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。 #6g9@tE
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一、基础 \xCI8 *W
1、说明:创建数据库 ?=u/&3Cw
CREATE DATABASE database-name cy_'QS$W
2、说明:删除数据库 j 3/ I=
drop database dbname hk5[ N=
3、说明:备份sql server 11"- taWj
--- 创建 备份数据的 device /#<R
USE master sxG8jD
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' +,;"?j6<p
--- 开始 备份 R_DstpsT
BACKUP DATABASE pubs TO testBack 1w`]2
4、说明:创建新表 /z=xEnU#
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 2wCSjAWWh(
根据已有的表创建新表: 2OA0rH"v
A:create table tab_new like tab_old (使用旧表创建新表) cWp5' e]A
B:create table tab_new as select col1,col2... from tab_old definition only W;Pdbf"
5、说明:删除新表 3VI[*b
drop table tabname Fx@ovI- 5
6、说明:增加一个列 g?7I7W~?`
Alter table tabname add column col type kjj4%0"
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。 F.rNh`44
7、说明:添加主键: Alter table tabname add primary key(col) OM>,1;UH]
说明:删除主键: Alter table tabname drop primary key(col) YLXLaC[
8、说明:创建索引:create [unique] index idxname on tabname(col....) Gt4/ax:A@
删除索引:drop index idxname :.VI*X:aQh
注:索引是不可更改的,想更改必须删除重新建。 V
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9、说明:创建视图:create view viewname as select statement z`}<mY
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删除视图:drop view viewname %>];F~z
10、说明:几个简单的基本的sql语句 Ee~<PDzB
选择:select * from table1 where 范围 biLNR"/E
插入:insert into table1(field1,field2) values(value1,value2) +6zW(Ql/
删除:delete from table1 where 范围 k?bIu
更新:update table1 set field1=value1 where 范围 6%-RKQi
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! L'Yg$9 Vz
排序:select * from table1 order by field1,field2 [desc] h0cdRi
总数:select count as totalcount from table1 LL0Y$pHV
求和:select sum(field1) as sumvalue from table1 K'6NW:zp~
平均:select avg(field1) as avgvalue from table1 '3i,^g0?t0
最大:select max(field1) as maxvalue from table1 ]2_b_ok
最小:select min(field1) as minvalue from table1 _ww>u""B~
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11、说明:几个高级查询运算词 S^8C\ E
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A: UNION 运算符 hR4\:s+[
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。 .S_7R/2(?
B: EXCEPT 运算符 VxP cC+
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。 t6,bA1*5y
C: INTERSECT 运算符 cko^_V&x
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。 wB(X(nr
注:使用运算词的几个查询结果行必须是一致的。 = :/4)
12、说明:使用外连接 `iQ])C^d
A、left outer join: B,5kG{2!
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。 a 23XrX
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 *HONA>u
B:right outer join: UR|Au'iu
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。 {}n]\zO %
C:full outer join: 3>'TYXs-
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?:e4:Q
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二、提升 Bs3M7zRG
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) !,cLc}a
法一:select * into b from a where 1<>1 QomihQnc
法二:select top 0 * into b from a : MEB] }
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) /ucS*m:<x
insert into b(a, b, c) select d,e,f from b; #FhgKwx
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) "-
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 6 uTFgSqZ
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. mB5Sm|{
4、说明:子查询(表名1:a 表名2:b) ufi:aE=}
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) L%`MoTpKq
5、说明:显示文章、提交人和最后回复时间 n~Yr`5+Z
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b rj
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6、说明:外连接查询(表名1:a 表名2:b) $~,J8?)(z
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 2CF5qn}T
7、说明:在线视图查询(表名1:a ) FokSg[)5
select * from (SELECT a,b,c FROM a) T where t.a > 1; (&KBYiwr
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 u9*7Buou^
select * from table1 where time between time1 and time2 dFl8 'D
select a,b,c, from table1 where a not between 数值1 and 数值2 uqsVq0H
9、说明:in 的使用方法 b[2 #t
select * from table1 where a [not] in ('值1','值2','值4','值6') 3Fg{?C_l
10、说明:两张关联表,删除主表中已经在副表中没有的信息 W9G1wU
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) E)iX`Xq|0{
11、说明:四表联查问题: xG1(vn83gq
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... ri1;i= W
12、说明:日程安排提前五分钟提醒 3+/^
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Bfu/w
13、说明:一条sql 语句搞定数据库分页 RI3GAd
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 3^,p$D<T:,
14、说明:前10条记录 X@Bg_9\i
select top 10 * form table1 where 范围 CklIrD{
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.) d6f T
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) UlMc8 z
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 ANRZQpnXQ
(select a from tableA ) except (select a from tableB) except (select a from tableC) LL_@nvu}M
17、说明:随机取出10条数据 >H,5MM!
select top 10 * from tablename order by newid()
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18、说明:随机选择记录 6ltV}Wt-
select newid() _oE 7<
19、说明:删除重复记录 $YiG0GK<"
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) )agrx76]3w
20、说明:列出数据库里所有的表名 v:gdG|n"
select name from sysobjects where type='U' (XNd]G
21、说明:列出表里的所有的 +[`
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select name from syscolumns where id=object_id('TableName') m^o?{
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22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 9yK\<6}}QH
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type 7P:/ (P
显示结果: 'x,6t66*"l
type vender pcs hiEosI
C
电脑 A 1 5p>rQq0
电脑 A 1 ^8=e8O
光盘 B 2 *pYawT
光盘 A 2 i3vg7V.
手机 B 3 yS.)l
手机 C 3 C'6c,
23、说明:初始化表table1 RN2z/FUf
TRUNCATE TABLE table1 Fu>;hx]s
24、说明:选择从10到15的记录 T[- %b9h>
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc nH}V:C
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三、技巧 XzB3Xs?W2
1、1=1,1=2的使用,在SQL语句组合时用的较多 ]zz%gZz
"where 1=1" 是表示选择全部 "where 1=2"全部不选, _LFABG=
如: i8!err._
if @strWhere !='' 6Z5$cR_vC7
begin TMD*-wYr
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere uBw[|,yn2*
end -FS!v^
else F8&L'@m9>
begin zbJ}@V
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ]Na; b
end Ch)E:Dvq6
我们可以直接写成 : cPV08i
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere fS3%
2、收缩数据库 XCT3:db
--重建索引 J4Ca0Ag
DBCC REINDEX m A('MS2
DBCC INDEXDEFRAG blUS6"kV}
--收缩数据和日志 8:U0M'}u>
DBCC SHRINKDB XO5E-Nh
DBCC SHRINKFILE \Rw^&;\1
3、压缩数据库 \j4!dOGZ
dbcc shrinkdatabase(dbname) k)zBw(wr
4、转移数据库给新用户以已存在用户权限 TVVu_ib
exec sp_change_users_login 'update_one','newname','oldname' D7Y?$=0ycb
go 69 J4p=c,
5、检查备份集 I:WPP'L4o
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' =N2@H5+7
6、修复数据库 qE.3:bQ!`
ALTER DATABASE [dvbbs] SET SINGLE_USER cR/e
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GO Gh}* <X;N
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK hyY^$p+
GO :BF
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ALTER DATABASE [dvbbs] SET MULTI_USER _TyQC1 d
GO r-Oz k$
7、日志清除 w+{{4<+cd
SET NOCOUNT ON bYYjP.rcF
DECLARE @LogicalFileName sysname, .*?)L3n+t
@MaxMinutes INT, ]dT]25V
@NewSize INT (`<B#D;
USE tablename -- 要操作的数据库名 nv3TxG
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Z
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. Ch]q:o4
@NewSize = 1 -- 你想设定的日志文件的大小(M) <bJ~Ol
-- Setup / initialize F.D6O[pZ
DECLARE @OriginalSize int }OSf C~5P
SELECT @OriginalSize = size G+WCE*
FROM sysfiles [OFT!=.y &
WHERE name = @LogicalFileName t&-c?&FO\;
SELECT 'Original Size of ' + db_name() + ' LOG is ' + g`,(O
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + D=)qd@,K
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ie/QSte
FROM sysfiles '.e5Ku
WHERE name = @LogicalFileName {JM3drnw
CREATE TABLE DummyTrans *7qa]i^]
(DummyColumn char (8000) not null) xOZvQ\%
DECLARE @Counter INT, .:/X~{
@StartTime DATETIME, ~]BR(n
@TruncLog VARCHAR(255) )+.AgqxI
SELECT @StartTime = GETDATE(), "WqM<kLa
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' qz 29f
DBCC SHRINKFILE (@LogicalFileName, @NewSize) hDbZ62DDN
EXEC (@TruncLog) ]@qD4:
-- Wrap the log if necessary. [n +(
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired cGWL'r)P
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) {X W>3 "
AND (@OriginalSize * 8 /1024) > @NewSize 7N0m7SC
BEGIN -- Outer loop. &A^2hPe}
SELECT @Counter = 0 3ep
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Koz0Xy
BEGIN -- update ktv{-WG2_
INSERT DummyTrans VALUES ('Fill Log') fVZ_*'v
DELETE DummyTrans >Lz2zlZI
SELECT @Counter = @Counter + 1 pe+m%;nzR
END Ds\f?\Em
EXEC (@TruncLog) aX~'
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END xH-} <7
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 5;9.&f
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + )' 2vUt`_7
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' )Y?E$=M+B
FROM sysfiles ;8gODj:dO
WHERE name = @LogicalFileName +*RpOtss
DROP TABLE DummyTrans +@PZ3
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SET NOCOUNT OFF S1!_ IK$m
8、说明:更改某个表 %;` 3I$
exec sp_changeobjectowner 'tablename','dbo' V{0 V/Nv
9、存储更改全部表 -Q!?=JNtQ
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ezd@>(hJ
@OldOwner as NVARCHAR(128), }Z`@Z'
@NewOwner as NVARCHAR(128) 4;w#mzd
AS _xdttO^N
DECLARE @Name as NVARCHAR(128) B^hK
DECLARE @Owner as NVARCHAR(128) 7p18;Z+6>X
DECLARE @OwnerName as NVARCHAR(128) *kDV ^RBfq
DECLARE curObject CURSOR FOR <pUc(
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select 'Name' = name, j MA%`*r
'Owner' = user_name(uid) _[
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from sysobjects 98WJ"f_ #
where user_name(uid)=@OldOwner <zu)=W'R]
order by name ,-BZsZ0~
OPEN curObject yAc}4*;T/
FETCH NEXT FROM curObject INTO @Name, @Owner UOIZ8Po
WHILE(@@FETCH_STATUS=0) <7X+-%yb;
BEGIN Rh7=,=u
if @Owner=@OldOwner tQ4{:WPG
begin y] ~X{v
set @OwnerName = @OldOwner + '.' + rtrim(@Name) T0}P 'q
exec sp_changeobjectowner @OwnerName, @NewOwner ~0 n9In%
end !i6 aA1'
-- select @name,@NewOwner,@OldOwner ::8E?c
FETCH NEXT FROM curObject INTO @Name, @Owner PvdR)ZEm
END Fw;Y)y=O
close curObject *Xd_=@L&B
deallocate curObject O0"&wvR+5
GO i)e)FhEY6
10、SQL SERVER中直接循环写入数据 O11.wLNH
declare @i int "?sLi
set @i=1 E9[8th,t
while @i<30 nzu
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begin ;:gx;'dm5
insert into test (userid) values(@i) Y'%_--
set @i=@i+1 ^F1zkIE
end mH3{<^Z6
小记存储过程中经常用到的本周,本月,本年函数 fKT(.VNq5
Dateadd(wk,datediff(wk,0,getdate()),-1) GgjBLe=C
Dateadd(wk,datediff(wk,0,getdate()),6) 6d/b*,4[
Dateadd(mm,datediff(mm,0,getdate()),0) VAR/"
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 6UJBE<ntj
Dateadd(yy,datediff(yy,0,getdate()),0) {EupB?
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) iF]vIg#h
上面的SQL代码只是一个时间段 RwwX;I"o%
Dateadd(wk,datediff(wk,0,getdate()),-1) :Zd# }P
Dateadd(wk,datediff(wk,0,getdate()),6) wwmODw<tT
就是表示本周时间段. DSHpM/7
下面的SQL的条件部分,就是查询时间段在本周范围内的: (.3L'+F
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6)
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而在存储过程中 XC{(O:EG
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) }c,}+{q
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) AuYi$?8|5