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。 `j(+Y
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一、基础 _4W#6!
1、说明:创建数据库 srSTQ\l4
CREATE DATABASE database-name T9$U./69-L
2、说明:删除数据库 kDz.{Ih
drop database dbname UP`q6]P
3、说明:备份sql server $YC~02{
--- 创建 备份数据的 device $e_ps~{7$
USE master Wp]EaYt2D
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' g|zK%tR_P
--- 开始 备份 c[YjGx
BACKUP DATABASE pubs TO testBack zm"\D
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4、说明:创建新表 J{Ay(
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Cn55%:
根据已有的表创建新表: [x)e6p)
A:create table tab_new like tab_old (使用旧表创建新表) OMZT\$9yT
B:create table tab_new as select col1,col2... from tab_old definition only 4tC_W!?$t
5、说明:删除新表 g}D$`Nx:
drop table tabname K@i*Nl
6、说明:增加一个列 0l##M06>
Alter table tabname add column col type aE%VH ;?
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。 H|Nw)*.
7、说明:添加主键: Alter table tabname add primary key(col) "5YdmBy
说明:删除主键: Alter table tabname drop primary key(col) LBE".+
8、说明:创建索引:create [unique] index idxname on tabname(col....) k|_2aQ02
删除索引:drop index idxname "4`%NA
注:索引是不可更改的,想更改必须删除重新建。 G<z)Ydh_
9、说明:创建视图:create view viewname as select statement C1/jA>XW
删除视图:drop view viewname O<3,n;56Z
10、说明:几个简单的基本的sql语句 n=&c5!
选择:select * from table1 where 范围 5;{Bdvcv
插入:insert into table1(field1,field2) values(value1,value2) nT12[@:Tr
删除:delete from table1 where 范围 r#Mx~Zg~
更新:update table1 set field1=value1 where 范围 W<4\4
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 42u\Y_^ID
排序:select * from table1 order by field1,field2 [desc] md`ToU
总数:select count as totalcount from table1 ]/bE${W*]
求和:select sum(field1) as sumvalue from table1 i#lo?\PO>
平均:select avg(field1) as avgvalue from table1 ypd?mw&1}
最大:select max(field1) as maxvalue from table1 4yA`);r62
最小:select min(field1) as minvalue from table1 6+5Catsn
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11、说明:几个高级查询运算词 *p3P\ H^5
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A: UNION 运算符 eTc`FXw`
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 OGFKc#
B: EXCEPT 运算符 !.9vW&t
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 =F&RQ}$
C: INTERSECT 运算符 [*G2wP[$
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。 Fjzk;o
注:使用运算词的几个查询结果行必须是一致的。 @>]3xHE6#=
12、说明:使用外连接 ~D5MAEazS
A、left outer join: `/zt&=`VB
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。 %Let AR
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 2FzS_\":I
B:right outer join: RV`j>1
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。 =M5M;
C:full outer join: P1wRt5
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。 H1nQ.P]_
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二、提升 3\+p1f4
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ~N9-an
法一:select * into b from a where 1<>1 { 9 ".o,
法二:select top 0 * into b from a 0f^.zt{T
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) }L!`K"^O&
insert into b(a, b, c) select d,e,f from b; ^rwSbM$
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) lc-|Q#$3$
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 X t =bc
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. E<uOk
4、说明:子查询(表名1:a 表名2:b) QZr<=}
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) kDq%Y[6Z
5、说明:显示文章、提交人和最后回复时间 3(+#^aw
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b r%pFq1/'!
6、说明:外连接查询(表名1:a 表名2:b) 6t:c]G'J
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 'I]"=O,
7、说明:在线视图查询(表名1:a ) ]5fM?: <l
select * from (SELECT a,b,c FROM a) T where t.a > 1; ts<dUO
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 j\f$r,4
select * from table1 where time between time1 and time2 *]WXM.R8
select a,b,c, from table1 where a not between 数值1 and 数值2 LFyceFbm
9、说明:in 的使用方法 l7,qWSsnK
select * from table1 where a [not] in ('值1','值2','值4','值6') 1`lFF_stkP
10、说明:两张关联表,删除主表中已经在副表中没有的信息 uR@`T18
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Qiw4'xQm
11、说明:四表联查问题: q}$=bR1+
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 ..... 9D{).f0
12、说明:日程安排提前五分钟提醒 f9UaAdJ(
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 wG5RN;`V
13、说明:一条sql 语句搞定数据库分页 kA!(}wRL
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 K<6x4ha
14、说明:前10条记录 ':D&c
select top 10 * form table1 where 范围 1:zu$|%7
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) g@i>R>
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 4D$sFR|?t
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 *\KvcRMGUa
(select a from tableA ) except (select a from tableB) except (select a from tableC) b',bi.FH
17、说明:随机取出10条数据 b0Ov+ )7#
select top 10 * from tablename order by newid() $af}+:'
18、说明:随机选择记录 -!,]Y10
select newid() jHlOP,kc
19、说明:删除重复记录 7/_ VE
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) qYZ7Zt;
20、说明:列出数据库里所有的表名 Q5nyD/k4c
select name from sysobjects where type='U' 3D{4vMmX
21、说明:列出表里的所有的 ^:DhHqvK
select name from syscolumns where id=object_id('TableName') Pmlgh&Z
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 QX.6~*m1
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type %K'*P56
显示结果: m}[~A@qD
type vender pcs N5s|a5
电脑 A 1 /Jf`x>eiH
电脑 A 1 v7FRTrqjj
光盘 B 2 7.
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光盘 A 2 F[D0x26^
手机 B 3 XYHCggy
手机 C 3 M
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23、说明:初始化表table1 ?w37vsN
TRUNCATE TABLE table1 '$h@
24、说明:选择从10到15的记录 D4Y!,7WEVt
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc CKt|c!3 7
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三、技巧 Of7) A
1、1=1,1=2的使用,在SQL语句组合时用的较多 I49l2>
"where 1=1" 是表示选择全部 "where 1=2"全部不选, {L4>2rF
如: t 9n
if @strWhere !='' j22#Bw
begin OZ!$%.?l
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere L\Fu']l
end >9<8G]vcH
else O%K?l}e
begin @=NVOJy}c
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' e*2&s5 #RT
end (Ef2
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我们可以直接写成 B_"OA3d_
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere qIGu#zX W
2、收缩数据库 jUJTcL
--重建索引 U++~3e@l
DBCC REINDEX r` `iC5Ii
DBCC INDEXDEFRAG AqbT{,3yW
--收缩数据和日志 c >
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DBCC SHRINKDB frmqBC VJ:
DBCC SHRINKFILE {8#N7(%z
3、压缩数据库 `+hy#1]
dbcc shrinkdatabase(dbname) Md>f
4、转移数据库给新用户以已存在用户权限 `}9 1S
exec sp_change_users_login 'update_one','newname','oldname' ra%R:xX
go w
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5、检查备份集 ECS<l*i57&
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ,/?%y\:J
6、修复数据库 "T{~,'T
ALTER DATABASE [dvbbs] SET SINGLE_USER adO!Gs9f?
GO I,<>%Z|'
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK \'??
GO Jn[q<e"
ALTER DATABASE [dvbbs] SET MULTI_USER LPapD@Z
GO t}XB|h
7、日志清除 otz_nF;E
SET NOCOUNT ON -?aw^du
DECLARE @LogicalFileName sysname, "zedbJ0
@MaxMinutes INT, k>:/D
@NewSize INT nI*(a:
USE tablename -- 要操作的数据库名 W7*_ T]
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ^3WIl]
@MaxMinutes = 10, -- Limit on time allowed to wrap log. %on9C`/
@NewSize = 1 -- 你想设定的日志文件的大小(M) 9uw,-0*5
-- Setup / initialize hnsa)@
DECLARE @OriginalSize int @0vC v
SELECT @OriginalSize = size Tw`c6^%^y
FROM sysfiles iM/*&O}
WHERE name = @LogicalFileName tB ,.
SELECT 'Original Size of ' + db_name() + ' LOG is ' + g]Xzio&w
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + d4p{5F7]^
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ^A11h6I
FROM sysfiles u+z .J4w
WHERE name = @LogicalFileName K=m9H=IX~T
CREATE TABLE DummyTrans q!hy;K`Jd
(DummyColumn char (8000) not null) ''(fH$pY
DECLARE @Counter INT, 84p[N8
@StartTime DATETIME, $kkp*3{ot
@TruncLog VARCHAR(255) |D;"D
SELECT @StartTime = GETDATE(), ZSF=
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Q(=Vk~v
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 8K@"B
EXEC (@TruncLog) B:3+',i1
-- Wrap the log if necessary. xm}q6>jRV
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired vbRrk($`
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) (>rS
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AND (@OriginalSize * 8 /1024) > @NewSize wRXn9
BEGIN -- Outer loop. t<!+b@l5
SELECT @Counter = 0 b`h%W"|2L
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ]]J#7L#
BEGIN -- update h/ LR+XX!
INSERT DummyTrans VALUES ('Fill Log') iot.E%G
DELETE DummyTrans RwAbIXG{0
SELECT @Counter = @Counter + 1 Yg=E@F
END Z:_m}Ya|
EXEC (@TruncLog) ]RH=s7L
END ><;l:RGK|
SELECT 'Final Size of ' + db_name() + ' LOG is ' + `ICcaRIN8I
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + _HWHQF7
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' L4YVH2`0)
FROM sysfiles JCw{ ?^F"
WHERE name = @LogicalFileName #<a_: m)@
DROP TABLE DummyTrans |5oKq'(b
SET NOCOUNT OFF {yvb$ND|j{
8、说明:更改某个表 Y!++CMzU
exec sp_changeobjectowner 'tablename','dbo' QL)>/%yU
9、存储更改全部表 1DEO3p
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch <a8#0ojm
@OldOwner as NVARCHAR(128), WF ?/GN
@NewOwner as NVARCHAR(128) O`wYMng)
AS qDby!^ryc
DECLARE @Name as NVARCHAR(128) a.
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DECLARE @Owner as NVARCHAR(128) S2J#b"Y
DECLARE @OwnerName as NVARCHAR(128) CrnB{Z4L
DECLARE curObject CURSOR FOR G$;>ueM
select 'Name' = name, g2g`,"T
'Owner' = user_name(uid) X'V+^u@W
from sysobjects hlAR[ ]
where user_name(uid)=@OldOwner N<KKY"?I'
order by name {PN:bb
OPEN curObject `4VO&lRm
FETCH NEXT FROM curObject INTO @Name, @Owner BN+V,W
WHILE(@@FETCH_STATUS=0) !Oeq
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BEGIN La`h$=#`
if @Owner=@OldOwner <A#5v\{.;~
begin G_V.H\w
set @OwnerName = @OldOwner + '.' + rtrim(@Name) uz*d^gr}
exec sp_changeobjectowner @OwnerName, @NewOwner E4Y"X
end #V<`U:.
-- select @name,@NewOwner,@OldOwner n_<mPU
FETCH NEXT FROM curObject INTO @Name, @Owner HA$Y1}
END r#LnDseW
close curObject HzP.aw4
deallocate curObject sW;7m[o
GO rs[?v*R74
10、SQL SERVER中直接循环写入数据 EKcC+g
declare @i int %
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set @i=1 "Jb3&qdU
while @i<30 ~k9O5S{
begin V-[2jC{
insert into test (userid) values(@i) ^[ET&"
set @i=@i+1 q&u$0XmV
end qovQ9O
小记存储过程中经常用到的本周,本月,本年函数 $ I#7dJ"*
Dateadd(wk,datediff(wk,0,getdate()),-1) `Jn,IDq
Dateadd(wk,datediff(wk,0,getdate()),6) M6# \na
Dateadd(mm,datediff(mm,0,getdate()),0) 'b8R#R\P
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) KuA>"X
Dateadd(yy,datediff(yy,0,getdate()),0) `koOp
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) |}Q( F+cL
上面的SQL代码只是一个时间段 Af`z/:0<
Dateadd(wk,datediff(wk,0,getdate()),-1) f.@Xjf
Dateadd(wk,datediff(wk,0,getdate()),6) BRe{1i 6
就是表示本周时间段. SEYG y+#K
下面的SQL的条件部分,就是查询时间段在本周范围内的: >OT\~C
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) LRWOBD
而在存储过程中 5!<o-{J[(=
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Ymq3ty]Pe
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) S2ark,sp6