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。 5cL83FQh
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一、基础 (C-{B[Y
1、说明:创建数据库 r3&G)g=u
CREATE DATABASE database-name y&q*maa[
2、说明:删除数据库 Fq~yL!#!
drop database dbname m ZtCL
3、说明:备份sql server #%iDT6
--- 创建 备份数据的 device vj'wm}/
USE master : UGZ+
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Bu<M\w?7Y
--- 开始 备份 ;4R$g5-4X
BACKUP DATABASE pubs TO testBack ;f0I
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4、说明:创建新表 "pi=$/RD9
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) X$
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根据已有的表创建新表: u]<,,
A:create table tab_new like tab_old (使用旧表创建新表) @=bLDTx;c)
B:create table tab_new as select col1,col2... from tab_old definition only \r;#g{
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5、说明:删除新表 L[oui,}_
drop table tabname jaTh^L
6、说明:增加一个列 3oGt3F{gZ
Alter table tabname add column col type 5{|7$VqPF
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 gf#{k2r
7、说明:添加主键: Alter table tabname add primary key(col) -BrMp%C
说明:删除主键: Alter table tabname drop primary key(col) dA@]!
8、说明:创建索引:create [unique] index idxname on tabname(col....) `18qbot
删除索引:drop index idxname [;4g
注:索引是不可更改的,想更改必须删除重新建。 m,*QP*
9、说明:创建视图:create view viewname as select statement nt 81Bk=
删除视图:drop view viewname ?*[N_'2W+
10、说明:几个简单的基本的sql语句 Ygm`ZA y
选择:select * from table1 where 范围 eJF5n#
插入:insert into table1(field1,field2) values(value1,value2) 8p^bD}lN7
删除:delete from table1 where 范围 >:A ARx%
更新:update table1 set field1=value1 where 范围 XX7{-Yy
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! {@H6HqD
排序:select * from table1 order by field1,field2 [desc] .*@;@06?
总数:select count as totalcount from table1 FOv=!'So
求和:select sum(field1) as sumvalue from table1 *W4m3Lq
平均:select avg(field1) as avgvalue from table1 BWeA@v
最大:select max(field1) as maxvalue from table1 [pC$+NX
最小:select min(field1) as minvalue from table1 3c#BKHNC
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11、说明:几个高级查询运算词 zvYq@Mhr
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A: UNION 运算符 aGrIQq/k)%
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。 9=vMgW
B: EXCEPT 运算符 p#ol*m5wE
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。 A_XY'z 1
C: INTERSECT 运算符 mC4zactv
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。 N|8P)
注:使用运算词的几个查询结果行必须是一致的。 <":;+Ng+
12、说明:使用外连接 dbwe?ksh
A、left outer join: :8L8q<U
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。 Ff$L|
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 AsQ)q
B:right outer join: ~+Rc}K
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。 i2@VB6]?
C:full outer join: fV &KM*W*@
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。 *"+=K,#D
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二、提升 l Q'I
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Nh8Q b/::
法一:select * into b from a where 1<>1 NTdixfR
法二:select top 0 * into b from a ]mo-rhDsM
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) eK6hS_E
insert into b(a, b, c) select d,e,f from b; |8&,b`Gfo
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) :Ux?,
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Qiua
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. V@B__`y7
4、说明:子查询(表名1:a 表名2:b) 3VsW@SG7N
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) WzPTFw[
5、说明:显示文章、提交人和最后回复时间 q
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select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 2QD3&Q9
6、说明:外连接查询(表名1:a 表名2:b) 9i'jjN
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c *S]Ci\{_
7、说明:在线视图查询(表名1:a ) Q}1 R5@7
select * from (SELECT a,b,c FROM a) T where t.a > 1; LIS)(X<]?
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 9 %8"e>~
select * from table1 where time between time1 and time2 *EOdEFsR/
select a,b,c, from table1 where a not between 数值1 and 数值2 na#CpS;pc
9、说明:in 的使用方法 qIVx9jNN
select * from table1 where a [not] in ('值1','值2','值4','值6') 8qY79)vD4E
10、说明:两张关联表,删除主表中已经在副表中没有的信息 %b%-Ogz;4
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ))R5(R
11、说明:四表联查问题: q+Lr"&'Q
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 ..... t|H^`Cv6
12、说明:日程安排提前五分钟提醒 cQ/5qg
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 f1`gdQ)H
13、说明:一条sql 语句搞定数据库分页 !Z`j2
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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 aUzBV\Yd}
14、说明:前10条记录 :V1W/c
select top 10 * form table1 where 范围 MC?,UDNd%
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.) gcE|#1>
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) #D<C )Q
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 bP8Sj16q
(select a from tableA ) except (select a from tableB) except (select a from tableC) O;z,qo X
17、说明:随机取出10条数据 o}$XH,-9&
select top 10 * from tablename order by newid() {\S+#W\
18、说明:随机选择记录 qmnZAk
select newid() !2 LCLN\
19、说明:删除重复记录 NMW#AZVd
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) jq-p;-i
20、说明:列出数据库里所有的表名 DQNnNsP:M-
select name from sysobjects where type='U' 3
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21、说明:列出表里的所有的 &%8'8,.
select name from syscolumns where id=object_id('TableName') Ky|88~}:C9
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。 8I-u2Y$Sr
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type `NnUyQ;T
显示结果: Usr@uI#{J
type vender pcs TkE 8D
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电脑 A 1 Gn\_+Pj$
电脑 A 1 /mXBvY
光盘 B 2 [OjF[1I)u
光盘 A 2 ?5U2D%t
手机 B 3 +EFgE1w
手机 C 3 -u&6X,Oq\u
23、说明:初始化表table1 9:fOYT$8
TRUNCATE TABLE table1 ?Eg(Gu.J
24、说明:选择从10到15的记录 Q~814P8]
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc x4g3rmp
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三、技巧 3 j!3E
1、1=1,1=2的使用,在SQL语句组合时用的较多 }XZ'v_Ti
"where 1=1" 是表示选择全部 "where 1=2"全部不选, iDN;m`a
如: X'wE7=29M
if @strWhere !='' |>27'#JC
begin J cg,#@
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere _,zA ^*b
end g3Ec"_>P
else Mx6@$tQ%
begin M^MdRu
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' {n(b{ibl
end ;6gDV`Twy
我们可以直接写成 5j:0Yt
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 4,..kSA3iw
2、收缩数据库 h"Xg;(K
--重建索引 g+DzscIT
DBCC REINDEX 9!f/aI
DBCC INDEXDEFRAG uG?_< mun
--收缩数据和日志 QBtnx[
DBCC SHRINKDB l=]cy-H
DBCC SHRINKFILE FjK3
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3、压缩数据库 0T@ Zb={
dbcc shrinkdatabase(dbname) D5$wTI
4、转移数据库给新用户以已存在用户权限 Q<z_/j9
exec sp_change_users_login 'update_one','newname','oldname' 5 elw~u
go E_Im^a
5、检查备份集 6^%UU
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' LL] zT H0
6、修复数据库 @WJgWJm
ALTER DATABASE [dvbbs] SET SINGLE_USER /nyUG^5#{
GO /4t j3B,
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK
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GO (H)2s Y
ALTER DATABASE [dvbbs] SET MULTI_USER 4 d;|sI@
GO |w_7_J2
7、日志清除 WEFlV4/
SET NOCOUNT ON t]>Lh>G
DECLARE @LogicalFileName sysname, &Q+Ln,(&L
@MaxMinutes INT, e@c0WlWa
@NewSize INT \x)n>{3C
USE tablename -- 要操作的数据库名 c#a@n 4
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 anIAM
@MaxMinutes = 10, -- Limit on time allowed to wrap log. E8>Rui@9
@NewSize = 1 -- 你想设定的日志文件的大小(M) >G);j@Q
-- Setup / initialize g1XZ5P} f
DECLARE @OriginalSize int S7=Bd[4
SELECT @OriginalSize = size q+P|l5_
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FROM sysfiles Nqw&< x+
WHERE name = @LogicalFileName >fe-d#!{
SELECT 'Original Size of ' + db_name() + ' LOG is ' + umD!2
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Fp@TCPe#
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 6^uq?
FROM sysfiles {8 8 )~
WHERE name = @LogicalFileName eyefW n&
CREATE TABLE DummyTrans kdCUORMK
(DummyColumn char (8000) not null) fYp'&Btb]x
DECLARE @Counter INT, @[5xq
@StartTime DATETIME, J%x6
@TruncLog VARCHAR(255) W)9K`hM6
SELECT @StartTime = GETDATE(), MG[o%I96
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' N e#WI'
DBCC SHRINKFILE (@LogicalFileName, @NewSize) +lJG(Qd
EXEC (@TruncLog) ${+ @gJ+S
-- Wrap the log if necessary. cU0s
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired *4_jA](
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ^
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AND (@OriginalSize * 8 /1024) > @NewSize a-l;vDs
BEGIN -- Outer loop. *&?c(JU;<
SELECT @Counter = 0 HU%o6c w
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) K/A*<<r
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BEGIN -- update 8d?g]DEN)6
INSERT DummyTrans VALUES ('Fill Log') q2. XoCf
DELETE DummyTrans ?z}=B
SELECT @Counter = @Counter + 1 u @~JiiC%
END n9@ of
EXEC (@TruncLog) f~Fm4>\(
END ,z3{u162
SELECT 'Final Size of ' + db_name() + ' LOG is ' + b|cyjDMAA
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ~2<7ZtV=
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' CF+_/s#j^
FROM sysfiles 350_CN,
WHERE name = @LogicalFileName u`y><w4i
DROP TABLE DummyTrans J\d3N7_d
SET NOCOUNT OFF MxSM@3 v(
8、说明:更改某个表 )ap_Z6
exec sp_changeobjectowner 'tablename','dbo' +
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9、存储更改全部表 #?q&r_@@
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch j;s"q]"x]
@OldOwner as NVARCHAR(128), !6s"]WvF
@NewOwner as NVARCHAR(128) V+Cwzc^j
AS /DQc&.jK
DECLARE @Name as NVARCHAR(128) M%1}/!J3
DECLARE @Owner as NVARCHAR(128) Q>/C*@
DECLARE @OwnerName as NVARCHAR(128) j{Hao\F8
DECLARE curObject CURSOR FOR Jj,U RD&0R
select 'Name' = name, {z(xFrY
'Owner' = user_name(uid) T32+3wb"I
from sysobjects W5?yy>S6N
where user_name(uid)=@OldOwner
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order by name GytXFL3`:
OPEN curObject N` aF{3[
FETCH NEXT FROM curObject INTO @Name, @Owner HHq_P/'
WHILE(@@FETCH_STATUS=0) M@4UGM`J
BEGIN .mDM[e@'
if @Owner=@OldOwner SG-'R1
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begin w4W_iaU
set @OwnerName = @OldOwner + '.' + rtrim(@Name) B*4}GPQ
exec sp_changeobjectowner @OwnerName, @NewOwner Nc+,&R13m
end wNQ*t-K
-- select @name,@NewOwner,@OldOwner uHAT#\m:
FETCH NEXT FROM curObject INTO @Name, @Owner Jd5:{{Lb
END (>`5z(X
close curObject 356>QW'm
deallocate curObject ]l'Y'z,}
GO cgl*t+o&
10、SQL SERVER中直接循环写入数据 9AxCiT.
declare @i int U+)xu>I
set @i=1 ZKQG:M~|
while @i<30 ogL EtqT
begin jV?
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insert into test (userid) values(@i) PQK(0iCo4
set @i=@i+1 k]5Bykf`Ky
end SVv;q?jZ
小记存储过程中经常用到的本周,本月,本年函数 TJ:]SB
Dateadd(wk,datediff(wk,0,getdate()),-1) h~(G$':^
Dateadd(wk,datediff(wk,0,getdate()),6) krsYog(^z
Dateadd(mm,datediff(mm,0,getdate()),0) M7ers|&{
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ;QW3CEaUq
Dateadd(yy,datediff(yy,0,getdate()),0) AtF3%Zv2
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) pGf@z:^{*-
上面的SQL代码只是一个时间段 {e+-vl
Dateadd(wk,datediff(wk,0,getdate()),-1) ?[)}l9
Dateadd(wk,datediff(wk,0,getdate()),6) io#&o;M<
就是表示本周时间段. UB 6mqjPK
下面的SQL的条件部分,就是查询时间段在本周范围内的:
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) (FJ9-K0b{n
而在存储过程中 L=q+|j1>
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) p98~&\QT
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ?t+5s]