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。 yvooM'R
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一、基础 iQ|,&K0d]
1、说明:创建数据库 ocl47)
CREATE DATABASE database-name yI.}3y{^5
2、说明:删除数据库 nJ*mEB
drop database dbname 2'<=H76
3、说明:备份sql server De
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--- 创建 备份数据的 device Awa|rIM
USE master g7 Md
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' -<51CD w,
--- 开始 备份 UhSh(E8p>
BACKUP DATABASE pubs TO testBack 9U=fJrj'u
4、说明:创建新表 5Hwo)S]r
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) VqClM
根据已有的表创建新表: Uc&6=5~Ys\
A:create table tab_new like tab_old (使用旧表创建新表) D,dHP-v
B:create table tab_new as select col1,col2... from tab_old definition only +-aU+7tu
5、说明:删除新表 \7t5U7v8U
drop table tabname 833%H`jQc
6、说明:增加一个列 uojh%@.4
Alter table tabname add column col type wAu[pWD'6;
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。 xv$)u<Ve
7、说明:添加主键: Alter table tabname add primary key(col) JXL9Gge
说明:删除主键: Alter table tabname drop primary key(col) @Xve qUUU
8、说明:创建索引:create [unique] index idxname on tabname(col....) S"P9Nf?9
删除索引:drop index idxname ;;YcuzQI3
注:索引是不可更改的,想更改必须删除重新建。 %|*nmIPq(
9、说明:创建视图:create view viewname as select statement Foe>}6~{?
删除视图:drop view viewname dgco*TIGO
10、说明:几个简单的基本的sql语句 P^8^1-b
选择:select * from table1 where 范围 V/3 {^Fcr
插入:insert into table1(field1,field2) values(value1,value2) ~[zFQ)([
删除:delete from table1 where 范围 .lvI8Jf~X
更新:update table1 set field1=value1 where 范围 b$v[@"1
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! rmPne8D=c(
排序:select * from table1 order by field1,field2 [desc] lk[G;=K:.
总数:select count as totalcount from table1 B0)`wsb_
求和:select sum(field1) as sumvalue from table1 ~IlF*Zz#}6
平均:select avg(field1) as avgvalue from table1 oI_oz0nHk
最大:select max(field1) as maxvalue from table1 -v;n"Zy1
最小:select min(field1) as minvalue from table1 aJ6#=G61l
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11、说明:几个高级查询运算词 7`blGzP_
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A: UNION 运算符 NV}RRs
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。 =de<WoKnu2
B: EXCEPT 运算符 W&+y(Z-t
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。 "YG\
C: INTERSECT 运算符 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。 1
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注:使用运算词的几个查询结果行必须是一致的。 NZo<IKD$
12、说明:使用外连接 X~v4"|a
A、left outer join: 5c:'>
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。 I!fB1aq-
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 cq*p9c
B:right outer join: _m9~*
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。 `E3:;|
C:full outer join: 2Vp>"
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。 X,RT<GNNb
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二、提升 R9tckRG#
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) O9t=lrYV!
法一:select * into b from a where 1<>1 N@Xg5huO
法二:select top 0 * into b from a DeOXM=&z
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) '8)Wd"[
insert into b(a, b, c) select d,e,f from b; -|m$YrzG
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) #_.g2 Y
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 koOy Z>
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. jrm0@K+<IA
4、说明:子查询(表名1:a 表名2:b) 2c}B
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) V~OUE]]Q
5、说明:显示文章、提交人和最后回复时间 O.*jR`l
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b {
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6、说明:外连接查询(表名1:a 表名2:b) O6y @G
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ~TYbP
7、说明:在线视图查询(表名1:a ) `[WyHO|8
select * from (SELECT a,b,c FROM a) T where t.a > 1; 7w "sJ
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 >9-Dd)<
select * from table1 where time between time1 and time2 0jBKCu
select a,b,c, from table1 where a not between 数值1 and 数值2 3YR *
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9、说明:in 的使用方法 6#<Ir @z
select * from table1 where a [not] in ('值1','值2','值4','值6') c}\
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10、说明:两张关联表,删除主表中已经在副表中没有的信息 !L4dUMo
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Dba+z-3Nzy
11、说明:四表联查问题: H}vn$$
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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 ..... 8NnhT E
12、说明:日程安排提前五分钟提醒 z>6.[Z(T
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 c
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13、说明:一条sql 语句搞定数据库分页 1'Nh jL
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 o
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14、说明:前10条记录 RNGO~:k?r
select top 10 * form table1 where 范围 P,(9cyS{
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.) j7f5|^/x3
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Ll,I-BQ9
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 mHKJ
(select a from tableA ) except (select a from tableB) except (select a from tableC) GF&_~48GD
17、说明:随机取出10条数据 XmP;L(wa
select top 10 * from tablename order by newid() avlqDi1l
18、说明:随机选择记录 F
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select newid() xXO RIlD
19、说明:删除重复记录 ZQ|5W6c
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) <BSSa`N`
20、说明:列出数据库里所有的表名 aZ$/<|y~:_
select name from sysobjects where type='U' FIH@2zA
21、说明:列出表里的所有的 C?,*U
select name from syscolumns where id=object_id('TableName') M3ZOk<O<R
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。 Q\H_t)-
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 v' C@jsxM
显示结果: JlUb0{8PE
type vender pcs vyE{WkZxR
电脑 A 1 5\WUoSgy
电脑 A 1 D>P;Izb
光盘 B 2 0}B?sNr
光盘 A 2 Q.yb4
手机 B 3 k=e`*LB\
手机 C 3 &1P(O\d
23、说明:初始化表table1 G(3;;F7"
TRUNCATE TABLE table1 )`^ /(YG
24、说明:选择从10到15的记录 byafb+x
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc G%;kGi`m
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三、技巧 }"hW b(
1、1=1,1=2的使用,在SQL语句组合时用的较多 hqL+_|DW
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 8yn4}`Nc@
如: /N>} 4Ay
if @strWhere !='' {#N%Bq}
begin E30Ln_^o
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere
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end t ^m~
else "v5ElYG
begin e^zHw^js
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' opXDm\
end i0\)%H:z
我们可以直接写成 nWk e#{[
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ;`+`#h3-V
2、收缩数据库 m^Glc?g<
--重建索引 Ls1B\Aw _
DBCC REINDEX q(gjT^aN
DBCC INDEXDEFRAG j1A|D
--收缩数据和日志 !.*iw
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DBCC SHRINKDB 9p4y>3
DBCC SHRINKFILE X &D{5~qC
3、压缩数据库 \9w~pO
dbcc shrinkdatabase(dbname) GV5qdD(
4、转移数据库给新用户以已存在用户权限 a$}NW.
exec sp_change_users_login 'update_one','newname','oldname' +pz}4M`
go >OK#n)U`
5、检查备份集 z3W3=@
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' [X<Pk
6、修复数据库 z6I% wh
ALTER DATABASE [dvbbs] SET SINGLE_USER d*2u}1Jo8
GO 6T_K9
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK *GJ:+U&m[
GO b!^@PIX
ALTER DATABASE [dvbbs] SET MULTI_USER U7h(-dV
GO a ~opE!|m
7、日志清除 w^Ag]HZN
SET NOCOUNT ON &<Zdyf?[Ou
DECLARE @LogicalFileName sysname, 8eN7VT eb
@MaxMinutes INT, \x(^]/@
@NewSize INT hO
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USE tablename -- 要操作的数据库名 s1bU
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 hO3{
@MaxMinutes = 10, -- Limit on time allowed to wrap log. /OG zt
@NewSize = 1 -- 你想设定的日志文件的大小(M) R&*@@F-dx
-- Setup / initialize {n&Uf{
DECLARE @OriginalSize int dxCPV6 XI
SELECT @OriginalSize = size H O*YBL
FROM sysfiles
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WHERE name = @LogicalFileName 'mE^5K
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 35_)3R)
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + s6n`?,vw
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' APq7 f8t
FROM sysfiles @^&7$#jq%
WHERE name = @LogicalFileName mlB~V3M'G
CREATE TABLE DummyTrans nxfoWy
(DummyColumn char (8000) not null) ~8{sA5y
DECLARE @Counter INT, KP{3iUqvO
@StartTime DATETIME, _{)9b24(
@TruncLog VARCHAR(255) s$ z2 c
SELECT @StartTime = GETDATE(), N 9LgU)-Jt
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' u okc:D
DBCC SHRINKFILE (@LogicalFileName, @NewSize) "%@v++4y
EXEC (@TruncLog) S)7/0N79A
-- Wrap the log if necessary. ix&'0IrX*
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired lP3h<j
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) orqJ[!u)`
AND (@OriginalSize * 8 /1024) > @NewSize y'
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BEGIN -- Outer loop. cU8x Upq
SELECT @Counter = 0 ||Y<f *
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Ryv_1gR!
BEGIN -- update S&wzB)#'
INSERT DummyTrans VALUES ('Fill Log') u-:Ic.ZV
DELETE DummyTrans 'SV7$,mK@
SELECT @Counter = @Counter + 1 "r$/
END )];aI A$
EXEC (@TruncLog) tJ'iX>9I
END snC/H G7
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 7u|B ](FS
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + wk @,wOt
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' [_.n$p-
FROM sysfiles 24B<[lSK
WHERE name = @LogicalFileName iKAusWj
DROP TABLE DummyTrans 3i=Iu0
SET NOCOUNT OFF |8U;m:AS
8、说明:更改某个表 B<,YPS8w
exec sp_changeobjectowner 'tablename','dbo' qINTCm j
9、存储更改全部表 izuF !9
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch /{*$JF
@OldOwner as NVARCHAR(128), Qihdn66
@NewOwner as NVARCHAR(128) Vte EDL/w
AS #{PmNx%M
DECLARE @Name as NVARCHAR(128) ppN} k)m
DECLARE @Owner as NVARCHAR(128) KY.ZT2k
DECLARE @OwnerName as NVARCHAR(128) 76@qHTh}
DECLARE curObject CURSOR FOR H=~9CJ+tc
select 'Name' = name, (MLhaux-
'Owner' = user_name(uid) +@:L|uFU
from sysobjects OfZN|S+~W
where user_name(uid)=@OldOwner -6C +LbV
order by name *9D!A
OPEN curObject ~x]9SXD%
FETCH NEXT FROM curObject INTO @Name, @Owner Dl,`\b@Fw3
WHILE(@@FETCH_STATUS=0) 2*1ft>Uty
BEGIN 7x k|+!
if @Owner=@OldOwner /+[63=fl
begin 1@qgF
set @OwnerName = @OldOwner + '.' + rtrim(@Name) [Qj;/
exec sp_changeobjectowner @OwnerName, @NewOwner <]d
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end E=w3=\JP
-- select @name,@NewOwner,@OldOwner nc?B6IV
FETCH NEXT FROM curObject INTO @Name, @Owner z]@6fM[
END c$h9/H=~
close curObject h"W8N+e\
deallocate curObject 5zB~4 u
GO -t-tn22
10、SQL SERVER中直接循环写入数据 [*4fwk^
declare @i int =.Tv)/ea
set @i=1 lFq{O;q7}
while @i<30 +!yXTC
begin bw S*]!*
insert into test (userid) values(@i) z&}-8JykH
set @i=@i+1 go'j/4Tp
end /'wF2UR
小记存储过程中经常用到的本周,本月,本年函数 :dnJY%/q
Dateadd(wk,datediff(wk,0,getdate()),-1) `u_Qa
Dateadd(wk,datediff(wk,0,getdate()),6) [hh/1[
Dateadd(mm,datediff(mm,0,getdate()),0) l=={pb
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 3z8C
Dateadd(yy,datediff(yy,0,getdate()),0) ,o#kRWRG
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) |i7a@'0)
上面的SQL代码只是一个时间段 iiC!|`k"
Dateadd(wk,datediff(wk,0,getdate()),-1) ))T>jh
Dateadd(wk,datediff(wk,0,getdate()),6) WAPhv-6
就是表示本周时间段. $xgBKD
下面的SQL的条件部分,就是查询时间段在本周范围内的: \'v(Xp6
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Z-X?JA\&
而在存储过程中 {/8Q)2*>0
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) {eT.SO
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) I'!/[\_