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。 LX4*3c|i,
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一、基础 g$qNK`y
1、说明:创建数据库 ;P` z
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CREATE DATABASE database-name D6 2xC5
2、说明:删除数据库 OygR5s +
drop database dbname yq3i=RB(
3、说明:备份sql server [V\0P,l
--- 创建 备份数据的 device l s(lL\
USE master %fS__Tb#u
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' /$'R!d5r
--- 开始 备份 |.A#wjF9
BACKUP DATABASE pubs TO testBack cU,]^/0Y
4、说明:创建新表 E~=`Ac,G2
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) =:T pH>f*
根据已有的表创建新表: 6K/j,e>L
A:create table tab_new like tab_old (使用旧表创建新表) P= e3f(M2
B:create table tab_new as select col1,col2... from tab_old definition only =Q % F~
5、说明:删除新表 *c\:ogd
drop table tabname D[.;-4"_
6、说明:增加一个列 {Z>OAR#
Alter table tabname add column col type X 8TwMt
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。 8 |2QJ
7、说明:添加主键: Alter table tabname add primary key(col) ";jj`
说明:删除主键: Alter table tabname drop primary key(col) \r_-gn'1b
8、说明:创建索引:create [unique] index idxname on tabname(col....) O-rHfIxY
删除索引:drop index idxname 99'e)[\
注:索引是不可更改的,想更改必须删除重新建。 29]T:I1d[
9、说明:创建视图:create view viewname as select statement #d+bld \
删除视图:drop view viewname "=7y6bM
10、说明:几个简单的基本的sql语句 xLfx/&2
选择:select * from table1 where 范围 k79"xyXX
插入:insert into table1(field1,field2) values(value1,value2) ogt<vng
删除:delete from table1 where 范围 <NV[8B#k]
更新:update table1 set field1=value1 where 范围 9{gY|2R_
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 6}aIb .j
排序:select * from table1 order by field1,field2 [desc] YT)jBS~&
总数:select count as totalcount from table1 7$ vs X
求和:select sum(field1) as sumvalue from table1 {q9[0-LyJ
平均:select avg(field1) as avgvalue from table1 beLT4~Z=
最大:select max(field1) as maxvalue from table1 |1sl>X,
最小:select min(field1) as minvalue from table1 A}(&At%n4
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11、说明:几个高级查询运算词 mnKSO
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A: UNION 运算符 3h:"-{MW.
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。 0dv# [
B: EXCEPT 运算符 xPFNH`O&
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。 Ga5O&`h
C: INTERSECT 运算符 =(ULfz[:
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。 ]8)nIT^EP
注:使用运算词的几个查询结果行必须是一致的。 &5]&6TD6
12、说明:使用外连接 0n5{Wr$
A、left outer join: B}Q.Is5
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。 @dl{.,J
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 +RXKI{0Km
B:right outer join: /%E X4
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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。 s-V5\Lip,
C:full outer join: 89*txYmx
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。 RAw/Q$I
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二、提升 muMb pF
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ZWZRG-:&H
法一:select * into b from a where 1<>1 5Jo><P a
法二:select top 0 * into b from a /U
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Czj]jA(0f
insert into b(a, b, c) select d,e,f from b; fq-zgqF<
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) K-%x]Fp=
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 3lw
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例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. (;RmfE'PX
4、说明:子查询(表名1:a 表名2:b) "bI'XaSv
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) )%8 ;C]G;
5、说明:显示文章、提交人和最后回复时间 c{YBCWA
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Up:<NHJT
6、说明:外连接查询(表名1:a 表名2:b) 2Zf}t
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c G}!dm0s$
7、说明:在线视图查询(表名1:a ) ~Z74e>V%
select * from (SELECT a,b,c FROM a) T where t.a > 1; 4x.1J
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 PQ6.1}
select * from table1 where time between time1 and time2 W4
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select a,b,c, from table1 where a not between 数值1 and 数值2 p.(8e kh
9、说明:in 的使用方法 H/qv%!/o
select * from table1 where a [not] in ('值1','值2','值4','值6') V`F]L^m=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 C%hMh/Li;
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 4/6?wX
11、说明:四表联查问题: HYd&.*41rE
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 ..... 13+f ^
12、说明:日程安排提前五分钟提醒 1C,=1bY
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 r_8[}|7;
13、说明:一条sql 语句搞定数据库分页 F:p'%#3rU/
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 B=E<</i
14、说明:前10条记录 60
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select top 10 * form table1 where 范围 $yd "bJK
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.) 74Fv9
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 8SV.giG;
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 S;pKL,d>r
(select a from tableA ) except (select a from tableB) except (select a from tableC) 5u(,g1s}UZ
17、说明:随机取出10条数据 <1r#hFUUL
select top 10 * from tablename order by newid() uc>u=kEue
18、说明:随机选择记录 xa7~{ E,
select newid() z?ck*9SZX
19、说明:删除重复记录 l*~ ".q;S
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) M1{ru~Z9
20、说明:列出数据库里所有的表名 '@~\(SH
select name from sysobjects where type='U' \Y37wy4
21、说明:列出表里的所有的 m tPmVze
select name from syscolumns where id=object_id('TableName') woQ UrO(
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。 1N8:,bpsT
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 dvPK5+0W?
显示结果: Wq5 Nc
type vender pcs @xKfqKoqg
电脑 A 1 ]+C;C
电脑 A 1 N0]C?+
光盘 B 2 /z'fFl^6O
光盘 A 2 5somoV B
手机 B 3 ,hMdxZJd
手机 C 3 4z{jWNM)N
23、说明:初始化表table1 a]JQZo1$
TRUNCATE TABLE table1 lCyBdY9n
24、说明:选择从10到15的记录 hUL5V1-j
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ]3u$%vc
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三、技巧 H1!u1k1nl
1、1=1,1=2的使用,在SQL语句组合时用的较多 75>)1H)Xm
"where 1=1" 是表示选择全部 "where 1=2"全部不选, PWavq?SR
如: s{QS2G$5
if @strWhere !='' 0a1Vj56{)
begin e}F1ZJz
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere OrN~ Y#D
end x{GKz#
else l"T{!Oq
begin mA{G:
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' "pa}']7#
end _'CYS3-P3
我们可以直接写成 J5i$D0K[
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere etcpto=Mo
2、收缩数据库 BQ[,(T`+R
--重建索引 &CtWWKS"
DBCC REINDEX `~~.0QC
DBCC INDEXDEFRAG 1[?
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--收缩数据和日志 U};~ff+
DBCC SHRINKDB "Uk "
DBCC SHRINKFILE F.N4Q'2Z
3、压缩数据库 ZvQ~K(3
dbcc shrinkdatabase(dbname) 8y9`xRy
4、转移数据库给新用户以已存在用户权限 Cob<N'.
exec sp_change_users_login 'update_one','newname','oldname' ;%#.d$cU
go 7v{X?86&
5、检查备份集 zB/)_AW
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' N:4oVi@Je
6、修复数据库 P#gY-k&Nr
ALTER DATABASE [dvbbs] SET SINGLE_USER AK$h
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GO [{K
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ( E8(np
GO ZUkrJ'
ALTER DATABASE [dvbbs] SET MULTI_USER e*nT+Rp
GO .u<i<S
7、日志清除 F9N/_H*+
SET NOCOUNT ON mN!5JZ'2
DECLARE @LogicalFileName sysname, MfJs?N0
@MaxMinutes INT, ?3=D-Xrb
@NewSize INT GS<aXhk
USE tablename -- 要操作的数据库名 ~7kIe+V
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 zi7>!#(
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ,JLY
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@NewSize = 1 -- 你想设定的日志文件的大小(M) E#5$O2b#
-- Setup / initialize Rt%3\?rf
DECLARE @OriginalSize int X+R?>xq{=h
SELECT @OriginalSize = size wZAY0@pA
FROM sysfiles "s?!1v(v
WHERE name = @LogicalFileName NWNPq"
SELECT 'Original Size of ' + db_name() + ' LOG is ' + G!%Cc0d"7
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 1cA4-,YO>
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' nVSuvq|S
FROM sysfiles xJ0Q8A
WHERE name = @LogicalFileName l^LYSZg'R8
CREATE TABLE DummyTrans |=\w b^l+
(DummyColumn char (8000) not null) /4Df 'd
DECLARE @Counter INT, ZysZS%
@StartTime DATETIME, PkqOBU*|=
@TruncLog VARCHAR(255) g^`;B"
SELECT @StartTime = GETDATE(), +nLsiC{&
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' RhL!Zz
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Vm3e6Y,K
EXEC (@TruncLog) AV t(e6H
-- Wrap the log if necessary. WNE=|z#|
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Vk3xWD~
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) "Z\^dR
AND (@OriginalSize * 8 /1024) > @NewSize `1 tD&te0
BEGIN -- Outer loop. RD$"ft]Vc
SELECT @Counter = 0 {H\(H_X
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ljS~>&
BEGIN -- update o<J_?7c~}
INSERT DummyTrans VALUES ('Fill Log') |=xK-;qs
DELETE DummyTrans 6wmMg i_m
SELECT @Counter = @Counter + 1 tB,1+I=
END t%B ,ATW
EXEC (@TruncLog) yv2&K=rZp
END =9LeFrz
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Ah|,`0dw
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 8/tvS8I#y
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' L_k'r\L
FROM sysfiles qYwEPGa\
WHERE name = @LogicalFileName O<:"Irq\qr
DROP TABLE DummyTrans [|:kS
SET NOCOUNT OFF ]O\m(of
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8、说明:更改某个表 DbL=2
exec sp_changeobjectowner 'tablename','dbo' XSw!_d
9、存储更改全部表 XAnN<
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch bPe|/wp
@OldOwner as NVARCHAR(128), jRhOo%p
@NewOwner as NVARCHAR(128) cyQ&w>'
AS 52zD!(
DECLARE @Name as NVARCHAR(128) nw)yK%`;M
DECLARE @Owner as NVARCHAR(128) U}=o3u
DECLARE @OwnerName as NVARCHAR(128) M^e;WY@ D
DECLARE curObject CURSOR FOR P:p@Iep
select 'Name' = name, &4m\``//9
'Owner' = user_name(uid) pyf/%9R:d
from sysobjects }uCC~ <^
where user_name(uid)=@OldOwner &idPO{G
order by name j9bn|p$DA
OPEN curObject U|NVDuo{{x
FETCH NEXT FROM curObject INTO @Name, @Owner X}Oo5SNgff
WHILE(@@FETCH_STATUS=0) I Ceb2R
BEGIN R
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if @Owner=@OldOwner NDmTxW#g
begin t/3t69 \x
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 5y1:oiE/
exec sp_changeobjectowner @OwnerName, @NewOwner tbNIl cAWS
end 3~r>G
-- select @name,@NewOwner,@OldOwner {cYS0%Go
FETCH NEXT FROM curObject INTO @Name, @Owner zx(=ArCRr
END 9/@7NNKJ
close curObject 3=)!9;uY
deallocate curObject 8ph*S&H
GO G!^}z(Mgi
10、SQL SERVER中直接循环写入数据 w7;,+Jq
declare @i int .o&Vu,/H
set @i=1 ly8IrgtKy
while @i<30 }kCaTI?@#
begin :M |<c9I
insert into test (userid) values(@i) qZcRK9l]F1
set @i=@i+1 mfI>1W(
end [ITtg?]F
小记存储过程中经常用到的本周,本月,本年函数 R)<PCe`vf
Dateadd(wk,datediff(wk,0,getdate()),-1) HqZ3]
Dateadd(wk,datediff(wk,0,getdate()),6) q#mw#Uw-
Dateadd(mm,datediff(mm,0,getdate()),0) )[c@5zy~*
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ^e1Ux
Dateadd(yy,datediff(yy,0,getdate()),0) (9_O||ee
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ^1b/Y8&8A
上面的SQL代码只是一个时间段 JxV0y
Dateadd(wk,datediff(wk,0,getdate()),-1) m7F"kD
Dateadd(wk,datediff(wk,0,getdate()),6) bH7 lUS~
就是表示本周时间段. o~(/Twxam
下面的SQL的条件部分,就是查询时间段在本周范围内的: \MY`R
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Q.$|TbVfds
而在存储过程中 v'vYNh
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) VY@6!9G
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) l?UFe$9(