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。 $h=v;1"
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一、基础 u-V(
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1、说明:创建数据库 _l,-SQgj
CREATE DATABASE database-name mOLz(0
2、说明:删除数据库 -ni@+Dy
drop database dbname j4=\MK
3、说明:备份sql server ;LKYA?=/V
--- 创建 备份数据的 device Y2g%{keo
USE master QNXS.!\P
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ZHoYnp-~z
--- 开始 备份 ,&Zk63V
BACKUP DATABASE pubs TO testBack U2Ky4UFm
4、说明:创建新表 .&>3nu
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) >f|0# *
根据已有的表创建新表: [w+1<ou;j
A:create table tab_new like tab_old (使用旧表创建新表) u{l4O1k/c
B:create table tab_new as select col1,col2... from tab_old definition only UCTc$3
5、说明:删除新表 1$m{)Io2(
drop table tabname 7 VYhRC-
6、说明:增加一个列 UvqnNA
Alter table tabname add column col type ,t'"3<^Jg
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。 6_tl_O7
7、说明:添加主键: Alter table tabname add primary key(col) F2)KAIl
说明:删除主键: Alter table tabname drop primary key(col) qB`%+<)C
8、说明:创建索引:create [unique] index idxname on tabname(col....) -|=)
删除索引:drop index idxname v+<4?]EJ
注:索引是不可更改的,想更改必须删除重新建。 sdgI ,
9、说明:创建视图:create view viewname as select statement bIV9cpW
删除视图:drop view viewname Mdu\ci)lr
10、说明:几个简单的基本的sql语句 ,.<c|5R
选择:select * from table1 where 范围 ?1eu9; q\*
插入:insert into table1(field1,field2) values(value1,value2) r,L`@A=v
删除:delete from table1 where 范围 a
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更新:update table1 set field1=value1 where 范围 7+6I~&x!Lz
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 7WmY:g#s
排序:select * from table1 order by field1,field2 [desc] uY3#,
总数:select count as totalcount from table1 Uqly|FS &n
求和:select sum(field1) as sumvalue from table1 Ms+SJ5Lg
平均:select avg(field1) as avgvalue from table1 Pt6d5EIG
最大:select max(field1) as maxvalue from table1 _,p/2m-Pj
最小:select min(field1) as minvalue from table1 : 'pK
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11、说明:几个高级查询运算词 XuU>.T$] c
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A: UNION 运算符 ?dCJv_w
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 ~BnmAv$m[
B: EXCEPT 运算符 W3R43>$
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。 lJS3*x#H
C: INTERSECT 运算符 A43[i@o
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。 Kc>Rd
注:使用运算词的几个查询结果行必须是一致的。
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12、说明:使用外连接 VArMFP)cz
A、left outer join: )"E1/$*k
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 cf%2A1I2W
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c zYftgH_o
B:right outer join: +)_DaL
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右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 FIQHs"#T
C:full outer join: CXi:?6OG
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 =#&+w[4?&.
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二、提升 ;YBk.}
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 9h6siK(F
法一:select * into b from a where 1<>1 `vf]C'
法二:select top 0 * into b from a aq(i^d
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Kzwe36O;?
insert into b(a, b, c) select d,e,f from b; yv$hIU2X
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) U\[b qw
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 G^/8^Zi
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. )31xl6@
4、说明:子查询(表名1:a 表名2:b) EKmn@S-&P
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) ;iUO1t)^
5、说明:显示文章、提交人和最后回复时间 Go[anf
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ~D/1U)kt
6、说明:外连接查询(表名1:a 表名2:b) b~TTz`HZ
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c A[:(#iR5-E
7、说明:在线视图查询(表名1:a ) fvA167\
select * from (SELECT a,b,c FROM a) T where t.a > 1; pE.TG4
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 W!* P
select * from table1 where time between time1 and time2 ;9vY5CxzC
select a,b,c, from table1 where a not between 数值1 and 数值2 i3$pqNe
9、说明:in 的使用方法 @CC
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select * from table1 where a [not] in ('值1','值2','值4','值6') \e%%ik,<
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ]BmnE#n&
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 )
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11、说明:四表联查问题: SJsbuLxR
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... jRW@$ <mG
12、说明:日程安排提前五分钟提醒 \+C0Rv^^
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 5tY/ d=\k
13、说明:一条sql 语句搞定数据库分页 ^<j
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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 >h(GmR*xM
14、说明:前10条记录 TR'_v[uK3
select top 10 * form table1 where 范围 d"lk"R
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.) :y_]JL;w
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) "R%
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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 xhMAWFg|
(select a from tableA ) except (select a from tableB) except (select a from tableC) o9OCgP`Y
17、说明:随机取出10条数据 X*&Thmee
select top 10 * from tablename order by newid() 9]I{GyH
18、说明:随机选择记录 mCQ:<#
select newid() iD>H{1 h
19、说明:删除重复记录 NpS =_QeNw
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) IPt
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20、说明:列出数据库里所有的表名 (Hs,Tj
select name from sysobjects where type='U' 'GLpSWL+*
21、说明:列出表里的所有的 6Z@T
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select name from syscolumns where id=object_id('TableName') \[wbJ
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 Ghar
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select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type d8p5a
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显示结果: =(v'8?--
type vender pcs zV"'-iP
电脑 A 1 Mh@n>+IR
电脑 A 1 LeNSjxB
光盘 B 2 s Dsq:z
光盘 A 2 7{NH;U t
手机 B 3 d$n<^~Z
手机 C 3 Z!l]v.S
23、说明:初始化表table1 Nema>T]
TRUNCATE TABLE table1 dl3}\o_
24、说明:选择从10到15的记录 n
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Cli:;yi&n
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三、技巧 lLU8eHf\
1、1=1,1=2的使用,在SQL语句组合时用的较多 }!m}?
"where 1=1" 是表示选择全部 "where 1=2"全部不选, S{,|Fa^PPO
如: ?0lz!Nq'S
if @strWhere !='' 9H+Q/Q*-a
begin Iq
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 1*trtb4F
end g3(LDqB'.
else @H}Hjg_>m
begin ? ^`fPH=
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' nt%p@e!,
end Hv%$6,/ *v
我们可以直接写成 V$dhiP
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Epm8S}6K
2、收缩数据库 #IU^(W
--重建索引 pB7^l|\]
DBCC REINDEX =RQI5nHdw
DBCC INDEXDEFRAG $\PU Y8
--收缩数据和日志 \(r$f!`
DBCC SHRINKDB Hk=HO|&<XB
DBCC SHRINKFILE r4b-.>w
3、压缩数据库 S7~HBgS<
dbcc shrinkdatabase(dbname) }eveNPB{5
4、转移数据库给新用户以已存在用户权限 j@{dsS:6
exec sp_change_users_login 'update_one','newname','oldname' .-Dc%ap]
go al7D3J
5、检查备份集 $ k_6
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' @\W-=YKLg
6、修复数据库 NnaO!QW%
ALTER DATABASE [dvbbs] SET SINGLE_USER bc>&Qj2Z7c
GO xT!<x({
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ACpecG
GO QuC_sFP10
ALTER DATABASE [dvbbs] SET MULTI_USER _7dp(R
GO be?Bf^O>
7、日志清除 [*@
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SET NOCOUNT ON eDvh3Y<D
DECLARE @LogicalFileName sysname, 2HF`}H)H
@MaxMinutes INT, Z_[L5B]Gwd
@NewSize INT !-ZY_
USE tablename -- 要操作的数据库名 #er% q:
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ^1_CS*
@MaxMinutes = 10, -- Limit on time allowed to wrap log. [\&2&
@NewSize = 1 -- 你想设定的日志文件的大小(M) nwIj?(8x
-- Setup / initialize {.J<^V
DECLARE @OriginalSize int e&!8UYP
SELECT @OriginalSize = size $xjfW/k?M
FROM sysfiles ]ZNFrpq
WHERE name = @LogicalFileName Q8$;##hzt
SELECT 'Original Size of ' + db_name() + ' LOG is ' + zV(aw~CbZ
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + F_4Et
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' z";(0%
FROM sysfiles W{~ y< `D
WHERE name = @LogicalFileName VmRfnH"
CREATE TABLE DummyTrans 9mjJC
(DummyColumn char (8000) not null) YGRb|P-
DECLARE @Counter INT, q$Ms7` a
@StartTime DATETIME, 0f_A"K
@TruncLog VARCHAR(255) 4t>"-/
SELECT @StartTime = GETDATE(), k$pND,Ws
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' `7[!bCl
DBCC SHRINKFILE (@LogicalFileName, @NewSize) $9:
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EXEC (@TruncLog) ^)C#
-- Wrap the log if necessary. ew]G@66
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 7nP{a"4_
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) eBY/Y6 R
AND (@OriginalSize * 8 /1024) > @NewSize y9w,Su2
BEGIN -- Outer loop. }w8yYI
SELECT @Counter = 0 X8A.ag0Uu
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) c c/nzB
BEGIN -- update [70 5[
INSERT DummyTrans VALUES ('Fill Log')
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DELETE DummyTrans $RU K<JN$6
SELECT @Counter = @Counter + 1 u!
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END +@*>N;$
EXEC (@TruncLog) ]'$:Y
END 0G2Y_A&e**
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Nbv b_
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + J6"GHbsO
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' .tQ(q=#
FROM sysfiles u6| IKZ
WHERE name = @LogicalFileName 4;eD}g
DROP TABLE DummyTrans ,s2C)bb-
SET NOCOUNT OFF Kf_xKW)^
8、说明:更改某个表 $`lm]} {&
exec sp_changeobjectowner 'tablename','dbo' \,r*-jr
9、存储更改全部表 ]Tg@wMgI
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 2 )3oX
@OldOwner as NVARCHAR(128), ,t:P
@NewOwner as NVARCHAR(128) %~,Fe7#p
AS R.vOYzo
DECLARE @Name as NVARCHAR(128) yO,Jgn
DECLARE @Owner as NVARCHAR(128) i
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DECLARE @OwnerName as NVARCHAR(128) AlkHf]oB
DECLARE curObject CURSOR FOR N">#fYix
select 'Name' = name, oK$Krrs0&
'Owner' = user_name(uid) XODp[+xEEt
from sysobjects C
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where user_name(uid)=@OldOwner z4$9,p
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order by name w.#z>4#3-
OPEN curObject *'\ HG
FETCH NEXT FROM curObject INTO @Name, @Owner 4:pgZz!
WHILE(@@FETCH_STATUS=0) DsbTx.vA
BEGIN F^S]7{
if @Owner=@OldOwner 69apTx
begin 4=;j.=>0X
set @OwnerName = @OldOwner + '.' + rtrim(@Name) (U
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exec sp_changeobjectowner @OwnerName, @NewOwner 1LAd5X
end "fUNrhCx
-- select @name,@NewOwner,@OldOwner MUGoW;}v)
FETCH NEXT FROM curObject INTO @Name, @Owner RDjw|V
END O'{kNr{u
close curObject lnLy"f"zV
deallocate curObject 9Oo`4
GO GlRjbNW?Q
10、SQL SERVER中直接循环写入数据 yPs6_Qo!p
declare @i int >Gk<a
set @i=1 po,Ue>n/
while @i<30 *ZFF$0}
begin J9DI(`
insert into test (userid) values(@i) {9.UeVz
set @i=@i+1 z%iPk'^
end S8v?H|rm
小记存储过程中经常用到的本周,本月,本年函数 -;FAS3(wy
Dateadd(wk,datediff(wk,0,getdate()),-1) ;Krb/qr4_
Dateadd(wk,datediff(wk,0,getdate()),6) w5
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Dateadd(mm,datediff(mm,0,getdate()),0) 5X>~39(r
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) \NEk B&^n
Dateadd(yy,datediff(yy,0,getdate()),0) c h((u(G
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 7Z<GlNv
上面的SQL代码只是一个时间段 (n7{?`Yid
Dateadd(wk,datediff(wk,0,getdate()),-1) #g0N/
Dateadd(wk,datediff(wk,0,getdate()),6) x$D^Bh,
就是表示本周时间段. 9yWf*s<
下面的SQL的条件部分,就是查询时间段在本周范围内的: I,HtW ),
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) e6
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而在存储过程中 .kMnq8u
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) )N607 Fa-
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) O:pg+o&