明:删除重复记录 tH(g;flO)
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ,YBe|3
20、说明:列出数据库里所有的表名 _l+8[\v
select name from sysobjects where type='U' %l3f .
21、说明:列出表里的所有的 b(Yxsy{U
select name from syscolumns where id=object_id('TableName') ]m :Y|,:6
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。 d/[kky}
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 i~LY
显示结果: $=5kn>[_Z%
type vender pcs e0M'\'J
电脑 A 1 `|<? sjY
电脑 A 1 d5"rCd[
光盘 B 2 oL7F^34;
光盘 A 2 (sSGJS'X
手机 B 3 FY)US>
手机 C 3 X4JSI%E
23、说明:初始化表table1 t[ZGY,8
TRUNCATE TABLE table1 tC5>K9Ed
24、说明:选择从10到15的记录 eVzZfB-=4}
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Y[s}?Xu]w#
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三、技巧 P9x':I$
1、1=1,1=2的使用,在SQL语句组合时用的较多 v\+`n^=
"where 1=1" 是表示选择全部 "where 1=2"全部不选, r)Ja\;
如: Y(Y#H$w
if @strWhere !='' ]QQeUxi
begin FzAzAl5
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ,F n-SrB:
end o%OwKp
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else PU4-}!K
begin _:%i6c*"
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' aK8s0G!z?5
end (o^?i2)g
我们可以直接写成 2|&SG3e+(I
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ZcN#jnb0/
2、收缩数据库 2$'bOo
--重建索引 {$V2L4
DBCC REINDEX R+El/ya:6
DBCC INDEXDEFRAG [{:
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--收缩数据和日志 qCB{dp/
DBCC SHRINKDB vSY
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DBCC SHRINKFILE g""Ep
3、压缩数据库 B}J0d
dbcc shrinkdatabase(dbname) V{fG~19
4、转移数据库给新用户以已存在用户权限 yG;@S8zC
exec sp_change_users_login 'update_one','newname','oldname' I]%Kd('
go 0es\
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5、检查备份集 j9X|c7|
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' vnS8N
6、修复数据库 6ld /E
ALTER DATABASE [dvbbs] SET SINGLE_USER j.[W] EfL~
GO /6Kx249Dw
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 7.]H9
GO P26"z))~d
ALTER DATABASE [dvbbs] SET MULTI_USER tO?-@Qf/9<
GO HQnc`2
7、日志清除 @)wsHW%cjz
SET NOCOUNT ON q8H nPXV
DECLARE @LogicalFileName sysname, d5`D[,]d
@MaxMinutes INT, S|fb'
@NewSize INT =&<d4'(Qk
USE tablename -- 要操作的数据库名 h"[:$~/UJ
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 7GCxd#DJ
@MaxMinutes = 10, -- Limit on time allowed to wrap log. '2UQN7@d
@NewSize = 1 -- 你想设定的日志文件的大小(M) >hzSd@J&
-- Setup / initialize 7*
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DECLARE @OriginalSize int RRQIlI<
SELECT @OriginalSize = size 8c>xgFWp9
FROM sysfiles qFl|q0\ A
WHERE name = @LogicalFileName 5#y_EpL"
SELECT 'Original Size of ' + db_name() + ' LOG is ' + y;(G%s1
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + <AK9HPxP
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' >x6)AH.
FROM sysfiles 5tk7H2K^<
WHERE name = @LogicalFileName *!j!o%MB
CREATE TABLE DummyTrans J/3$I
(DummyColumn char (8000) not null) skU
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DECLARE @Counter INT, ]u:_r)T
@StartTime DATETIME, C=IN "
@TruncLog VARCHAR(255) nPDoK!r'
SELECT @StartTime = GETDATE(), +~= j3U
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 4P"XT
DBCC SHRINKFILE (@LogicalFileName, @NewSize) itg"dGDk
EXEC (@TruncLog) 0g~Cdp
-- Wrap the log if necessary. 3E0C$vKM
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired rHuzGSX54
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) U$S{j&?
AND (@OriginalSize * 8 /1024) > @NewSize Q#*R({)GH
BEGIN -- Outer loop. L$rr:^J
SELECT @Counter = 0 =pTTXo
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) jp1e3 Cg
BEGIN -- update dpX Fx"4A
INSERT DummyTrans VALUES ('Fill Log') y7R=zkd
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DELETE DummyTrans !Rgj'{
SELECT @Counter = @Counter + 1 [)kuu
END 4Xww(5?3
EXEC (@TruncLog) `m#i|8
END gf>GK/^HH
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ]h=5d09z
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + zbGZ\pz
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ;),,Hk
FROM sysfiles 6urU[t1
WHERE name = @LogicalFileName jc\y{ I\
DROP TABLE DummyTrans )o-mM
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SET NOCOUNT OFF 9MQjSNYzo
8、说明:更改某个表 O1wo
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exec sp_changeobjectowner 'tablename','dbo' Do5.
9、存储更改全部表 Y9&na&vY?
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch x34GRe!!
@OldOwner as NVARCHAR(128), B|8|f(tsSa
@NewOwner as NVARCHAR(128) HLdHyK/S
AS iq^;c syKb
DECLARE @Name as NVARCHAR(128) atmW? Z
DECLARE @Owner as NVARCHAR(128) SoHaGQox
DECLARE @OwnerName as NVARCHAR(128) $DtUTh3)
DECLARE curObject CURSOR FOR YU!s;h
select 'Name' = name, -yTIv*y
'Owner' = user_name(uid) ,oPxt
from sysobjects da_0{;wR
where user_name(uid)=@OldOwner @; I9e
order by name 9\T9pjdZE
OPEN curObject M4CC&?6\
FETCH NEXT FROM curObject INTO @Name, @Owner SU6Aq?`@
WHILE(@@FETCH_STATUS=0) TCIbPsE
BEGIN `e?~c'a@
if @Owner=@OldOwner ? STO#<a
begin '#eT
set @OwnerName = @OldOwner + '.' + rtrim(@Name) [tElt4uG
exec sp_changeobjectowner @OwnerName, @NewOwner rkR~%U6V
end Y> ATL
-- select @name,@NewOwner,@OldOwner {,Rlq
FETCH NEXT FROM curObject INTO @Name, @Owner >,I'S2_Zl
END !IB}&m
close curObject '5~l{3Lw
deallocate curObject wO`G_!W9
GO 4x3 _8/=
10、SQL SERVER中直接循环写入数据 N:S2X+}(
declare @i int $|TLt{ K
set @i=1 6Z2|j~
while @i<30 5zkj;?s
begin 53pT{2]zAi
insert into test (userid) values(@i) *!{&n*N
set @i=@i+1 Ap;^\5
end n2Mpo\2
小记存储过程中经常用到的本周,本月,本年函数 pG"hZB3)
Dateadd(wk,datediff(wk,0,getdate()),-1) AZA5>Y
Dateadd(wk,datediff(wk,0,getdate()),6) @$
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Dateadd(mm,datediff(mm,0,getdate()),0) g jzWW0C
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Dhfor+Epy
Dateadd(yy,datediff(yy,0,getdate()),0) q(L.i)w$
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) z"QXPIXPk
上面的SQL代码只是一个时间段 yLK %lP
Dateadd(wk,datediff(wk,0,getdate()),-1) &0 "*.:J9
Dateadd(wk,datediff(wk,0,getdate()),6) nZc6
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就是表示本周时间段. s0/m qZ]s
下面的SQL的条件部分,就是查询时间段在本周范围内的: U>m{B|H
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) -S&9"=v
而在存储过程中 51H6
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select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) _x#y
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) /C5py-I