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。 %d0S-.
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一、基础 {{3H\
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1、说明:创建数据库 S7a6ntei
CREATE DATABASE database-name g8+,wSE
2、说明:删除数据库 zb/Xfu.)?6
drop database dbname @(c<av?
3、说明:备份sql server @S7=6RKa[
--- 创建 备份数据的 device H040-Q;S'
USE master =BS'oBn^6
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' XQOprIJ
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--- 开始 备份 SSLshY~d
BACKUP DATABASE pubs TO testBack udGGDH
4、说明:创建新表 zt2-w/[Q
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) } qv-lO
根据已有的表创建新表: XyphQ}\u
A:create table tab_new like tab_old (使用旧表创建新表) E ZKz-}
B:create table tab_new as select col1,col2... from tab_old definition only ? SP7vQ/
5、说明:删除新表 9Nu#&_2R
drop table tabname ~{YgM/c|dt
6、说明:增加一个列 xD#I&.
Alter table tabname add column col type o'7ju~0L
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。 AtlR!IEUb
7、说明:添加主键: Alter table tabname add primary key(col)
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说明:删除主键: Alter table tabname drop primary key(col) 9yo[T(8
8、说明:创建索引:create [unique] index idxname on tabname(col....) %`QsX {?,
删除索引:drop index idxname ;lH,bX~5
注:索引是不可更改的,想更改必须删除重新建。 eH
9、说明:创建视图:create view viewname as select statement T(UYlLe
删除视图:drop view viewname [|n-x3h
10、说明:几个简单的基本的sql语句 a<'$` z|s
选择:select * from table1 where 范围 -0SuREn
插入:insert into table1(field1,field2) values(value1,value2) $pfe2(8
删除:delete from table1 where 范围 $D s]\j*
更新:update table1 set field1=value1 where 范围 8.Ef 5-m
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ?gwbg*
排序:select * from table1 order by field1,field2 [desc] m=\eL~h
总数:select count as totalcount from table1 ev%t5NZ
求和:select sum(field1) as sumvalue from table1 MD4 j~q\g
平均:select avg(field1) as avgvalue from table1 1IQOl
最大:select max(field1) as maxvalue from table1 rg^\BUa-W,
最小:select min(field1) as minvalue from table1 z%3"d0
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11、说明:几个高级查询运算词 yr9A0F0
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A: UNION 运算符 Zmbz-##HQ
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 qV8\/7'A0a
B: EXCEPT 运算符 Ym{%"EB
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 gpK_0?%
C: INTERSECT 运算符 C.)&FW2F_
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 Bb[e[,ah
注:使用运算词的几个查询结果行必须是一致的。 gDNTIOV
12、说明:使用外连接 _K}_h\e.
A、left outer join: 5m USh3
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 ^xw [d}0S
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c
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B:right outer join: Gx_`|I{P
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 x";.gjI |g
C:full outer join: R^M (fC
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 \1`DaQp7
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二、提升 ^$+f3Z'
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) B%rr}Ro1e
法一:select * into b from a where 1<>1 7R<u=U
法二:select top 0 * into b from a Ed&,[rC
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) m)|.:sj
insert into b(a, b, c) select d,e,f from b; ZYR,8 y
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) aQ&8fteFR
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 lDPRn~[#\
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. hW!@$Ph
4、说明:子查询(表名1:a 表名2:b) }Q r0T
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) 2}`V c{\
5、说明:显示文章、提交人和最后回复时间 aU.0dsq
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b zNr_W[
6、说明:外连接查询(表名1:a 表名2:b) 76_8e{zbr
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c }RN=9J
7、说明:在线视图查询(表名1:a ) MZMS?}.2
select * from (SELECT a,b,c FROM a) T where t.a > 1; N 1f~K.e\
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 .H(}[eG_
select * from table1 where time between time1 and time2 N<Z)b!o%u
select a,b,c, from table1 where a not between 数值1 and 数值2 7{+Io
9、说明:in 的使用方法 _
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select * from table1 where a [not] in ('值1','值2','值4','值6') 9Ajgfy>
10、说明:两张关联表,删除主表中已经在副表中没有的信息 _/%]:
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) F{*9[jY
11、说明:四表联查问题: 9HNh*Gc=
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... fyg~KF}
12、说明:日程安排提前五分钟提醒 &pMlt7
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ??zABV
13、说明:一条sql 语句搞定数据库分页 )-9w3W1r
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 mam5G!$
14、说明:前10条记录 *Nf4bH%MN
select top 10 * form table1 where 范围 4&]To@>
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.) z)W#&JFF
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) -4y)qGb*?
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 'tV"^KQHI
(select a from tableA ) except (select a from tableB) except (select a from tableC) iZ.&q
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17、说明:随机取出10条数据 kf^-m/
select top 10 * from tablename order by newid() |Y8Mk2,s
18、说明:随机选择记录 0'%+X|
select newid() cfC; eRgq~
19、说明:删除重复记录 g3|Y$/J7P
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 7<QYT+6xV
20、说明:列出数据库里所有的表名 HzG~I8o(d
select name from sysobjects where type='U' qD$GKN.
21、说明:列出表里的所有的 t.>te'DK/
select name from syscolumns where id=object_id('TableName') n$m]58w
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 {*<O"|v
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type @wB'3q}(
显示结果: d)hzi
type vender pcs 6Y>,e;R
电脑 A 1 y\|-O<8O
电脑 A 1 lNA'M&
光盘 B 2 3<jAp#bE
光盘 A 2 1fO2)$Y
手机 B 3 fUp|3bBE
手机 C 3 }/7.+yD
23、说明:初始化表table1 CFkW@\]
TRUNCATE TABLE table1 fbHWBb
24、说明:选择从10到15的记录 %7C%`)T]
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc nv_m!JG7
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三、技巧 8tT&BmT
1、1=1,1=2的使用,在SQL语句组合时用的较多 2sd ) w
"where 1=1" 是表示选择全部 "where 1=2"全部不选, s.p1L
如: k}I5x1>&
if @strWhere !='' mI?* Z%>g
begin 7}#*3*]
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere '.%iPMM
end W>q*.9}Y"
else 5I)~4.U|,m
begin ~ F?G5cN5
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' t-eKruj+
end _#J_$CE#
我们可以直接写成 P^K?E
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere "LP,
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2、收缩数据库 1IOo?e=/bM
--重建索引 QLF,/"
DBCC REINDEX 2<y}91N:
DBCC INDEXDEFRAG +K$5tT6b
--收缩数据和日志 XQ0#0<
DBCC SHRINKDB u5cVz_S
DBCC SHRINKFILE W2F+^
3、压缩数据库 Nh1e1m?
dbcc shrinkdatabase(dbname) 0okO+QU,a
4、转移数据库给新用户以已存在用户权限 zt)p`kd D
exec sp_change_users_login 'update_one','newname','oldname' L)kb (TH
go teq^xTUF[
5、检查备份集 cotxo?)Zv
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' o;M.Rt\A
6、修复数据库 |n|U;|'^
ALTER DATABASE [dvbbs] SET SINGLE_USER -!'Oy%a#
GO gtaV6sD
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Qm35{^p+
GO 097Fvt=#
ALTER DATABASE [dvbbs] SET MULTI_USER #L@} .Giz
GO JAGi""3HG
7、日志清除 1AV1d%F
SET NOCOUNT ON [ 5CS}FB
DECLARE @LogicalFileName sysname, :"OZc7
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@MaxMinutes INT, _KSfP7VU
@NewSize INT A6?qIy
USE tablename -- 要操作的数据库名 BB2_J=wA
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 njy~
@MaxMinutes = 10, -- Limit on time allowed to wrap log. >zPO>.?h7T
@NewSize = 1 -- 你想设定的日志文件的大小(M)
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-- Setup / initialize TRs[ ~K)n
DECLARE @OriginalSize int LPq*ZZK
SELECT @OriginalSize = size VZT6;1TD$8
FROM sysfiles 1&X}1
WHERE name = @LogicalFileName 3o+KP[A
SELECT 'Original Size of ' + db_name() + ' LOG is ' + kP!%|&w;
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Tm%$J
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' fs2mN1
FROM sysfiles Qa,NGP.
WHERE name = @LogicalFileName itqQ)\W
CREATE TABLE DummyTrans GN:Ru|n
(DummyColumn char (8000) not null) s
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DECLARE @Counter INT, S+.21,
@StartTime DATETIME, ri/t(m^{W
@TruncLog VARCHAR(255) w8AJ#9W
SELECT @StartTime = GETDATE(), ! 6p>P4TT
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' o|z+!,
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ^?$D.^g
EXEC (@TruncLog) \]Y\P~n
-- Wrap the log if necessary. l 8O"w&
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired E/"YId `A
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ~pHJ0g:t
AND (@OriginalSize * 8 /1024) > @NewSize h|J;6Sm@
BEGIN -- Outer loop. ]4Nvh\/P9
SELECT @Counter = 0 a~8:rW^
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) /_NkB$&
BEGIN -- update fkdf~Vb
INSERT DummyTrans VALUES ('Fill Log') BKa A=Bl
DELETE DummyTrans -vyIOH,
SELECT @Counter = @Counter + 1 G*kE~s9R
END 07.nq;/R
EXEC (@TruncLog) 6@"Vqm|HD
END @IEI%vH
SELECT 'Final Size of ' + db_name() + ' LOG is ' + >|l;*Kw,/P
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + X4d Xm>*?=
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' gbY LA a
FROM sysfiles >]>0KQfO
WHERE name = @LogicalFileName D3<IuWeM
DROP TABLE DummyTrans >}ro[x`K
SET NOCOUNT OFF <T(s\N5B=
8、说明:更改某个表 =}~NRmmF
exec sp_changeobjectowner 'tablename','dbo' I["F+kt^^
9、存储更改全部表 [:AB$l*
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 5Z*
b(R
@OldOwner as NVARCHAR(128), T&o,I
@NewOwner as NVARCHAR(128) m(2G*}
AS \w{@u)h
DECLARE @Name as NVARCHAR(128) fUb1/-}
DECLARE @Owner as NVARCHAR(128) ,]0S4h67
DECLARE @OwnerName as NVARCHAR(128) JaH*
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DECLARE curObject CURSOR FOR l_^T&xq8
select 'Name' = name, Oamv9RyDvC
'Owner' = user_name(uid) Kg4QT/0VA
from sysobjects zt7_r`#z
where user_name(uid)=@OldOwner ]O6KKz
order by name ^{),+S
OPEN curObject nVz5V%a!\q
FETCH NEXT FROM curObject INTO @Name, @Owner uQeqnGp
WHILE(@@FETCH_STATUS=0) m,\i
BEGIN fp9rO}##
if @Owner=@OldOwner IM@"AD52a
begin
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) U5|B9%:&
exec sp_changeobjectowner @OwnerName, @NewOwner G1kDM.L
end l<u{6o
-- select @name,@NewOwner,@OldOwner x}v1X`6b
FETCH NEXT FROM curObject INTO @Name, @Owner &J\B\`
END 3Z_t%J5QZ$
close curObject [_j6cj]
deallocate curObject :9(3h"
GO 6,B-:{{e"
10、SQL SERVER中直接循环写入数据 ?lF mXZy`
declare @i int 0('OyH)
set @i=1 aL88E
while @i<30 \s,Iz[0Vfz
begin f_oq1 W)9
insert into test (userid) values(@i) 3}08RU7[!
set @i=@i+1 )\8URc|J
end yPSVwe|g
小记存储过程中经常用到的本周,本月,本年函数 66/Z\H^d
Dateadd(wk,datediff(wk,0,getdate()),-1) E^7C
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Dateadd(wk,datediff(wk,0,getdate()),6) DP|TIt ,Rl
Dateadd(mm,datediff(mm,0,getdate()),0) "]v
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) I%SuT7"Do
Dateadd(yy,datediff(yy,0,getdate()),0) PoJmW^:}
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) `tX@8|
上面的SQL代码只是一个时间段 3voW
Dateadd(wk,datediff(wk,0,getdate()),-1) q5%2WM]6
Dateadd(wk,datediff(wk,0,getdate()),6) z9^c]U U)E
就是表示本周时间段. Cy`26[E$S
下面的SQL的条件部分,就是查询时间段在本周范围内的: <'W=]IAV
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ldK>HxM%Z
而在存储过程中 ,g%o
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) >J.Qm0TY(
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) <F ew<r2