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。 FCmS3KIa,
!$5U\"M
VuW&CnZ
一、基础 (5N&bh`E
1、说明:创建数据库 %lPFq-
CREATE DATABASE database-name {Z|.-~W
2、说明:删除数据库 s.I=H^T
drop database dbname f;%4O'
3、说明:备份sql server m[u
6<C
--- 创建 备份数据的 device
S,v9\wN.
USE master NC2PW+(
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' `ml;#n,*
--- 开始 备份 O@_)]z?jUc
BACKUP DATABASE pubs TO testBack sOW-GWSE<
4、说明:创建新表
FyQ^@@
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) )P.|Xk:r
根据已有的表创建新表: B|~\m~
A:create table tab_new like tab_old (使用旧表创建新表) D`.CXFI+U
B:create table tab_new as select col1,col2... from tab_old definition only Efw/bTEg
5、说明:删除新表 |xaA3UA
drop table tabname o0Hh&:6!M
6、说明:增加一个列 L+QEFQ:r5
Alter table tabname add column col type $y> J=
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。 r jL%M';
7、说明:添加主键: Alter table tabname add primary key(col) U07n7`2w
说明:删除主键: Alter table tabname drop primary key(col) d=wzN3 ;-
8、说明:创建索引:create [unique] index idxname on tabname(col....) ^fb4g+Au
删除索引:drop index idxname Fk
1M5Dm
注:索引是不可更改的,想更改必须删除重新建。 TaB35glLY
9、说明:创建视图:create view viewname as select statement ?Zoq|Q+
删除视图:drop view viewname (N43?iv(
10、说明:几个简单的基本的sql语句 H1=R(+-s
选择:select * from table1 where 范围 uBs[[9je(
插入:insert into table1(field1,field2) values(value1,value2) ~GS`@IU}
删除:delete from table1 where 范围
Px K
更新:update table1 set field1=value1 where 范围 {{=7 mbc
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! QkzPzbF"
排序:select * from table1 order by field1,field2 [desc] `&>!a
总数:select count as totalcount from table1 YrgwR
求和:select sum(field1) as sumvalue from table1 G0//P
.#
平均:select avg(field1) as avgvalue from table1 z0Gh |N@)
最大:select max(field1) as maxvalue from table1 diqG8KaK
最小:select min(field1) as minvalue from table1 Qo{^jDe,c*
W?/7PVGv5h
AC(}cMM+
s6). ?oE
11、说明:几个高级查询运算词 $-
#M~eZv
"$:nz}
^ tm,gh
A: UNION 运算符 e v?Hz8Q;(
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。 ({zp$P}
B: EXCEPT 运算符 ;nv4lxm
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 :ZU
C: INTERSECT 运算符 z/rN+ ,
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 #!y|cP~;I
注:使用运算词的几个查询结果行必须是一致的。 P67r+P,
12、说明:使用外连接 +V7*vlx-
A、left outer join: FAU^(]-5m
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 ;Z.}~d6>!
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c F+L q
B:right outer join: g >-iBxml
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 F=^vu7rf
C:full outer join: zYSXG-k
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 haa[ob6T
Vv=d*
?~S\^4]
二、提升 h.~S^uKi*
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) F K={%
法一:select * into b from a where 1<>1 S)$ES6]9/
法二:select top 0 * into b from a |TEf? <"c
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) I%*o7"
insert into b(a, b, c) select d,e,f from b; +5);"71
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) ;Cyt2]F
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 w>VM--
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. UwdcU^xt9
4、说明:子查询(表名1:a 表名2:b)
D[]vJ
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) oOe5IczS(
5、说明:显示文章、提交人和最后回复时间 {My/+{eS!?
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b r"U$udwjg
6、说明:外连接查询(表名1:a 表名2:b) |$9k
z31
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Dw6Q2Gnv
7、说明:在线视图查询(表名1:a ) 31YzTbl[H
select * from (SELECT a,b,c FROM a) T where t.a > 1; le|e 4f*+
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 d%4!d_I<
select * from table1 where time between time1 and time2 HHoh//(\
select a,b,c, from table1 where a not between 数值1 and 数值2 Z:9"7^+
9、说明:in 的使用方法 WRFzb0;01
select * from table1 where a [not] in ('值1','值2','值4','值6') W/{HZ< :.
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&ZN\@0X
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) o $p*C
11、说明:四表联查问题: {b+!0[
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... ](-:l6
12、说明:日程安排提前五分钟提醒 P*R`3Y,
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 \\x``*
13、说明:一条sql 语句搞定数据库分页 +~02j1Jx
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 01#a
14、说明:前10条记录 =?T'@C
select top 10 * form table1 where 范围 @;d(>_n
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) aLuxCobV
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) aeE9dV~
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 T3)/?f?|
(select a from tableA ) except (select a from tableB) except (select a from tableC) ^^)D!I"cA,
17、说明:随机取出10条数据 J0lTp /
select top 10 * from tablename order by newid() =JNoC01D
18、说明:随机选择记录 qV^,muyoG
select newid() @y)-!MHN(8
19、说明:删除重复记录 ~n|*-rca
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) eH=lX9
20、说明:列出数据库里所有的表名 3MiNJi#=2
select name from sysobjects where type='U' f#/v^Ql*
21、说明:列出表里的所有的 +vBq,'k`
select name from syscolumns where id=object_id('TableName') fkyj&M/
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 hU+sg~E
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type !1)lGjMW
显示结果: Sep}{`u
type vender pcs 4 K{4=uU
电脑 A 1 3(}HD*{E[@
电脑 A 1 ;VYL7Xu](
光盘 B 2 % nP13V]
光盘 A 2 xAQ=oF
+
手机 B 3 LYkW2h`JQ
手机 C 3 *w59BO&M4
23、说明:初始化表table1 0b~5i-zM/
TRUNCATE TABLE table1 SpjL\ p0
24、说明:选择从10到15的记录 zpiqJEf|'"
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc &T}~h^/t
avykg(
ft4J.oT
=?0o5|u]
三、技巧 \qi=Us|=
1、1=1,1=2的使用,在SQL语句组合时用的较多 xv9SQ,n<
"where 1=1" 是表示选择全部 "where 1=2"全部不选, XNf%vC>
如: k P>G4$e_v
if @strWhere !='' X@5!I+u\L
begin XQ%*U=)s
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere a@lvn/b2
end tlQ3BKp
else 4 )*8&
begin I/_`/mQ
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' -?&wD["y
end UP 75}h9
我们可以直接写成 73rr">
9#0
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere S3`zB?7,
2、收缩数据库 uRh`qnL
--重建索引 0^5SL/2
DBCC REINDEX `\(Fax
DBCC INDEXDEFRAG 7?qRY9Qu
--收缩数据和日志 uf^"Y3
DBCC SHRINKDB 8BhLO.(<O
DBCC SHRINKFILE tB'F`HM:mq
3、压缩数据库 q[] "`?
dbcc shrinkdatabase(dbname) |\*7J!Liv
4、转移数据库给新用户以已存在用户权限 BPIp3i
exec sp_change_users_login 'update_one','newname','oldname' smF#'"{
go |Xlc2?e
5、检查备份集 @w[WG:-+
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' _hMMm6a|
6、修复数据库 qi.|oL9p
ALTER DATABASE [dvbbs] SET SINGLE_USER ; mu9;ixZ
GO cx&jnF#$
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Gyw@+(l
GO `QC{}Oo^
ALTER DATABASE [dvbbs] SET MULTI_USER n1a;vE{!
GO \vs,$h
7、日志清除 L8Z[Ly+_
SET NOCOUNT ON 8tK 8|t5+
DECLARE @LogicalFileName sysname, L/1?PM
@MaxMinutes INT, 89Svx5S
@NewSize INT L L7a20
USE tablename -- 要操作的数据库名 l&dHH_m3
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 E#URTt:&>
@MaxMinutes = 10, -- Limit on time allowed to wrap log. #'mb9GWD3
@NewSize = 1 -- 你想设定的日志文件的大小(M) KxqT5`P&
-- Setup / initialize !O-q13\Y
DECLARE @OriginalSize int Ultx|qU
SELECT @OriginalSize = size z%Op_Ddp
FROM sysfiles <=/v%VXPm
WHERE name = @LogicalFileName Ny/bNQS
SELECT 'Original Size of ' + db_name() + ' LOG is ' + G0^WQQ4
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + u 3wF)B{
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' EtWpB g
FROM sysfiles
4^1{UlCop
WHERE name = @LogicalFileName xO`w|k
CREATE TABLE DummyTrans {
KE[8n
(DummyColumn char (8000) not null) muwXzN(KX
DECLARE @Counter INT, )Mx[;IwE
@StartTime DATETIME, 5][Rvu0
@TruncLog VARCHAR(255) xC9^x7%3O
SELECT @StartTime = GETDATE(), Pwt4e-
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' x#|=.T
DBCC SHRINKFILE (@LogicalFileName, @NewSize) f\!*%xS;
EXEC (@TruncLog) p{"p<XFyO
-- Wrap the log if necessary. CeNpJ
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired
.taJCE
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) #r `hK)
AND (@OriginalSize * 8 /1024) > @NewSize 5H1SC8+B,
BEGIN -- Outer loop. IpXg2QbN
SELECT @Counter = 0 %qcBM~efT
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) OY*BVJ^
BEGIN -- update L,!Z
INSERT DummyTrans VALUES ('Fill Log') a\$PqOB!
DELETE DummyTrans +[V[{n
SELECT @Counter = @Counter + 1 iNZ'qMH22
END @tdX=\[~
EXEC (@TruncLog) g^26Gb.
END $NJ]2P9L
SELECT 'Final Size of ' + db_name() + ' LOG is ' + iOm~
CONVERT(VARCHAR(30),size) + ' 8K pages or ' +
.7ESPr
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 2-ev7:
FROM sysfiles mHE4Es0
WHERE name = @LogicalFileName Z~F% K~(
DROP TABLE DummyTrans T
{a%:=`
SET NOCOUNT OFF 5YUn{qtD
8、说明:更改某个表 #IDDKUE
exec sp_changeobjectowner 'tablename','dbo' .^N+'g
9、存储更改全部表 *,-)4)7d
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch *r!1K!c
@OldOwner as NVARCHAR(128), wh
l)^D
@NewOwner as NVARCHAR(128) W@GcE;#-
AS Sdz!J 1
DECLARE @Name as NVARCHAR(128) j0L9Q|s
DECLARE @Owner as NVARCHAR(128) *YZ'Uy?
DECLARE @OwnerName as NVARCHAR(128) 41>Bm*if
DECLARE curObject CURSOR FOR :Qh5ZO&G0
select 'Name' = name, NDglse
'Owner' = user_name(uid) "ZEJL.Wy
from sysobjects 0I* ^VGZ
where user_name(uid)=@OldOwner Z`v6DfK}
order by name O66\s q
OPEN curObject &ME[H
FETCH NEXT FROM curObject INTO @Name, @Owner %4Ylq|d
WHILE(@@FETCH_STATUS=0) 2/RK
pl &
BEGIN e<dFvMO
if @Owner=@OldOwner G'q7@d{'
begin ]^Z7w`=%5
set @OwnerName = @OldOwner + '.' + rtrim(@Name) \K9XG/XIx
exec sp_changeobjectowner @OwnerName, @NewOwner Nc
F
end RX4O1Z0
-- select @name,@NewOwner,@OldOwner )/PvaL
FETCH NEXT FROM curObject INTO @Name, @Owner ^ ]SS\=7
END D "j
=|4S#
close curObject 8)&yjY
deallocate curObject Z7"8dlb
GO #M&rmKv)g
10、SQL SERVER中直接循环写入数据 @g(N!n~
declare @i int HUr;ysw
set @i=1 64z9Yr@
while @i<30 L.$9ernVY
begin
M.zS +
insert into test (userid) values(@i) ;'!U/N;-
set @i=@i+1 2x{@19w)C
end 17tph;
小记存储过程中经常用到的本周,本月,本年函数 .qi$X!0
Dateadd(wk,datediff(wk,0,getdate()),-1) S,fMGKcq
Dateadd(wk,datediff(wk,0,getdate()),6) Za}*6N=?*
Dateadd(mm,datediff(mm,0,getdate()),0) .+]e9mV
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) *E+2E^B
Dateadd(yy,datediff(yy,0,getdate()),0) aDb@u3X@
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) @xH|(
上面的SQL代码只是一个时间段 9E)*X
Dateadd(wk,datediff(wk,0,getdate()),-1) E^zgYkZO
Dateadd(wk,datediff(wk,0,getdate()),6) E
`Ualai
就是表示本周时间段. 6_=qpP-?
下面的SQL的条件部分,就是查询时间段在本周范围内的: JQYIvo1,Q
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) K~z*P0g*
而在存储过程中 iaQ[}'6!$
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Z^`&