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。 ot&j HS'
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一、基础 h'z+8X_t
1、说明:创建数据库 Y0R\u\b
CREATE DATABASE database-name v)X[gt
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2、说明:删除数据库 +-xSuR,
drop database dbname '` BjRg57]
3、说明:备份sql server +Y_Q?/M@8
--- 创建 备份数据的 device y$+!%y*
USE master ljaAB+
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' UtHmM,*I
--- 开始 备份 hnM9-hqm
BACKUP DATABASE pubs TO testBack !xJLeQFJI]
4、说明:创建新表
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) !07FsPI#{
根据已有的表创建新表: xF\}.OfWG
A:create table tab_new like tab_old (使用旧表创建新表)
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B:create table tab_new as select col1,col2... from tab_old definition only p0%6@_FT~
5、说明:删除新表 3M`hn4)K
drop table tabname uaZ"x&oZ#
6、说明:增加一个列 ru(?a~lF8~
Alter table tabname add column col type q329z>
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 (9'G
7、说明:添加主键: Alter table tabname add primary key(col) o}j_eHl{
说明:删除主键: Alter table tabname drop primary key(col) 'Kt4O9=p
8、说明:创建索引:create [unique] index idxname on tabname(col....) %Hh &u
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删除索引:drop index idxname <
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注:索引是不可更改的,想更改必须删除重新建。 Rz])wBv e
9、说明:创建视图:create view viewname as select statement S|z(
删除视图:drop view viewname x _YV{
10、说明:几个简单的基本的sql语句 9/8@
选择:select * from table1 where 范围 J%O[@jX1
插入:insert into table1(field1,field2) values(value1,value2) NoSqzJyh
删除:delete from table1 where 范围 W}<M?b4tP
更新:update table1 set field1=value1 where 范围 |yId6v
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! * 7zN
排序:select * from table1 order by field1,field2 [desc] 8Pnqmjjj
总数:select count as totalcount from table1 tOlzOBzR
求和:select sum(field1) as sumvalue from table1 umHs " d
平均:select avg(field1) as avgvalue from table1 <7sF<KD
最大:select max(field1) as maxvalue from table1 |{}d5Z"5;}
最小:select min(field1) as minvalue from table1 ?$`1%Y9
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11、说明:几个高级查询运算词 2yQ;lQ`
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A: UNION 运算符 JXZ:Wg
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。 Cx1Sh#9
B: EXCEPT 运算符 z!t3xFN&/
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。 Kr+Bty
C: INTERSECT 运算符 :Z7"c`6L!~
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。 x"h)"Y[c5
注:使用运算词的几个查询结果行必须是一致的。 :a^,Ei-&
12、说明:使用外连接 gw}7%U`T9
A、left outer join: zN729wK
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。 {) '"
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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 jT wM<?
B:right outer join: L;(3u'
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。 <|>:UGAR
C:full outer join: '8kL1
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。 j_YZ(: =
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二、提升 bW 79<T'+
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) KzFs#rhpn
法一:select * into b from a where 1<>1 @Tm0T7C
法二:select top 0 * into b from a -$!Pf$l@
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Af!
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insert into b(a, b, c) select d,e,f from b; 7+2aG
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) bju,p"J1-E
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 +XaO?F[c
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. _c7
4、说明:子查询(表名1:a 表名2:b) ~]t2?SqNm
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) yI)RGOV
5、说明:显示文章、提交人和最后回复时间 (/rIodHJO
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b (^@;`8Dy8
6、说明:外连接查询(表名1:a 表名2:b) uBL~AC3>O
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c xr7<(:d
7、说明:在线视图查询(表名1:a ) :O@,Z_"
select * from (SELECT a,b,c FROM a) T where t.a > 1; X:} 5L>'
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 R;,u >P "
select * from table1 where time between time1 and time2 \5L 4*
select a,b,c, from table1 where a not between 数值1 and 数值2 AQBx
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9、说明:in 的使用方法 `X]2iz
select * from table1 where a [not] in ('值1','值2','值4','值6') /\Y%DpG$
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ~ @"Qm;}
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) gCBZA;/
11、说明:四表联查问题:
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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 ..... iRr&'k
12、说明:日程安排提前五分钟提醒 M6 >\R$
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 0T{Y_IG
13、说明:一条sql 语句搞定数据库分页 9[]"%6
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 gQzJ2LU(
14、说明:前10条记录 1_E3DXe
select top 10 * form table1 where 范围 :92a34
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.) HuLm!tCu
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) `5 v51TpH
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 9QM"JEu@
(select a from tableA ) except (select a from tableB) except (select a from tableC) {CyPcD'$s
17、说明:随机取出10条数据 C?<XtIoB
select top 10 * from tablename order by newid() }JTgj
18、说明:随机选择记录 .^+$w$
select newid() 2W-NCE%K)T
19、说明:删除重复记录 y7L4jO9h
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) >A@D;vx
20、说明:列出数据库里所有的表名 >~bj7M6t
select name from sysobjects where type='U' bJMcI8`
21、说明:列出表里的所有的 ST[1'T+L
select name from syscolumns where id=object_id('TableName') qFsg&<
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。 o4
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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 Y
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显示结果: j!8+|eAkk
type vender pcs kk7:A0._
电脑 A 1 ~X(xa
电脑 A 1 !{ )AV/\D
光盘 B 2 k^%ec3l
光盘 A 2 ZCF-*nm
手机 B 3 W2LblZE!
手机 C 3 IF?B`TmZ
23、说明:初始化表table1 3*23+}^G
TRUNCATE TABLE table1 V$F.`O!hfi
24、说明:选择从10到15的记录 *gpD4c7A\
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ,ce^"yG
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三、技巧 o)D+qiA3U
1、1=1,1=2的使用,在SQL语句组合时用的较多 dGW7,B~
"where 1=1" 是表示选择全部 "where 1=2"全部不选, vgp%;-p(
如: CH+&
if @strWhere !='' "9T`3cM0
begin jHw2Q8s|R
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere A-`J!xj#/
end =Bqa<Js
else =X'7V}Q}
begin w3cK:
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' "}aM*(l+\
end \osQwGPV
我们可以直接写成 :Ty*i
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere [k{iN1n
2、收缩数据库 Q>c6ouuJ
--重建索引 '9Odw@tp
DBCC REINDEX .`#R%4Xl
DBCC INDEXDEFRAG `-YSFQ~O,
--收缩数据和日志 kxf=%<l
DBCC SHRINKDB s^@Cq=
DBCC SHRINKFILE k_^/
3、压缩数据库 _5`S)G{
dbcc shrinkdatabase(dbname) 54DR .>O
4、转移数据库给新用户以已存在用户权限 X',0MBQ0
exec sp_change_users_login 'update_one','newname','oldname' q _|5,_a
go 2/q=l?
5、检查备份集 ]<z(Rmn`Q
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' exKmK!FT
6、修复数据库 cW^)$>A
ALTER DATABASE [dvbbs] SET SINGLE_USER i1Sc/
GO ~"0X,APR5
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK _%%"Y}
GO (>`SS#(T!
ALTER DATABASE [dvbbs] SET MULTI_USER
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;
GO w:+#,,rwzV
7、日志清除 Bzt`9lg
SET NOCOUNT ON E}j8p_p
DECLARE @LogicalFileName sysname, zFQkUgb
@MaxMinutes INT, Y rnqi-P
@NewSize INT |^{" 2l"j
USE tablename -- 要操作的数据库名 u(`A?H:
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 O!Cu.9}
@MaxMinutes = 10, -- Limit on time allowed to wrap log. (,y/nc=GN
@NewSize = 1 -- 你想设定的日志文件的大小(M)
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-- Setup / initialize ?^5*[H
DECLARE @OriginalSize int uL AXN
SELECT @OriginalSize = size FQ1oqqr
FROM sysfiles *lF%8k"Al
WHERE name = @LogicalFileName 3(p6ak2lv
SELECT 'Original Size of ' + db_name() + ' LOG is ' + Q8:ocEhR
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + o_m.MMEU
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' g$LwXfg
FROM sysfiles &J M;jSz
WHERE name = @LogicalFileName }Cg~::,"
CREATE TABLE DummyTrans N0hU~| /
(DummyColumn char (8000) not null) IomJo
DECLARE @Counter INT, #vwXx r
@StartTime DATETIME, kovzB]
@TruncLog VARCHAR(255) JAlsc]XtO9
SELECT @StartTime = GETDATE(), 74Wg@!P
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Wy )g449
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ?M(Wx
EXEC (@TruncLog) 'PbA/MN
-- Wrap the log if necessary. 6\@, Lb
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired DK%eFCo<~
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) |%;txD
AND (@OriginalSize * 8 /1024) > @NewSize X;>} ;LiK
BEGIN -- Outer loop. =upP3rw
SELECT @Counter = 0 H;&t"Ql.
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) P9wDTZ
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BEGIN -- update nQmYeM
INSERT DummyTrans VALUES ('Fill Log') +[`%b3N k
DELETE DummyTrans 5~0;R`D
SELECT @Counter = @Counter + 1 LdUpVO8)l
END ;mlIWn
EXEC (@TruncLog) ]~ UkD*Ct
END _S1uJ~j;E
SELECT 'Final Size of ' + db_name() + ' LOG is ' + RVx<2,['
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + k<qH<<r*
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' .CpO+z
FROM sysfiles l/NK.Jr
WHERE name = @LogicalFileName XS/TYdXB8
DROP TABLE DummyTrans !YHu
SET NOCOUNT OFF ZW%`G@d"H-
8、说明:更改某个表 1X.1t^HH:
exec sp_changeobjectowner 'tablename','dbo' J)NpG9iN
9、存储更改全部表 e[!>ezaIY
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch eO G%6C%a
@OldOwner as NVARCHAR(128), )>p6h]]a
@NewOwner as NVARCHAR(128) o#6}?g.
AS 6P|neb}
DECLARE @Name as NVARCHAR(128) oFp&j@`k8j
DECLARE @Owner as NVARCHAR(128) sAlgp2-
DECLARE @OwnerName as NVARCHAR(128) ztpb/9J9
DECLARE curObject CURSOR FOR ;v\n[
select 'Name' = name, (J*0/7
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'Owner' = user_name(uid) mNKa~E
from sysobjects
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where user_name(uid)=@OldOwner ~]W8NaQB(
order by name 8{u01\0}
OPEN curObject $ 1ZY
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FETCH NEXT FROM curObject INTO @Name, @Owner ?|dz"=y
WHILE(@@FETCH_STATUS=0) h6t>yC\
BEGIN }JsdgO&z
if @Owner=@OldOwner l!,{bOZ
begin *Rd&4XG
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ,L G&sa"
exec sp_changeobjectowner @OwnerName, @NewOwner p3' +"sFU
end _T$\$v$ {
-- select @name,@NewOwner,@OldOwner T-TH.
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FETCH NEXT FROM curObject INTO @Name, @Owner qQ_QF
END JhcS
close curObject GZo4uwG@a
deallocate curObject <~OyV5:6
GO ND>}t#^$
10、SQL SERVER中直接循环写入数据 _#:1Axx1
declare @i int rGWTpN
set @i=1 -tQ|&fl
while @i<30 .w~USJ=X
begin )EoG@:[
insert into test (userid) values(@i) BR'|hG
set @i=@i+1 ~7
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end u+_#qk0NfK
小记存储过程中经常用到的本周,本月,本年函数 *$!LRmp?
Dateadd(wk,datediff(wk,0,getdate()),-1) '\Ub*m((1O
Dateadd(wk,datediff(wk,0,getdate()),6) Qp,l>k
Dateadd(mm,datediff(mm,0,getdate()),0) TfPx
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) O]>`B{
Dateadd(yy,datediff(yy,0,getdate()),0) ;l'I.j
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) o[6hUX0tN
上面的SQL代码只是一个时间段 l;uEw
Dateadd(wk,datediff(wk,0,getdate()),-1) d9(F wmE
Dateadd(wk,datediff(wk,0,getdate()),6) =j0V/=
就是表示本周时间段. [>;O'>
下面的SQL的条件部分,就是查询时间段在本周范围内的: A?/?9Gr
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) rxARJso
而在存储过程中 2wd(0K}b
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) $c-3Q|C
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ;
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