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。 3u
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一、基础 N&G'i.w/
1、说明:创建数据库 D zD5n
CREATE DATABASE database-name fDDpR=
2、说明:删除数据库 <h#7;o
drop database dbname o1#3A
3、说明:备份sql server #)}BY"C%
--- 创建 备份数据的 device C] Fw*t
USE master Do(G;D`h+_
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 7l7VT?<:
--- 开始 备份 &/[MWQ
BACKUP DATABASE pubs TO testBack sq=EL+=j
4、说明:创建新表 b;
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Hx6ODj[-
根据已有的表创建新表: ]0'cdC
A:create table tab_new like tab_old (使用旧表创建新表) s 4rva G@a
B:create table tab_new as select col1,col2... from tab_old definition only jUE:QOfRib
5、说明:删除新表 >h8m8J
drop table tabname m|fcWN[
6、说明:增加一个列 AO`@&e]o
Alter table tabname add column col type XcNL\fl1
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。 HIw)HYF2
7、说明:添加主键: Alter table tabname add primary key(col) s YTJ^K d
说明:删除主键: Alter table tabname drop primary key(col) T%.Yso{
8、说明:创建索引:create [unique] index idxname on tabname(col....) DSHvBFQ
删除索引:drop index idxname ;q'-<O
注:索引是不可更改的,想更改必须删除重新建。 D,=~7/g
9、说明:创建视图:create view viewname as select statement 8\;, d
删除视图:drop view viewname NUM!'+H_h
10、说明:几个简单的基本的sql语句 5$+7Q$Gw
选择:select * from table1 where 范围 UA'bE~i
插入:insert into table1(field1,field2) values(value1,value2) o`,}b1lh
删除:delete from table1 where 范围 *i*\dl
更新:update table1 set field1=value1 where 范围 0fstEExw
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! lO\HchGzB
排序:select * from table1 order by field1,field2 [desc] WCd:(8B
总数:select count as totalcount from table1 +E9G"Z65iP
求和:select sum(field1) as sumvalue from table1 &M5v EPR
平均:select avg(field1) as avgvalue from table1 ,W+=N"`a'
最大:select max(field1) as maxvalue from table1 ,l AZ4
最小:select min(field1) as minvalue from table1
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11、说明:几个高级查询运算词 $G <r2lPy
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A: UNION 运算符 N'{Yhx u
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。 ~I N g9|
B: EXCEPT 运算符 :kcqf,7
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 <`-sS]=d}
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。 o.Ww.F
注:使用运算词的几个查询结果行必须是一致的。 QN;5+p[N
12、说明:使用外连接 Mm,\e6#*
A、left outer join: M5RN Z%
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。 M
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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 #<Y3*^~5d
B:right outer join: CSjd&G*ZB
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。 A ___|
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C:full outer join: Ma\%uEgTD
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。 5Kd"W,
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二、提升 EyR/
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) vg?(0Gasm*
法一:select * into b from a where 1<>1 6{d?3Jk
法二:select top 0 * into b from a >4bw4
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) :!Z |_y{b
insert into b(a, b, c) select d,e,f from b; 7`~0j6FY
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) ~c&sr5E
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 |5>A^a
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. O*+HK1q7
4、说明:子查询(表名1:a 表名2:b) /)v+|%U
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) 5G6 P p7[
5、说明:显示文章、提交人和最后回复时间 N/lEfy<&g:
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b LV9R ]
6、说明:外连接查询(表名1:a 表名2:b) >l-u{([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 3W ]zLUn
7、说明:在线视图查询(表名1:a ) uN?Lz1W\;
select * from (SELECT a,b,c FROM a) T where t.a > 1; Hwd^C2v
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 VO1
select * from table1 where time between time1 and time2 ai/]E6r
select a,b,c, from table1 where a not between 数值1 and 数值2 i+QVs_jW
9、说明:in 的使用方法 _Cf:\Xs
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select * from table1 where a [not] in ('值1','值2','值4','值6') nGTGX
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Ax|'uvVAPT
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) CUdpT$ $x3
11、说明:四表联查问题: .>,Y
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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 ..... f3,LX]zKA
12、说明:日程安排提前五分钟提醒 D;2V|CkU
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 3qGz(6w6E
13、说明:一条sql 语句搞定数据库分页 3,Z;J5VL4!
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 )y:M8((%
14、说明:前10条记录 K_t >T)K
select top 10 * form table1 where 范围 :xmj42w>^
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.) oGZuYpa9
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) <%^WZ:c
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 <% mD#S
(select a from tableA ) except (select a from tableB) except (select a from tableC) VxOWv8}|
17、说明:随机取出10条数据 ;L",K?6#
select top 10 * from tablename order by newid() Q7`)&^
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18、说明:随机选择记录 N:'GNMu
select newid() A'}!'1
19、说明:删除重复记录 V@RdvQy
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) _nzTd\L88
20、说明:列出数据库里所有的表名 X:f5t` ;
select name from sysobjects where type='U' %d-WQwJ
21、说明:列出表里的所有的 (-1{W^(
select name from syscolumns where id=object_id('TableName') NH5sV.vvc
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。 t?^!OJ:L
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 t~}c"|<t
显示结果: 6 ym$8^
type vender pcs GGLSmfb)
电脑 A 1 ,|8aDL?
电脑 A 1 irw5<l
光盘 B 2 RI<smt.Ng
光盘 A 2 EGFP$nvq
手机 B 3 wYFkGih
手机 C 3 zNGUll$
23、说明:初始化表table1 }#~E-N3x
TRUNCATE TABLE table1 v 9G~i
24、说明:选择从10到15的记录 a`9pHH:7Q
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc -#<{3BJTrz
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三、技巧 D'moy*E
1、1=1,1=2的使用,在SQL语句组合时用的较多 rkh%[o9"/
"where 1=1" 是表示选择全部 "where 1=2"全部不选, .`u8(S+
如: Bk~lM'
if @strWhere !='' ZJFF4($qN
begin >^W6'Q$P<
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere vEG7A$Z"
end c9@3=6S/
else }"RVUYU
begin 4a!%eBhX"K
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' SH"<f_
end um<$L
我们可以直接写成 r.u\qPT&
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 2u0B=0x
2、收缩数据库 "`S?q G
--重建索引 toj5b;+4F
DBCC REINDEX vG)B}`M
DBCC INDEXDEFRAG 04-@c
--收缩数据和日志 jpXbFWgN
DBCC SHRINKDB 9!r0uU"
DBCC SHRINKFILE f;+.j/ +
3、压缩数据库 mJ[_q>
dbcc shrinkdatabase(dbname) @az<D7j2
4、转移数据库给新用户以已存在用户权限 $6ucz'
exec sp_change_users_login 'update_one','newname','oldname' oFt_ yU-
go h1B_*L
5、检查备份集 xe.f]a
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 1NTx?JJfW
6、修复数据库 rHybP6C<
ALTER DATABASE [dvbbs] SET SINGLE_USER l7<VH z0b
GO AU}|o0Ur
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 2A*,9S|Y
GO 4QPHT#e qX
ALTER DATABASE [dvbbs] SET MULTI_USER >#;_Ebl@
GO 2w~Vb0
7、日志清除 8"LM:0x
SET NOCOUNT ON <JXHg,Q
DECLARE @LogicalFileName sysname, &{# 6Z
@MaxMinutes INT, 5yJ~ q
@NewSize INT J?E!\V&U
USE tablename -- 要操作的数据库名 ^%6f%]_
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 QYj 4D
@MaxMinutes = 10, -- Limit on time allowed to wrap log. sVnq|[ /
@NewSize = 1 -- 你想设定的日志文件的大小(M) 1o_Zw.
-- Setup / initialize !K= $Q Uq
DECLARE @OriginalSize int ^[+2P?^K
SELECT @OriginalSize = size "9~KVILlLu
FROM sysfiles cYOcl-*af
WHERE name = @LogicalFileName 9N2.:<so
SELECT 'Original Size of ' + db_name() + ' LOG is ' + N!tNRMTi
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Aj O{c=d
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' #K` [XA
FROM sysfiles JvCy&xrE;
WHERE name = @LogicalFileName 8MU7|9 Q
CREATE TABLE DummyTrans BHkicb ?
(DummyColumn char (8000) not null) U3M;{_g
DECLARE @Counter INT, 5ff5M=M
@StartTime DATETIME, 1} _<q k9
@TruncLog VARCHAR(255) jCx*{TO
SELECT @StartTime = GETDATE(), 1xsJz^%V
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ;<cCT!A
DBCC SHRINKFILE (@LogicalFileName, @NewSize) fI.X5c>WK
EXEC (@TruncLog) vZ6R>f
-- Wrap the log if necessary. 3UQBIrQ
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired l Ny<E!0
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) LR4W
AND (@OriginalSize * 8 /1024) > @NewSize n(n7"+B
BEGIN -- Outer loop. #!m^EqF1_
SELECT @Counter = 0 l4I',79l
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Y_XRf8Sw
BEGIN -- update jrm^n_6};
INSERT DummyTrans VALUES ('Fill Log') 3EA_-?
DELETE DummyTrans OzxiT +
SELECT @Counter = @Counter + 1 !QqVJ a{j
END od !s5f!
EXEC (@TruncLog) zQGj,EAM}
END qM>Dt
SELECT 'Final Size of ' + db_name() + ' LOG is ' + W3X;c*j
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + @P=n{-pIW
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 6@d/k.3p
FROM sysfiles 96gaun J
WHERE name = @LogicalFileName xo-{N[r
DROP TABLE DummyTrans @te}Asv
SET NOCOUNT OFF jC-`u-_'j
8、说明:更改某个表 B>"-8#B[4
exec sp_changeobjectowner 'tablename','dbo' 11!4#z6w
9、存储更改全部表 a6d|Ps.\!
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch mkgL/h*
@OldOwner as NVARCHAR(128), K|;L{[[yH
@NewOwner as NVARCHAR(128) <BdC#t:*L
AS %u Dd#+{
DECLARE @Name as NVARCHAR(128) ~jWpD7px
DECLARE @Owner as NVARCHAR(128) UU#$Kt*frR
DECLARE @OwnerName as NVARCHAR(128) idS+&:'
DECLARE curObject CURSOR FOR %yR80mn8
select 'Name' = name, @ L/i
'Owner' = user_name(uid) -H5-6w$
from sysobjects 3m~3l d
where user_name(uid)=@OldOwner *JWPt(bnI
order by name cvpZF5mL]U
OPEN curObject (5 RZLRn
FETCH NEXT FROM curObject INTO @Name, @Owner &k(tDP
WHILE(@@FETCH_STATUS=0) )1)&fN41i#
BEGIN IJ{VCzi
if @Owner=@OldOwner Z#GR)jb+
begin \x_$Pu
set @OwnerName = @OldOwner + '.' + rtrim(@Name) {PL,3EBG
exec sp_changeobjectowner @OwnerName, @NewOwner On+0@hh
end B]>rcjD
-- select @name,@NewOwner,@OldOwner ]go.IfH
FETCH NEXT FROM curObject INTO @Name, @Owner nF
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END iZ(p]0aP7
close curObject 1u*
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deallocate curObject X(]J\?n'
GO On@p5YRwW
10、SQL SERVER中直接循环写入数据 {#+'T 13sx
declare @i int ,(+ZD@Rg
set @i=1 G<~P||Lu^
while @i<30 I%0J=V;o{
begin #vR5a}BAk
insert into test (userid) values(@i) Y~OyoNu2
set @i=@i+1 7l'1
end .4=A:9
小记存储过程中经常用到的本周,本月,本年函数 d%1Vby
Dateadd(wk,datediff(wk,0,getdate()),-1) `_{,4oi
Dateadd(wk,datediff(wk,0,getdate()),6) oTpoh]|[
Dateadd(mm,datediff(mm,0,getdate()),0) z2dW)_fU$
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Ap}`Q(.
Dateadd(yy,datediff(yy,0,getdate()),0) 4DGKZh'm"
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) \JF 2'm\M
上面的SQL代码只是一个时间段 ><)fK5x
Dateadd(wk,datediff(wk,0,getdate()),-1) kChCo0Q>1
Dateadd(wk,datediff(wk,0,getdate()),6) uD`Z\@Z
就是表示本周时间段. hnv0Loe.IW
下面的SQL的条件部分,就是查询时间段在本周范围内的: DH4|lb}
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 1a#R7chl
而在存储过程中 ve*6WDK,H
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) (`f)Tt=`
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ("J_< p