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。 #bCzWg
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一、基础 Azag*M?
1、说明:创建数据库 G[s/M\l
CREATE DATABASE database-name 4{#0ci{
2、说明:删除数据库 -|(
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drop database dbname Vh8RVFi;c
3、说明:备份sql server ](SqLTB+?
--- 创建 备份数据的 device (tzfyZ M
USE master GpGq' 8|(
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ^k4 n
--- 开始 备份 O+PRP"$g"
BACKUP DATABASE pubs TO testBack }080=E
4、说明:创建新表 F?hGt]o
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 2/RW( U
根据已有的表创建新表: !Tu4V\^~A
A:create table tab_new like tab_old (使用旧表创建新表) 'OvyQ/T
B:create table tab_new as select col1,col2... from tab_old definition only ^/"2s}+
5、说明:删除新表 3TF'[(K=
drop table tabname W0s3nio
6、说明:增加一个列 p^U#1c
Alter table tabname add column col type aT}?-CUxx
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 _v +At;Y
7、说明:添加主键: Alter table tabname add primary key(col) a.B<W9$`
说明:删除主键: Alter table tabname drop primary key(col) {z*`*
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8、说明:创建索引:create [unique] index idxname on tabname(col....) 8Lh[>|~=
删除索引:drop index idxname &d&nsQ
注:索引是不可更改的,想更改必须删除重新建。 N7}yU~j^
9、说明:创建视图:create view viewname as select statement W=zp:6Z~
删除视图:drop view viewname dY'>'1>P
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10、说明:几个简单的基本的sql语句 WkSv@Y,
选择:select * from table1 where 范围 eN-lz_..7
插入:insert into table1(field1,field2) values(value1,value2) R\:t
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删除:delete from table1 where 范围 t2#zQ[~X!
更新:update table1 set field1=value1 where 范围 A=l1_8,`h
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! SS"Z>talw
排序:select * from table1 order by field1,field2 [desc] `fUPq
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总数:select count as totalcount from table1 N3o
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求和:select sum(field1) as sumvalue from table1 W;ADc2#)
平均:select avg(field1) as avgvalue from table1 %\?Gzc_
最大:select max(field1) as maxvalue from table1 q a}=p
最小:select min(field1) as minvalue from table1 ~)%DiGW&
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11、说明:几个高级查询运算词 .R{+Pz D
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A: UNION 运算符 T(iL#2^
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。 axLO: Q,
B: EXCEPT 运算符 avEsX_.
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。 !)h?2#V8;
C: INTERSECT 运算符 "MU)8$d
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 .8/W_iC92
注:使用运算词的几个查询结果行必须是一致的。 /<it2=
12、说明:使用外连接 AW/)R"+
A、left outer join: "7_qB8\
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 SCKpW#2dP{
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c hsHtLH+@
B:right outer join: n8 e4`-cY
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 *tL1t\jY
C:full outer join: +<W8kb
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 ]-tAgNzl%
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二、提升 jS'hs>Ot
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) FN29 5:Iuw
法一:select * into b from a where 1<>1 P<s:dH"
法二:select top 0 * into b from a V9<CeTl'
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) (]*!`(_b
insert into b(a, b, c) select d,e,f from b; ?%RR+(2m
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) 4&'_~ qU
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Q2K)Nl >_
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 31n|ScXv
4、说明:子查询(表名1:a 表名2:b) eKek~U&
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) }*3#*y "
5、说明:显示文章、提交人和最后回复时间 a#i%7mfn
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ?*A"#0
6、说明:外连接查询(表名1:a 表名2:b) 7T@"2WYat
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ~AG."<}
7、说明:在线视图查询(表名1:a ) u@$pOLI
select * from (SELECT a,b,c FROM a) T where t.a > 1; W5a>6u=g,
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 TM?7F2
select * from table1 where time between time1 and time2 i"U<=~
select a,b,c, from table1 where a not between 数值1 and 数值2 XIJ{qrDr
9、说明:in 的使用方法 |4u?Q+k%%
select * from table1 where a [not] in ('值1','值2','值4','值6') .Wq"
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ~L=Idt!9
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) jj*e.t:F
11、说明:四表联查问题: M}W};~V2ng
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 ..... tx{tIw^2;
12、说明:日程安排提前五分钟提醒 DsH`I%w{
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 `-[+(+["
13、说明:一条sql 语句搞定数据库分页 8GFA}_(^R
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 ZeYkZzN
14、说明:前10条记录 sKuPV
select top 10 * form table1 where 范围 1q(o3%
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.) b=j]tb,
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) O.~@V(7ah
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 d*TpHLm
(select a from tableA ) except (select a from tableB) except (select a from tableC) SK_i 3?
17、说明:随机取出10条数据 NK0hT,_
select top 10 * from tablename order by newid() A1nEp0%Y
18、说明:随机选择记录 yyVv@
select newid() {ei,>5K
19、说明:删除重复记录 w=S7zzL)
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) (Jb[_d*
20、说明:列出数据库里所有的表名 8ncgTCH:
select name from sysobjects where type='U' t?R=a- ZI
21、说明:列出表里的所有的 "7tEk<x
select name from syscolumns where id=object_id('TableName') i&dMX:fRd
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。 %*wOJx
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 =\l7k<
显示结果: ;
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type vender pcs o4g<[X)
电脑 A 1 Uv"GG:
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电脑 A 1 MOEB{~v`;
光盘 B 2 HJ,sZ4*]]
光盘 A 2 9p5{,9 .3*
手机 B 3 =#c?g Wb56
手机 C 3 >4} 2~;
23、说明:初始化表table1 WxFrqUz
TRUNCATE TABLE table1 <r{ )*]#l
24、说明:选择从10到15的记录 k(v8zDq*
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc * 5Y.9g3)Q
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三、技巧 P"WnU'+
1、1=1,1=2的使用,在SQL语句组合时用的较多 h.W;Dmf6]
"where 1=1" 是表示选择全部 "where 1=2"全部不选, Aa;s.:?
如: d.3O1TXK
if @strWhere !='' 'ehJr/0&g
begin ,3{z_Rax-
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Rtl;*ZAS
end %Pb 5PIk4
else bUp
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begin ?>p<!:E!r
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' r&|-6OQZZ
end VIxt;yE
我们可以直接写成 kGZ_/"iuO
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere (]mh}=:KDg
2、收缩数据库 K$..#]\TM
--重建索引 vZns,K#4H\
DBCC REINDEX U-#t&yjh#
DBCC INDEXDEFRAG O}!L;?
--收缩数据和日志
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DBCC SHRINKDB 3=r8kh7,
DBCC SHRINKFILE n_n0Q}du
3、压缩数据库 aQEMCWxZ
dbcc shrinkdatabase(dbname) J0U9zI4
4、转移数据库给新用户以已存在用户权限 @lP<Mq~]
exec sp_change_users_login 'update_one','newname','oldname' [[P UK{P0
go ReCmv/AE
5、检查备份集 d&p]O
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' !m#cneV
6、修复数据库 'sL>U$(
ALTER DATABASE [dvbbs] SET SINGLE_USER $z+iB;x
GO [z:bnS~yiD
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 1;l&ck-Gg/
GO ZL`G<Mo;.
ALTER DATABASE [dvbbs] SET MULTI_USER A2b
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GO !t["pr\
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7、日志清除 h
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SET NOCOUNT ON 6SMGXy*]^
DECLARE @LogicalFileName sysname, e_wz8]K)n
@MaxMinutes INT, o4b!U %
@NewSize INT ogX'3L
USE tablename -- 要操作的数据库名 Oifu ?f<r
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 X"W%(x`w
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 'wAOY
@NewSize = 1 -- 你想设定的日志文件的大小(M) =$g8"[4
-- Setup / initialize nzTzc5
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DECLARE @OriginalSize int 9_rNJLj8y
SELECT @OriginalSize = size 8E /]k\
FROM sysfiles )T:{(v7 d`
WHERE name = @LogicalFileName ]rDf3_!m(
SELECT 'Original Size of ' + db_name() + ' LOG is ' + &DFe+y~PR
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + $;_'5`xs
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' S#X$QD
FROM sysfiles 2oAPJUPOJ
WHERE name = @LogicalFileName daaEN(
CREATE TABLE DummyTrans QY2!.a^q
(DummyColumn char (8000) not null) <=V2~
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DECLARE @Counter INT, KLXv?4!
@StartTime DATETIME, '!!w|kd
@TruncLog VARCHAR(255) *_$%Tv.]
SELECT @StartTime = GETDATE(), u!%]?MSc
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' I'o9.B8%#
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ?kew[oZ
EXEC (@TruncLog) 5( lE$&
-- Wrap the log if necessary. 9jiZtwRpk
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 1{% EQhNd
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ,LXuU8sB
AND (@OriginalSize * 8 /1024) > @NewSize &tKs
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BEGIN -- Outer loop. +b]g;
SELECT @Counter = 0 6:B[8otQ
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) cW,wN~
BEGIN -- update *&B*/HAN
INSERT DummyTrans VALUES ('Fill Log') x!q$`zF\\
DELETE DummyTrans ,SJB3if
SELECT @Counter = @Counter + 1 g?M\Z";
END ^" ywltW>
EXEC (@TruncLog) $.(>Sj1
END O@3EJkv
SELECT 'Final Size of ' + db_name() + ' LOG is ' + UUv&X+Y
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + @3[Z QF
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' v I]|
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FROM sysfiles r]km1SrS
WHERE name = @LogicalFileName PDX^MYoN
DROP TABLE DummyTrans O!sZMGF$p
SET NOCOUNT OFF .*D~ .!
8、说明:更改某个表 E/ (:\Cm^
exec sp_changeobjectowner 'tablename','dbo' /Z>#lMg\.
9、存储更改全部表 :9c
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch KEsMes(*
@OldOwner as NVARCHAR(128), ~,Q+E8
@NewOwner as NVARCHAR(128) K(Otgp+zb
AS C$)#s{*
DECLARE @Name as NVARCHAR(128) !l_1r$
DECLARE @Owner as NVARCHAR(128) A75IG4]
DECLARE @OwnerName as NVARCHAR(128) p[&'*"o!/
DECLARE curObject CURSOR FOR IQdiVj
select 'Name' = name, D<}KTyG]
'Owner' = user_name(uid) v 4(!~S
from sysobjects Gw3|"14
where user_name(uid)=@OldOwner Qm,|'y:Tg
order by name Rs8`M8(4%
OPEN curObject Ol"p^sqwj
FETCH NEXT FROM curObject INTO @Name, @Owner vN7a)s
WHILE(@@FETCH_STATUS=0) .0#?u1gXsX
BEGIN B4GgR,P@S
if @Owner=@OldOwner 6+FmYp
begin mN_RB{g{
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 1I KDp]SN
exec sp_changeobjectowner @OwnerName, @NewOwner A;w,m{9<
end Tm[IOuhM'?
-- select @name,@NewOwner,@OldOwner X'ryfa1|
FETCH NEXT FROM curObject INTO @Name, @Owner ,jbj-b(
END eqs.zL
close curObject d/- f]
deallocate curObject <<v,9*h
GO +=Crfvt
10、SQL SERVER中直接循环写入数据 z)q9O_g9
declare @i int Q9X_aB0
set @i=1 GKtG#jZ&
while @i<30 sBq @W4
begin qJVW :$1q
insert into test (userid) values(@i) <"AP&J'H
set @i=@i+1 J^ryUOo}b
end 4'?kyTO~
小记存储过程中经常用到的本周,本月,本年函数 Fc7mAV=
Dateadd(wk,datediff(wk,0,getdate()),-1) pb}QP
Dateadd(wk,datediff(wk,0,getdate()),6) e!ar:>T
Dateadd(mm,datediff(mm,0,getdate()),0) !u~( \Rb;
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Yc /rjEn7O
Dateadd(yy,datediff(yy,0,getdate()),0) hPx=3L$
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Cz
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上面的SQL代码只是一个时间段 me$7\B;wy
Dateadd(wk,datediff(wk,0,getdate()),-1) yFshV\
Dateadd(wk,datediff(wk,0,getdate()),6) -O\!IXG^
就是表示本周时间段. a*NcL(OC
下面的SQL的条件部分,就是查询时间段在本周范围内的: XJC|6"n
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) PR{?l
而在存储过程中 &voyEvX/S
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) wvcG <sj
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ; @-7'%(C