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。 b}NNkM
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一、基础 f@YdL6&d-
1、说明:创建数据库 U)f('zD
CREATE DATABASE database-name nxhlTf>3
2、说明:删除数据库 z<9C-
drop database dbname M7?ktK9`ma
3、说明:备份sql server ORrZu$n`p
--- 创建 备份数据的 device *7H
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USE master V5$Gb6?K
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 'dBe,@
--- 开始 备份 ?WXftzdf6u
BACKUP DATABASE pubs TO testBack AJ6l#j-
4、说明:创建新表 OF`J{`{r
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) rK'Lvt@w
根据已有的表创建新表: ;MNUT,U
A:create table tab_new like tab_old (使用旧表创建新表) n[e C
B:create table tab_new as select col1,col2... from tab_old definition only .n8O 3V
5、说明:删除新表 7~+Fec`Ut*
drop table tabname Pl/Xh03E
6、说明:增加一个列 $\*Z
Alter table tabname add column col type v#{Nh8n
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。 }=v4(M `%
7、说明:添加主键: Alter table tabname add primary key(col) ox`Zs2-a
说明:删除主键: Alter table tabname drop primary key(col) eik_w(xPT
8、说明:创建索引:create [unique] index idxname on tabname(col....) >3D1:0Sg
删除索引:drop index idxname er24}G8
注:索引是不可更改的,想更改必须删除重新建。 oS$7k3s
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9、说明:创建视图:create view viewname as select statement *#>(P
删除视图:drop view viewname 9d|8c >
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10、说明:几个简单的基本的sql语句 v`QDms,{
选择:select * from table1 where 范围 # *pB"L
插入:insert into table1(field1,field2) values(value1,value2) vdn)+fZ;
删除:delete from table1 where 范围 n\D/WLv M
更新:update table1 set field1=value1 where 范围 sXEIC#rq
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 0cKsGDm
排序:select * from table1 order by field1,field2 [desc] )t+pwh!8
总数:select count as totalcount from table1 +o4o!;E)
求和:select sum(field1) as sumvalue from table1 mD7NQ2:wA
平均:select avg(field1) as avgvalue from table1 Epp>L.?r
最大:select max(field1) as maxvalue from table1
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最小:select min(field1) as minvalue from table1 FVl,
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11、说明:几个高级查询运算词 aNKw.S>
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A: UNION 运算符 Z?xaXFm_
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 =7TWzUCO#
B: EXCEPT 运算符 X\!q8KEpR&
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。
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C: INTERSECT 运算符 Hk+44
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 r6\g#}
注:使用运算词的几个查询结果行必须是一致的。 gzi=+oJ|4
12、说明:使用外连接 }2 S!;swg+
A、left outer join: yB7si(,1>
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 eD7\ ,}O
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 2X' H^t]7
B:right outer join: 8*&-u +@%
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 /Z*$k{qIR&
C:full outer join: !lzj.|7=1
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。 SE(<(w
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二、提升 >DY/CcG\P
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 4d@0v n{
法一:select * into b from a where 1<>1 ?z M
法二:select top 0 * into b from a chD7^&5]
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 0P$19TN
insert into b(a, b, c) select d,e,f from b; +Q_xY>ej
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) $#e}9g.
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 !-qk1+<h
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. jS3@Z?x?*
4、说明:子查询(表名1:a 表名2:b) =>Ae]mi7
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) B YB9M
5、说明:显示文章、提交人和最后回复时间 IuPDr %
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b !^L}LtqHI
6、说明:外连接查询(表名1:a 表名2:b) *tZ3?X[b
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c mhIGunK;+
7、说明:在线视图查询(表名1:a ) N0lFx?4
select * from (SELECT a,b,c FROM a) T where t.a > 1; H"pYj
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 _`QME r?
select * from table1 where time between time1 and time2 Th,]nVsGs~
select a,b,c, from table1 where a not between 数值1 and 数值2 >@4Ds"Ye"O
9、说明:in 的使用方法 W{ozZuo
select * from table1 where a [not] in ('值1','值2','值4','值6') hHw1<! M
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ZPM7R3%V)z
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) \K9Y@jnr
11、说明:四表联查问题: cQh{z8Bf?<
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... 6"?#s/fk
12、说明:日程安排提前五分钟提醒 Q!~1Xc0S`p
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 /mE:2K]C
13、说明:一条sql 语句搞定数据库分页 PK?}hz
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 {Q K9pZB
14、说明:前10条记录 .*EP$pc
select top 10 * form table1 where 范围 .*FlB>1jy
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.) FGwgSrXL7
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) t?uw^nV 3E
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 6*ZZ)W<
(select a from tableA ) except (select a from tableB) except (select a from tableC) ,h3,&,
17、说明:随机取出10条数据 Qw%0<~<
select top 10 * from tablename order by newid() T^xp2cZ
18、说明:随机选择记录 8v;T_VN
select newid() OZObx
19、说明:删除重复记录 "J
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) wL0"1Ya
20、说明:列出数据库里所有的表名 !})3Fb
select name from sysobjects where type='U' U/(R_U>=
21、说明:列出表里的所有的 a~tBg y+9
select name from syscolumns where id=object_id('TableName') 4f0dc\$
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。 Xw^:<Nx:
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 9*|An
显示结果: [iSLn3XXRX
type vender pcs e8]mdU{)
电脑 A 1 S
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电脑 A 1 x2f_>tu2
光盘 B 2 V|0UwS\n
光盘 A 2 ]}0+7Q
手机 B 3 yFP#z5G
手机 C 3
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23、说明:初始化表table1 s3T 6"%S`
TRUNCATE TABLE table1 :\1&5Pm]
24、说明:选择从10到15的记录 bL7mlh
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc X_|} b[b
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三、技巧 ?Z7C0u#wd
1、1=1,1=2的使用,在SQL语句组合时用的较多 qm}7w3I^
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 8|Y^z_C
如: *XzUqK
if @strWhere !='' I`KN8ll
begin }#u}{
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere q+G1#5
end ||,;07
else -)<Nd:A
begin o_$r*Z|HG
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' !p9F'7;Y<
end qx? lCz a"
我们可以直接写成 QU4'x4YS
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Ip1QmP
2、收缩数据库 j+ys&pDczm
--重建索引 Y2D)$
DBCC REINDEX Em.?
DBCC INDEXDEFRAG Ul@'z|
--收缩数据和日志 K|1^?#n
DBCC SHRINKDB V+K.'
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DBCC SHRINKFILE ,zyrBO0 Eq
3、压缩数据库 0UB'6wRVo
dbcc shrinkdatabase(dbname) n<$I, IRE
4、转移数据库给新用户以已存在用户权限 "7
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exec sp_change_users_login 'update_one','newname','oldname' t[
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go 5Q'R5]?h
5、检查备份集 1Q$ M/}
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' _1JvA-
6、修复数据库 ! O>mu6:Rf
ALTER DATABASE [dvbbs] SET SINGLE_USER @<sP1`1
GO +%~g$#tlJo
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK tr} $82Po
GO sR0nY8@F
ALTER DATABASE [dvbbs] SET MULTI_USER Stw6%T-
GO U5PCj ]-Xt
7、日志清除 v>P){VT
SET NOCOUNT ON Y+7v~/K=
DECLARE @LogicalFileName sysname, 0nd<6S+fs
@MaxMinutes INT, / L8=8
@NewSize INT t8[:}[Jx
USE tablename -- 要操作的数据库名 0&-sz=L
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 2g v(`NKYE
@MaxMinutes = 10, -- Limit on time allowed to wrap log. M;bQid@BG
@NewSize = 1 -- 你想设定的日志文件的大小(M) <Jk|Bmw;
-- Setup / initialize }?^G=IP4(
DECLARE @OriginalSize int _8>"&1n
SELECT @OriginalSize = size tpctz~ .
FROM sysfiles y%y#Pb|
WHERE name = @LogicalFileName G7<X l}
SELECT 'Original Size of ' + db_name() + ' LOG is ' + PrcM'Q
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + "869n37
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' dd+).*
FROM sysfiles &Hqu`A/^
WHERE name = @LogicalFileName m}E$6E^~O
CREATE TABLE DummyTrans \CGcP
(DummyColumn char (8000) not null) !]nCeo
DECLARE @Counter INT, }R x%&29&
@StartTime DATETIME, `xr%LsNn
@TruncLog VARCHAR(255) }ie]7N6;
SELECT @StartTime = GETDATE(), .wSAysiQ|P
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ]gW J,
DBCC SHRINKFILE (@LogicalFileName, @NewSize) qG qu/$bh
EXEC (@TruncLog) SOL=3hfb^
-- Wrap the log if necessary. |<0@RCgM
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired +*q@= P,
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ]lY9[~
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AND (@OriginalSize * 8 /1024) > @NewSize *Y ZLQT
BEGIN -- Outer loop. DPOPRi~
SELECT @Counter = 0 v=>Gvl3&U
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) -Me\nu8(RF
BEGIN -- update C(t/:?(y
INSERT DummyTrans VALUES ('Fill Log') (Wqhuw!u
DELETE DummyTrans LayU)TIt
SELECT @Counter = @Counter + 1 S8VR#
END nz\fN?q
EXEC (@TruncLog) xTMTkVa+B
END }t'^Au`X
SELECT 'Final Size of ' + db_name() + ' LOG is ' + U:9vjY
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + !Xi>{nV
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' F{,O+\
FROM sysfiles 8.':pY'8"
WHERE name = @LogicalFileName (/U1J
DROP TABLE DummyTrans Hi9z<l=$
SET NOCOUNT OFF z<>_*Lfj
8、说明:更改某个表 rE:>G]j6
exec sp_changeobjectowner 'tablename','dbo' "_j7kYAl
9、存储更改全部表 `uHpj`EU
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch f,>i%.
@OldOwner as NVARCHAR(128), o=QF>\\
@NewOwner as NVARCHAR(128) Pa +BE[z
AS :F=nb+HZ
DECLARE @Name as NVARCHAR(128) _4$DnQ6&
DECLARE @Owner as NVARCHAR(128) vM/v}6;_K2
DECLARE @OwnerName as NVARCHAR(128) ".?{Y(~
DECLARE curObject CURSOR FOR H@'
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select 'Name' = name, #7h fEAk
'Owner' = user_name(uid) XD }_9p
from sysobjects w>_EM&r6~u
where user_name(uid)=@OldOwner em}Qv3*#
order by name {2^@jD
OPEN curObject {2r7:nvR
FETCH NEXT FROM curObject INTO @Name, @Owner ^6>|!
WHILE(@@FETCH_STATUS=0) .`N`M9
BEGIN Els= :4
if @Owner=@OldOwner {C6;$#7P
begin @0,dyg<$>
set @OwnerName = @OldOwner + '.' + rtrim(@Name) z&,sm5Lb
exec sp_changeobjectowner @OwnerName, @NewOwner l0if#?4\r
end $:II@=
-- select @name,@NewOwner,@OldOwner 7,UFIHq
FETCH NEXT FROM curObject INTO @Name, @Owner PSS/JFZ^
END '/g+;^_cB
close curObject @(fY4]K
deallocate curObject bGc|SF<V
GO e~]e9-L>I
10、SQL SERVER中直接循环写入数据 $i~`vu*
declare @i int 9mphj)`d;#
set @i=1 fcXk]W
while @i<30 arVf"3a
begin S@NhEc
insert into test (userid) values(@i) hpV
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set @i=@i+1 =3dbw8I
end jYID44$
小记存储过程中经常用到的本周,本月,本年函数 _J~ta.
Dateadd(wk,datediff(wk,0,getdate()),-1) 7Sq{A@ET
Dateadd(wk,datediff(wk,0,getdate()),6) {0WIDD
Dateadd(mm,datediff(mm,0,getdate()),0) ]f-'A>MC
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 4 ~YQ\4h=
Dateadd(yy,datediff(yy,0,getdate()),0) 9~%]|_(
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) )h_7 2
上面的SQL代码只是一个时间段 X]U"ru{1q
Dateadd(wk,datediff(wk,0,getdate()),-1) edk9Qd9
Dateadd(wk,datediff(wk,0,getdate()),6) | O+>#
就是表示本周时间段. {)9HS~e T
下面的SQL的条件部分,就是查询时间段在本周范围内的: %aE7id>v6
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) !_H8Q}a
而在存储过程中 <&EO=A
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) UJ)M:~O
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) pjs9b%.