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。 !|O~$2O@
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一、基础 *Txl+zTY
1、说明:创建数据库 Fb7#<h
CREATE DATABASE database-name dZi(&s
2、说明:删除数据库 o3I Tr';
drop database dbname F{eU";D
3、说明:备份sql server `t_W2y
--- 创建 备份数据的 device (xVsDAp=@
USE master
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' %kB8'a3
--- 开始 备份 1_\;- !t
BACKUP DATABASE pubs TO testBack
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4、说明:创建新表 gF[z fDm
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) u>TZt]h8
根据已有的表创建新表: 4$*%gL;f^
A:create table tab_new like tab_old (使用旧表创建新表) e pU:
B:create table tab_new as select col1,col2... from tab_old definition only *M$0J'-BQ
5、说明:删除新表 q{t*34R
drop table tabname f}1&HI8r
6、说明:增加一个列 [ {
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Alter table tabname add column col type HYD"#m'TkB
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。 jBU4F~1y
7、说明:添加主键: Alter table tabname add primary key(col) $OP7l>KZY
说明:删除主键: Alter table tabname drop primary key(col) NGOqy+Ty{f
8、说明:创建索引:create [unique] index idxname on tabname(col....) z)9wXo#~
删除索引:drop index idxname E I:w
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注:索引是不可更改的,想更改必须删除重新建。 #B:hPZM1
9、说明:创建视图:create view viewname as select statement
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删除视图:drop view viewname ^4,a 8`
10、说明:几个简单的基本的sql语句 7.Z@Wr?
选择:select * from table1 where 范围 df
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插入:insert into table1(field1,field2) values(value1,value2) P#fM:z@[
删除:delete from table1 where 范围 |b-]n"}c>
更新:update table1 set field1=value1 where 范围 J41G&$j(
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! |7X:TfJ
排序:select * from table1 order by field1,field2 [desc] Hd,p!_
总数:select count as totalcount from table1 "
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求和:select sum(field1) as sumvalue from table1 |\U5),m
平均:select avg(field1) as avgvalue from table1 '1$!jmY
最大:select max(field1) as maxvalue from table1 [o.B
最小:select min(field1) as minvalue from table1 lWqrU1Sjl
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11、说明:几个高级查询运算词 7c~u=U"
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A: UNION 运算符 e0J6Ae4V[
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 v{9t]s>B
B: EXCEPT 运算符 Ma+$g1$
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。 7f~Sf
C: INTERSECT 运算符 ^`G`phd$
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。 rtL}W__
注:使用运算词的几个查询结果行必须是一致的。 glDh([
12、说明:使用外连接 ({NAMc*
A、left outer join: F35#dIs`&
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。 =IUUeFv +r
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 ^;Sy. W&`
B:right outer join: 1&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。 H6&J;yT}
C:full outer join: Bf$_XG3
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。 cZ<A0
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二、提升 &m[Qn!>i6
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Y;)dct
法一:select * into b from a where 1<>1 {U84 _Pi
法二:select top 0 * into b from a P|HKn,ar
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) F* .g;So
insert into b(a, b, c) select d,e,f from b; tqy@iEz+
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) #^4,GLIM
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 P)uDLFp]
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. hRq3C1mR
4、说明:子查询(表名1:a 表名2:b) NuYkz"O]
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) 11,!XD*"
5、说明:显示文章、提交人和最后回复时间 ;/0 Q1-
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b rYp3(k3
6、说明:外连接查询(表名1:a 表名2:b) rvyrxw%[
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 0jzbG]pc:E
7、说明:在线视图查询(表名1:a ) _ z;q9&J)
select * from (SELECT a,b,c FROM a) T where t.a > 1; W,K%c=
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 '}rRzD:
select * from table1 where time between time1 and time2 nN~~cV
select a,b,c, from table1 where a not between 数值1 and 数值2 1-PoZ[p-R
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') !sRngXCXk?
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Q0\0f
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) F|&{Rt
11、说明:四表联查问题: q|%(3,)ig
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 ..... 9<vWcq*4
12、说明:日程安排提前五分钟提醒 >j{z>
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 XK"-'
13、说明:一条sql 语句搞定数据库分页 !bC+TYsU
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 *c)uGz'cD
14、说明:前10条记录 )~V4+*<
select top 10 * form table1 where 范围 &h~Xq^
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.) Pub0IIs
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) J|3E- p\o
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 xP=/N!,#
(select a from tableA ) except (select a from tableB) except (select a from tableC) ,KJw|x4}\
17、说明:随机取出10条数据 5VO;s1
select top 10 * from tablename order by newid() #XnPsU<J
18、说明:随机选择记录 N-g8}03
select newid() BI:k#jO!
19、说明:删除重复记录 f""`cdqAOh
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 7?v#'Ies
20、说明:列出数据库里所有的表名 xBFJ} v
select name from sysobjects where type='U' "Pl9 nE
21、说明:列出表里的所有的 4 V1bLm
select name from syscolumns where id=object_id('TableName') `]v[5E
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{v8q)5r
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 Jd,)a#<j
显示结果: XM<KF&pVB
type vender pcs i-U4RZE
电脑 A 1
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电脑 A 1 E(Rh#+]Y5
光盘 B 2 rtQHWRUn
光盘 A 2 dx,=Rd5'
手机 B 3 N4K8
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手机 C 3 D^U:
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23、说明:初始化表table1 'O6]0l
TRUNCATE TABLE table1 ySbqnw'
24、说明:选择从10到15的记录 U6[ang'l
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc zNSu
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三、技巧 QFPfIb/
1、1=1,1=2的使用,在SQL语句组合时用的较多 W/=|/-\]/
"where 1=1" 是表示选择全部 "where 1=2"全部不选, YYg)
如: mqfO4"lt
if @strWhere !='' QIB>rQCceo
begin Ovw[b2ii
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere CY?G*nS?iK
end 0(8H;T
else ":Edu,6O
begin V2|3i}V"
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' *pzq.#
end "k$JP
我们可以直接写成 :RxHw;!
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere f]8I64
2、收缩数据库 4y}"Hy
--重建索引 W&"|}Pi/
DBCC REINDEX '[ P}&<ie,
DBCC INDEXDEFRAG nL]^$J$
--收缩数据和日志 L3(^{W]|
DBCC SHRINKDB /"qcl7F
DBCC SHRINKFILE ?lCd{14Mkh
3、压缩数据库 ! o,5h|\
dbcc shrinkdatabase(dbname) io4A>>W==/
4、转移数据库给新用户以已存在用户权限 e yw'7
exec sp_change_users_login 'update_one','newname','oldname' {Z{o"56f
go oCi
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5、检查备份集 >
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Ja^ 5?Ar|
6、修复数据库 g+zJ?
ALTER DATABASE [dvbbs] SET SINGLE_USER ;eB ~H[S/
GO a?cn9i)#
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK HO|-@yOF^
GO KT*:F(4`
ALTER DATABASE [dvbbs] SET MULTI_USER {#Q\z>
GO CidM(
7、日志清除 u~ F;xQ
SET NOCOUNT ON @u4=e4eF`
DECLARE @LogicalFileName sysname, &;q<M_<
@MaxMinutes INT, i&+w _hD
@NewSize INT @y~P&HUN
USE tablename -- 要操作的数据库名 vrl[BPI
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 &w~Xa( uu
@MaxMinutes = 10, -- Limit on time allowed to wrap log. X.|Ygx
@NewSize = 1 -- 你想设定的日志文件的大小(M) >X Qv?5
-- Setup / initialize hY\{|
DECLARE @OriginalSize int ?H;{~n?
SELECT @OriginalSize = size f5dR 5G
FROM sysfiles (
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WHERE name = @LogicalFileName ?p8Qx\%*
SELECT 'Original Size of ' + db_name() + ' LOG is ' + |DG@ht
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + )q?$p9
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ,I*X)(
FROM sysfiles 2g`[u|
WHERE name = @LogicalFileName M?6;|-HH
CREATE TABLE DummyTrans X}JWf<=q
(DummyColumn char (8000) not null) 5h_5Z~
DECLARE @Counter INT, R ZcH+?7
@StartTime DATETIME, jq oPLbxT
@TruncLog VARCHAR(255) saK;[&I*
SELECT @StartTime = GETDATE(), u35q,u=I
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ]O{_O&w
DBCC SHRINKFILE (@LogicalFileName, @NewSize) wa3F
EXEC (@TruncLog) Sni=gZ K
-- Wrap the log if necessary. $iJnxqn
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired [ #]jC[
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) j=3-Qk`"/|
AND (@OriginalSize * 8 /1024) > @NewSize LcUlc)YH5
BEGIN -- Outer loop. u(vw|nj`
SELECT @Counter = 0 (wL3 +
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) O3_B<Em
BEGIN -- update !UNNjBBP7
INSERT DummyTrans VALUES ('Fill Log') V<0$xV1b|=
DELETE DummyTrans ,t~sV@ap
SELECT @Counter = @Counter + 1 qC
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END T Oy7?;|=
EXEC (@TruncLog) _g6wQdxT
END ~/c5hyTx
SELECT 'Final Size of ' + db_name() + ' LOG is ' + m "]!I~jd
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + O)5#Fcp(
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ,C!n}+27
FROM sysfiles rt.[,m
WHERE name = @LogicalFileName b>=7B6 Aw
DROP TABLE DummyTrans )fCMITq.|
SET NOCOUNT OFF (v;A'BjN
8、说明:更改某个表 Jr?!Mh-
exec sp_changeobjectowner 'tablename','dbo' 5'9.np F)
9、存储更改全部表 hZF(/4Z2
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch C={mi#G[/
@OldOwner as NVARCHAR(128), 7|~:P$M
@NewOwner as NVARCHAR(128) hO;9Y|y
AS !fZLQc
DECLARE @Name as NVARCHAR(128) C9Wojo.
DECLARE @Owner as NVARCHAR(128) $h]NXC6J
DECLARE @OwnerName as NVARCHAR(128) >ZDC . ~
DECLARE curObject CURSOR FOR 00qZw?%K
select 'Name' = name, J{H?xc
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'Owner' = user_name(uid) 62NkU)u
from sysobjects >Fh#DmQ
where user_name(uid)=@OldOwner IDmsz
order by name |$Xf;N37t
OPEN curObject y*|L:!
FETCH NEXT FROM curObject INTO @Name, @Owner
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WHILE(@@FETCH_STATUS=0) J(hA^;8:
BEGIN C,='3^Nc
if @Owner=@OldOwner u2,H ]-
begin <|Iyt[s
set @OwnerName = @OldOwner + '.' + rtrim(@Name) K Dz]wNf
exec sp_changeobjectowner @OwnerName, @NewOwner .' IeHh
end i"fCpkAP
-- select @name,@NewOwner,@OldOwner R}.3|0
FETCH NEXT FROM curObject INTO @Name, @Owner yjR)Z9t
END VK$zq5D
close curObject m|`VJ0
deallocate curObject 2@5A&b
GO l }+Cdy9>
10、SQL SERVER中直接循环写入数据 5"e+& zU~f
declare @i int ytob/tc
set @i=1 ?GfxBZWJ
while @i<30
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begin %U:C|
insert into test (userid) values(@i) ( w5f(4
set @i=@i+1 E7gL~4I
end ?AT(S
小记存储过程中经常用到的本周,本月,本年函数 PgTDjEo
Dateadd(wk,datediff(wk,0,getdate()),-1) g X8**g'
Dateadd(wk,datediff(wk,0,getdate()),6) "bi !=
Dateadd(mm,datediff(mm,0,getdate()),0) ?}v}U^
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) J[MVE4&
Dateadd(yy,datediff(yy,0,getdate()),0) uh1S
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) y78z>(jV
上面的SQL代码只是一个时间段 }*Dd/'2+1
Dateadd(wk,datediff(wk,0,getdate()),-1) k|l5 "&K~.
Dateadd(wk,datediff(wk,0,getdate()),6) "s>
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就是表示本周时间段. ?|)rv
下面的SQL的条件部分,就是查询时间段在本周范围内的: 4"z;CGE7
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ?&XzW+(X
而在存储过程中 @N]5&4NL
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) (A2U~j?Ry}
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) qZ233pc