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。 a61?G!]
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一、基础 KvEZbf3f
1、说明:创建数据库 mZ.E;X& ,*
CREATE DATABASE database-name t`0(5v
2、说明:删除数据库 ^ |>)H
drop database dbname 30h1)nQ$h}
3、说明:备份sql server R[2h!.O8
--- 创建 备份数据的 device yjucR
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USE master 9-?kamA
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' HgRfMiC
--- 开始 备份 ]2xoeNF/W{
BACKUP DATABASE pubs TO testBack {N0ky=ud
4、说明:创建新表 cWa>rUsF
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) cx4'rK.
根据已有的表创建新表: 1F?ylZ|~
A:create table tab_new like tab_old (使用旧表创建新表) 8;P_KRaE
B:create table tab_new as select col1,col2... from tab_old definition only _1?Fyu&<5
5、说明:删除新表 W97
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drop table tabname r<.*:]L
6、说明:增加一个列 =_d-MJy~6
Alter table tabname add column col type mW U*}-M
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 0Y\7A
7、说明:添加主键: Alter table tabname add primary key(col) =Y5*J#
说明:删除主键: Alter table tabname drop primary key(col) tA9(N>[*
8、说明:创建索引:create [unique] index idxname on tabname(col....) 1;9 %L@
删除索引:drop index idxname CYC6:g|)
注:索引是不可更改的,想更改必须删除重新建。 4JjO.H
9、说明:创建视图:create view viewname as select statement qzu%Pp6If
删除视图:drop view viewname }u'O<d~z?
10、说明:几个简单的基本的sql语句 l7GLN1#m
选择:select * from table1 where 范围 ^i~'aq
插入:insert into table1(field1,field2) values(value1,value2) (9D,Ukw
删除:delete from table1 where 范围 <*&2b
更新:update table1 set field1=value1 where 范围 cWL7gv\|
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! _xXDvBU
排序:select * from table1 order by field1,field2 [desc] FZtILlw
总数:select count as totalcount from table1 W$Zc;KRz$0
求和:select sum(field1) as sumvalue from table1 As*59jkB
平均:select avg(field1) as avgvalue from table1 V~qlg1h
最大:select max(field1) as maxvalue from table1 s)|l-I
最小:select min(field1) as minvalue from table1 O:G-I$F|
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11、说明:几个高级查询运算词 7ip(-0
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A: UNION 运算符 &:*|K xX
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。 ?\Z-3l%M
B: EXCEPT 运算符
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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。 %+Khj@aX
C: INTERSECT 运算符 4U1"F 7'
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。 {piZm12q?
注:使用运算词的几个查询结果行必须是一致的。 kzb1iBe 6m
12、说明:使用外连接 b."1p7'
A、left outer join: We,~P\g
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。 jR&AQ-H&
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 qbe9 CF'@_
B:right outer join: c6)q(zz
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。 sp$W=Wu7
C:full outer join: awa$o
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。 >P\/\xL=
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二、提升 tvG/oe .1'
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) FqK2[]8
法一:select * into b from a where 1<>1 +Udlt)H
法二:select top 0 * into b from a L`{EXn[
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) BpKgUwf;C
insert into b(a, b, c) select d,e,f from b; A PR%ZpG
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) 6?c(ue iL[
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 I~>L4~g)
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. h47l;`kD-#
4、说明:子查询(表名1:a 表名2:b) #0j,1NpL
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) xN#. Pm~
5、说明:显示文章、提交人和最后回复时间 B]YY[i
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b $?u ^hMU=
6、说明:外连接查询(表名1:a 表名2:b) i
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Ka\%kB>*`
7、说明:在线视图查询(表名1:a ) SggS8$a`
select * from (SELECT a,b,c FROM a) T where t.a > 1; fX2PteA0qX
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 S?_ ;$Cn
select * from table1 where time between time1 and time2 3QrYH
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select a,b,c, from table1 where a not between 数值1 and 数值2 X pd^^
9、说明:in 的使用方法 U ]6Hml;l
select * from table1 where a [not] in ('值1','值2','值4','值6') yegTKoY
10、说明:两张关联表,删除主表中已经在副表中没有的信息 B[0XzV]Z
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) %%w]-`^h,
11、说明:四表联查问题: 3q.O^`y FU
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 ..... L_YVe(dT
12、说明:日程安排提前五分钟提醒 >2l;KVm%
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 cEd!t6Z
13、说明:一条sql 语句搞定数据库分页 ]='E&=nc
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 {<- BU[H
14、说明:前10条记录 O5Xu(q5+
select top 10 * form table1 where 范围 {^#62Y
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.) x1kb]0s<-
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) DN@T4!
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 $Y4;Xe=
(select a from tableA ) except (select a from tableB) except (select a from tableC) )5j%."
17、说明:随机取出10条数据 mSzBNvci
select top 10 * from tablename order by newid() }X3SjNd q
18、说明:随机选择记录 vO2 o/
select newid() ?q<"!U|e
19、说明:删除重复记录 A8R}W=
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) dSb|hA}@
20、说明:列出数据库里所有的表名 [$Ld>`3
select name from sysobjects where type='U' }I'g@Pw9[
21、说明:列出表里的所有的 (SLAq$gvd
select name from syscolumns where id=object_id('TableName') ~o+HAc`=v
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 lc=C
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type DT@6Q.
显示结果: \@4_l?M
type vender pcs 5"5D(
电脑 A 1 8uX1('+T*
电脑 A 1 B;?"R
光盘 B 2 (Ia} ]q
光盘 A 2 iG*/m><-
手机 B 3 r c7"sIkV
手机 C 3 qlSc[nEk
23、说明:初始化表table1 DH_Mll>
TRUNCATE TABLE table1 Vet7a_
24、说明:选择从10到15的记录 u5EHzoq
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc
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三、技巧 g`!:7|&,_
1、1=1,1=2的使用,在SQL语句组合时用的较多 {@9y%lmrh
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 0=;jGh}|i
如: ++:v O
if @strWhere !='' B8_w3;x
begin 5[M?O4mi
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Ak$ghb
end V$+xJ m
else z.:{
begin JI}(R4uV
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Wr7^
end a'ViyTBo
我们可以直接写成 F
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere K^k1]!W=
2、收缩数据库 h@T}WZv
--重建索引 7{:| )
DBCC REINDEX l'(Cxhf.W
DBCC INDEXDEFRAG {b>tX)Tep
--收缩数据和日志 Te~"\`omJ3
DBCC SHRINKDB a$g4)0eS
DBCC SHRINKFILE d(w
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3、压缩数据库 u7&r'rZ1_!
dbcc shrinkdatabase(dbname) U6"U^
4、转移数据库给新用户以已存在用户权限 c@:r\]
exec sp_change_users_login 'update_one','newname','oldname' LF0gy3
go sD.bBz
5、检查备份集 I -i)D
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' })Rmu."\
6、修复数据库 Roy0?6O
ALTER DATABASE [dvbbs] SET SINGLE_USER O k_I}X
GO qu8i Jq
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK REhXW_x
GO 2"NRnCx*
ALTER DATABASE [dvbbs] SET MULTI_USER SHPaSq'&N
GO Rs:<'A
7、日志清除 G.O0*E2V
SET NOCOUNT ON 0,(U_+n
DECLARE @LogicalFileName sysname, rB}UFS)
@MaxMinutes INT, Gu<3*@Ng
@NewSize INT I~MBR2$9
USE tablename -- 要操作的数据库名 yE-&TW_q:>
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 hZ.Sj~>7`
@MaxMinutes = 10, -- Limit on time allowed to wrap log. _Q/D%7[pa
@NewSize = 1 -- 你想设定的日志文件的大小(M) j_\sdH*r
-- Setup / initialize kqSCKY1
DECLARE @OriginalSize int {!xPq%
SELECT @OriginalSize = size |,5b[Y"Dt
FROM sysfiles 4-=> >#
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WHERE name = @LogicalFileName er^z:1'
SELECT 'Original Size of ' + db_name() + ' LOG is ' + X",fp
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + %WCA?W0:4
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' tuK"}HepB
FROM sysfiles =R!=uml(
WHERE name = @LogicalFileName t/_w}
CREATE TABLE DummyTrans -c%GlpZw
(DummyColumn char (8000) not null) UKQ,]VC
DECLARE @Counter INT, f!*b8ND^R
@StartTime DATETIME, T.!GEUQ
@TruncLog VARCHAR(255) M'W@K
SELECT @StartTime = GETDATE(), Q$W0>bUP
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' R,/?p
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ()K%Rn
EXEC (@TruncLog) =lS~2C
-- Wrap the log if necessary. '+Dn~8Y+9
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired FJv=5L
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) &7T0nB/)
AND (@OriginalSize * 8 /1024) > @NewSize ._=Pa)T
BEGIN -- Outer loop. 6
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SELECT @Counter = 0 :HRJ49a
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) XY1NTo.=
BEGIN -- update ${KDGJ,^
INSERT DummyTrans VALUES ('Fill Log') *(s+u~, I
DELETE DummyTrans Q<d\K(<3?:
SELECT @Counter = @Counter + 1 4*lShkL
END ,|"tLN*m
EXEC (@TruncLog) T^aEx.`O}`
END +XJj:%yt
SELECT 'Final Size of ' + db_name() + ' LOG is ' + u=jF\W9
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + CY0|.x
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' $B*E k>EK
FROM sysfiles RqXcL,,9
WHERE name = @LogicalFileName vd SV6p.d
DROP TABLE DummyTrans 4<70mUnt
SET NOCOUNT OFF 5P
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8、说明:更改某个表 U{RW=sYB~9
exec sp_changeobjectowner 'tablename','dbo' S,lJ&Rsu
9、存储更改全部表 3otia;&B
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch $/5Jc[Ow
@OldOwner as NVARCHAR(128), yVUA7IY
@NewOwner as NVARCHAR(128) `z-4OJ8~
AS ,JN2q]QPP
DECLARE @Name as NVARCHAR(128) fg%I?ou
DECLARE @Owner as NVARCHAR(128) "QA#
DECLARE @OwnerName as NVARCHAR(128) kW4/0PD
DECLARE curObject CURSOR FOR X(?.*m@+TB
select 'Name' = name, d[w 'j/{
'Owner' = user_name(uid) B1JdkL 3h
from sysobjects 0lF[N.!\9
where user_name(uid)=@OldOwner 5 r"`c
order by name 0MF[e3)a
OPEN curObject .Hl]xI$;+
FETCH NEXT FROM curObject INTO @Name, @Owner -B9C2
WHILE(@@FETCH_STATUS=0) mgL~ $
BEGIN #c'yAa
if @Owner=@OldOwner F5gL-\6
begin ?7@B$OlU
set @OwnerName = @OldOwner + '.' + rtrim(@Name) j =r`[Bm
exec sp_changeobjectowner @OwnerName, @NewOwner o
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end 8V;@yzIha
-- select @name,@NewOwner,@OldOwner {tV)+T
FETCH NEXT FROM curObject INTO @Name, @Owner _jR%o1Y}
END dfiA- h
close curObject A$WE:<^
deallocate curObject {^Vkxf]
GO BP,"vq $'+
10、SQL SERVER中直接循环写入数据 [95(%&k.Q
declare @i int PSI5$Vna4p
set @i=1 wRgmw
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while @i<30 -f#0$Z/0
begin "8&pT^
insert into test (userid) values(@i) 7!#x-KR~5
set @i=@i+1 "nU5c4
end efy65+~GG
小记存储过程中经常用到的本周,本月,本年函数 >zFe)
Dateadd(wk,datediff(wk,0,getdate()),-1) `g<@F^x5
Dateadd(wk,datediff(wk,0,getdate()),6) 7u6o~(
Dateadd(mm,datediff(mm,0,getdate()),0) Ha1E /b]K
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) "2i{ L '
Dateadd(yy,datediff(yy,0,getdate()),0) YxlV2hcX;
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) EQSOEf[
上面的SQL代码只是一个时间段 ,@tkL!"9q
Dateadd(wk,datediff(wk,0,getdate()),-1) 5:Pp62
Dateadd(wk,datediff(wk,0,getdate()),6) <h4"^9hL
就是表示本周时间段. $]%;u: Sa
下面的SQL的条件部分,就是查询时间段在本周范围内的: /WRS6n
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 2BXpk^d5y
而在存储过程中 z~L''X7g
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Al09R,I;
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) C$vKRg\o