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。 @qfVt
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一、基础 ~ZSP K;D[
1、说明:创建数据库 T`;>Kq:s
CREATE DATABASE database-name JWa9[Dj
2、说明:删除数据库 x"Hi!h)v
drop database dbname <Cvlz^K[
3、说明:备份sql server H-9%/e
--- 创建 备份数据的 device I]]3=?Y
USE master tBp146`
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' GB(o)I#h
--- 开始 备份 Ua^'KRSO
BACKUP DATABASE pubs TO testBack "(hhb>V1Wl
4、说明:创建新表 R^.oM1qu|
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) =-`}(b2N
根据已有的表创建新表: d (Fb_
A:create table tab_new like tab_old (使用旧表创建新表) 7J]tc1-re
B:create table tab_new as select col1,col2... from tab_old definition only E0<9NFQr7
5、说明:删除新表 aMSX"N"ot
drop table tabname -|MeC
6、说明:增加一个列 -$E_L:M
Alter table tabname add column col type 8}\Lt
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。 /.<T^p@\&
7、说明:添加主键: Alter table tabname add primary key(col) vMiZ:*iaj@
说明:删除主键: Alter table tabname drop primary key(col) HXTBxh
8、说明:创建索引:create [unique] index idxname on tabname(col....) [lqwzW{(UN
删除索引:drop index idxname '*5I5'[ X,
注:索引是不可更改的,想更改必须删除重新建。 LFCcV<~
9、说明:创建视图:create view viewname as select statement 3%]%c6
删除视图:drop view viewname $/aZ/O)F
10、说明:几个简单的基本的sql语句 xq2{0q
选择:select * from table1 where 范围 ^G+1nY4?J
插入:insert into table1(field1,field2) values(value1,value2) x?:[:Hf
删除:delete from table1 where 范围 F#X&Tb{
更新:update table1 set field1=value1 where 范围 -bo5/`x
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 2Y)3Ue
排序:select * from table1 order by field1,field2 [desc] jmbwV,@Q2
总数:select count as totalcount from table1 +s:!\(BM
求和:select sum(field1) as sumvalue from table1 }@Ij}Ab>
平均:select avg(field1) as avgvalue from table1 `/:ZB6
最大:select max(field1) as maxvalue from table1 _-&\~w
最小:select min(field1) as minvalue from table1 ~Cx07I_lf
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11、说明:几个高级查询运算词 + RX{
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A: UNION 运算符 !>g_9'n'
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。 oZxC.;xJ
B: EXCEPT 运算符 Ll%CeP
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。 5Xu2MY=
C: INTERSECT 运算符 %nQii?1`i
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。 c(.2D
注:使用运算词的几个查询结果行必须是一致的。 Kv'2^B
12、说明:使用外连接 CA)DQYp{
A、left outer join: "P<IQx
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。 NDW6UFd>1
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 wfQ6J0
B:right outer join: 6fhH)]0
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。 0Zp)
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C:full outer join: Amf
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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。 tr6<89e(o
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二、提升 P08=?
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) +1R?R9^Fw
法一:select * into b from a where 1<>1 a9C8Q
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法二:select top 0 * into b from a Ah,X?0+
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) n}MW# :eJe
insert into b(a, b, c) select d,e,f from b; *Ppb;
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) D<5;4Mb
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 FUic7>
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. oa(R,{_*q
4、说明:子查询(表名1:a 表名2:b) nqNL[w6{
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) fr$E'+l)
5、说明:显示文章、提交人和最后回复时间 }{Ab:+aNd
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b o(GXv3L
6、说明:外连接查询(表名1:a 表名2:b) K,{P
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 'M>QA"*48E
7、说明:在线视图查询(表名1:a ) YIv!\`^ \
select * from (SELECT a,b,c FROM a) T where t.a > 1; 3-z;pk
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 ]zEatY
select * from table1 where time between time1 and time2 <R)%K);
select a,b,c, from table1 where a not between 数值1 and 数值2 p
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9、说明:in 的使用方法 ?.d6!vA
select * from table1 where a [not] in ('值1','值2','值4','值6') \ s^a4l2
10、说明:两张关联表,删除主表中已经在副表中没有的信息 xT7JGQ[|
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) P` Hxj> {
11、说明:四表联查问题: InnjZ>$
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 ..... Gf'qPLK0
12、说明:日程安排提前五分钟提醒 G+2!+N\P
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 u`I&&
13、说明:一条sql 语句搞定数据库分页 :ulOG{z
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 H`#{zt);
14、说明:前10条记录 A)9OkLrc
select top 10 * form table1 where 范围 o!W
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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.) ol QT r
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) #@s[!4)_I
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 \ vj<9ke&
(select a from tableA ) except (select a from tableB) except (select a from tableC) ?.tnaE
17、说明:随机取出10条数据 F!DDlYUz.
select top 10 * from tablename order by newid() LT7C>b
18、说明:随机选择记录 (}ObX!,
select newid() Y5nj _xQJL
19、说明:删除重复记录 Y 3W_Z
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) w U".^
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20、说明:列出数据库里所有的表名 8aDhHXI
select name from sysobjects where type='U' s8L=:hiSf)
21、说明:列出表里的所有的 32nB9[l
select name from syscolumns where id=object_id('TableName') <d89eV+
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。 ~9%L)nC2'
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 _m .u@+g
显示结果: DX>Yf}
type vender pcs VfWU-lJ
电脑 A 1 /J''`Tf
电脑 A 1 LpCJfQ
光盘 B 2 KE>|,Ur
光盘 A 2 v_M-:e3`
手机 B 3 WzD=Ol
手机 C 3 1iNq|~
23、说明:初始化表table1 Qh*"B
TRUNCATE TABLE table1 En01LrC?
24、说明:选择从10到15的记录 {m%]`0
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc f793yCiG
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三、技巧 .[mI9dc
1、1=1,1=2的使用,在SQL语句组合时用的较多 Hw"LoVh
"where 1=1" 是表示选择全部 "where 1=2"全部不选, r<< ]41
如: M_
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if @strWhere !='' S7i,oP7
begin 8EbJ5wu/%S
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere &CP]+ at
end Qy0Zj$,Z
else ^j~CYzmt
begin >3aB{[[N
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' imb.CYS74
end B^|^hZZ>
我们可以直接写成 vndD#/lXq
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere K
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2、收缩数据库 ckDWY<@v
--重建索引 t`F<lOKj
DBCC REINDEX >|j8j:S[
DBCC INDEXDEFRAG i|N%dl+T=
--收缩数据和日志 SZ$~zT;c
DBCC SHRINKDB K=Q<G:+&V
DBCC SHRINKFILE w3hG\2)[HS
3、压缩数据库 dgbqMu"
dbcc shrinkdatabase(dbname) m2sf]-?Y
4、转移数据库给新用户以已存在用户权限 ^@91BY
exec sp_change_users_login 'update_one','newname','oldname' Hs9; &C
go $TU:iv1Fm
5、检查备份集 Dx1f<A1
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' =74yhPAW
6、修复数据库 YCBp]xuE
ALTER DATABASE [dvbbs] SET SINGLE_USER {3)^$F=T
GO LIah'6qR
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ;@5N
GO XC*!=h*
ALTER DATABASE [dvbbs] SET MULTI_USER _8QHx;}
GO <GdQ""X
7、日志清除 4hl`~&yDf
SET NOCOUNT ON 62s0$vw
DECLARE @LogicalFileName sysname, ~)fd+~4L
@MaxMinutes INT, |.]g&m)y^h
@NewSize INT &];:uYmMU
USE tablename -- 要操作的数据库名 \d:AV(u
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 5xb1FH d:
@MaxMinutes = 10, -- Limit on time allowed to wrap log. PxAUsY
@NewSize = 1 -- 你想设定的日志文件的大小(M) 6gy;Xg
-- Setup / initialize ta;q{3fe
DECLARE @OriginalSize int s?j ||
SELECT @OriginalSize = size N6R0$Br
FROM sysfiles bM@8[&ta
WHERE name = @LogicalFileName Ca]V%g(
SELECT 'Original Size of ' + db_name() + ' LOG is ' + wC&+nS1
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + v%
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' vV$6fvS
FROM sysfiles aG*Mj;J
WHERE name = @LogicalFileName +uqP:z
CREATE TABLE DummyTrans (Zi,~Wqm$
(DummyColumn char (8000) not null) pw,
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DECLARE @Counter INT, s[dq-pc"
@StartTime DATETIME, +.3,(l
@TruncLog VARCHAR(255) cXDG(.!n7B
SELECT @StartTime = GETDATE(), K?J?]VCw
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' =w,cdU*
DBCC SHRINKFILE (@LogicalFileName, @NewSize) KtMD?
EXEC (@TruncLog) V#Pz`D
-- Wrap the log if necessary. d,V] j-
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired RCC~#bb
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) gH
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AND (@OriginalSize * 8 /1024) > @NewSize Au"7w=G`f
BEGIN -- Outer loop. m[w 8|[
SELECT @Counter = 0 GZx?vSoHh
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) (@(rz/H
BEGIN -- update LX%UkfA9
INSERT DummyTrans VALUES ('Fill Log') 6'a1]K
DELETE DummyTrans (?ofL|Cg(
SELECT @Counter = @Counter + 1 e$Npo<u
END O!3`^_.
EXEC (@TruncLog) >|W\8dTQ
END dN)@/R^E;
SELECT 'Final Size of ' + db_name() + ' LOG is ' + :c/](M
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + o0B3G
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB'
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FROM sysfiles BpR#3CfW
WHERE name = @LogicalFileName )4O* D92
DROP TABLE DummyTrans }"\jB
SET NOCOUNT OFF &Jf67\N
8、说明:更改某个表 a?
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exec sp_changeobjectowner 'tablename','dbo' eb*w$|y6"
9、存储更改全部表 yv+DM`0
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch o|njgmF;\
@OldOwner as NVARCHAR(128), |+h8g@;Z
@NewOwner as NVARCHAR(128) x7!YA>
AS m&I5~kD
DECLARE @Name as NVARCHAR(128) wK*b2r}0/
DECLARE @Owner as NVARCHAR(128) 0(h'ZV
DECLARE @OwnerName as NVARCHAR(128) ,\CG}-v@CN
DECLARE curObject CURSOR FOR (
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select 'Name' = name, }'c@E0"
'Owner' = user_name(uid) z@tIC^s
from sysobjects g@s'-8}X^
where user_name(uid)=@OldOwner ,/1[(^e
order by name -Izc-W
OPEN curObject !fT3mI6u\
FETCH NEXT FROM curObject INTO @Name, @Owner TM*<hC
WHILE(@@FETCH_STATUS=0) k1sR^&{l
BEGIN j"J[dlm2M
if @Owner=@OldOwner ]/TqPOi:
begin
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) |$QL>{81
exec sp_changeobjectowner @OwnerName, @NewOwner Fq`wx
end rvwfQ'14
-- select @name,@NewOwner,@OldOwner Z#_ +yw
FETCH NEXT FROM curObject INTO @Name, @Owner hcJny
END cuUlr
close curObject noSBwP|v*
deallocate curObject bqI| wGCA"
GO ?]Z EK8c
10、SQL SERVER中直接循环写入数据 ?cmv;KV
declare @i int F qH@iZ
set @i=1 zrazFI0G
while @i<30 'boAv%1_sa
begin nv-_\M
insert into test (userid) values(@i) +jrMvk"
set @i=@i+1 c
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end YA'_Ba(v)
小记存储过程中经常用到的本周,本月,本年函数 jb
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Dateadd(wk,datediff(wk,0,getdate()),-1) mj^]e/s%
Dateadd(wk,datediff(wk,0,getdate()),6) n<3*7/-
Dateadd(mm,datediff(mm,0,getdate()),0) h_?#.z0ih;
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 1z5\>F
Dateadd(yy,datediff(yy,0,getdate()),0) N^U<;O?YDW
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) $P7G,0-
上面的SQL代码只是一个时间段 I]B[H6
Dateadd(wk,datediff(wk,0,getdate()),-1) 0ofl,mXW
Dateadd(wk,datediff(wk,0,getdate()),6) cd?a rIV5
就是表示本周时间段. Z`97=:W
下面的SQL的条件部分,就是查询时间段在本周范围内的: |@lVFEl]
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) :eR[lR^4*
而在存储过程中 Mz:t[rfs
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) r\f|r$i
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) WC
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