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。 moZm0`WR
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一、基础 s$ z2 c
1、说明:创建数据库 N 9LgU)-Jt
CREATE DATABASE database-name u okc:D
2、说明:删除数据库 4x=(Zw_X
drop database dbname -{{[cTI
3、说明:备份sql server X#`dWNrN
--- 创建 备份数据的 device C?o6(p"b
USE master G\kpUdj}
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 4MLH+/e
--- 开始 备份 TH:W#Ot
BACKUP DATABASE pubs TO testBack 59lj7
4、说明:创建新表 sJU`u'w
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) vy9dAl
根据已有的表创建新表: ]iVLHVqz
A:create table tab_new like tab_old (使用旧表创建新表) Ur3m[07H
B:create table tab_new as select col1,col2... from tab_old definition only WbcS: !0
5、说明:删除新表 n_23EcSy
drop table tabname 8:dQ._#v
6、说明:增加一个列 5FOqv=6S
Alter table tabname add column col type q7_+}"i
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。 0BK5qz
7、说明:添加主键: Alter table tabname add primary key(col) ?\y%]1
说明:删除主键: Alter table tabname drop primary key(col) |<c
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8、说明:创建索引:create [unique] index idxname on tabname(col....) 5jZiJw(
删除索引:drop index idxname E ]f)Os$
注:索引是不可更改的,想更改必须删除重新建。 D(\$i.,b2
9、说明:创建视图:create view viewname as select statement [>Fm[5x
删除视图:drop view viewname _ck[&Q
10、说明:几个简单的基本的sql语句 #|f~s
选择:select * from table1 where 范围 JN(-.8<
插入:insert into table1(field1,field2) values(value1,value2) *x(Jq?5O7X
删除:delete from table1 where 范围 >2lwWXA
更新:update table1 set field1=value1 where 范围 pj8azFZ
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! e;(
排序:select * from table1 order by field1,field2 [desc] VaR/o#
总数:select count as totalcount from table1 U>Gg0`>
求和:select sum(field1) as sumvalue from table1 b1-&v|L
平均:select avg(field1) as avgvalue from table1 Bp_wnd
最大:select max(field1) as maxvalue from table1 (MLhaux-
最小:select min(field1) as minvalue from table1 +@:L|uFU
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11、说明:几个高级查询运算词 y{=>$C[
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A: UNION 运算符 t'(1I|7
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 goZ V.,w
B: EXCEPT 运算符 <Ef[c@3
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 e.vtEQV9
C: INTERSECT 运算符 5o0Ch
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 kbI/4IRW
注:使用运算词的几个查询结果行必须是一致的。 NX,-;v
12、说明:使用外连接 qLK?%?.N<
A、left outer join: Jp~zX
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左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 X.V[0$.;
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 L:R<e#kgS
B:right outer join: \#Up|u:
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。 DL8x":;
C:full outer join: 8Vn4.R[vE
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。 7o]HQ[ xO
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二、提升 ^}$O|t
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 5?u}#zO
法一:select * into b from a where 1<>1 ^jSsa
法二:select top 0 * into b from a ,wj"! o#
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) "![L#)"s
insert into b(a, b, c) select d,e,f from b; qoX@@xr1
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) ~Xv=9@,h
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ELD!{bMT
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. JAjku6
4、说明:子查询(表名1:a 表名2:b) \ |!\V
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) K$[$4 dX]
5、说明:显示文章、提交人和最后回复时间 57I}RMT"
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b #&8rcu;/
6、说明:外连接查询(表名1:a 表名2:b) AkBMwV
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c \RG!@$i
7、说明:在线视图查询(表名1:a ) Lx[
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select * from (SELECT a,b,c FROM a) T where t.a > 1; Wf26
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 cgT
select * from table1 where time between time1 and time2 !0}\&<8/m
select a,b,c, from table1 where a not between 数值1 and 数值2 TzG]WsY_
9、说明:in 的使用方法 e%O0hE
select * from table1 where a [not] in ('值1','值2','值4','值6') ftbpqp'
10、说明:两张关联表,删除主表中已经在副表中没有的信息 01@t~v3!Z
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) md Gwh7/3
11、说明:四表联查问题: 04@cLDX8uB
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 ..... RHY4P4B<v>
12、说明:日程安排提前五分钟提醒 #JW+~FU`
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 9pSUIl9|j
13、说明:一条sql 语句搞定数据库分页 Ud(`V:d
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 *_-'/i
14、说明:前10条记录 kxB.,'
select top 10 * form table1 where 范围 Y%aWK~O
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.) rZ03x\2
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) -ysn&d\rV
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 7jG(<!,
(select a from tableA ) except (select a from tableB) except (select a from tableC) ROb\Rxm
17、说明:随机取出10条数据 dK9Zg,DZL
select top 10 * from tablename order by newid() kLP0{A
18、说明:随机选择记录 LHYLC>J
select newid() X$n(-65
19、说明:删除重复记录 zu\`1W^
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 7/IlL
20、说明:列出数据库里所有的表名 3iNkoBCg
select name from sysobjects where type='U' @%ECj)u`O
21、说明:列出表里的所有的 f'Mop= .
select name from syscolumns where id=object_id('TableName') zGo|JF
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 K\?]$dK5
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 DBH#)4do@
显示结果: k;^
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type vender pcs uE5X~
电脑 A 1 P:xT0gtt
电脑 A 1 hpbf&S4
光盘 B 2 8Cx^0
光盘 A 2 1Y j~fb(
手机 B 3 YK#fa2ng
手机 C 3 Dl\`
23、说明:初始化表table1 x!<yT?A
TRUNCATE TABLE table1 |V,<+BEi
24、说明:选择从10到15的记录 \IM4Z|NN"
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc mEAXM1J|
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三、技巧 2f:^S/.A
1、1=1,1=2的使用,在SQL语句组合时用的较多 evuZY X@
"where 1=1" 是表示选择全部 "where 1=2"全部不选, BOVPKX
如: Q[4:
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if @strWhere !='' fxQN+6;
begin $iw%(H
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ^"8wUsP
end Hf gz02Z$
else b7:0#l$
begin s][24)99
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' [U{UW4
end %eWqQ3{P]
我们可以直接写成 }Fb!?['G5
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 4"?^UBr
2、收缩数据库 SX0_v_%M
--重建索引 N@T.T=r
DBCC REINDEX ed!>)Cb
DBCC INDEXDEFRAG V
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--收缩数据和日志 pW\'ZRj
DBCC SHRINKDB )X+mV
DBCC SHRINKFILE [5d2D,)
3、压缩数据库 qCQ./"8
dbcc shrinkdatabase(dbname) 15\Ph[6g
4、转移数据库给新用户以已存在用户权限 uZjC
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exec sp_change_users_login 'update_one','newname','oldname' c,\i"=!$
go z_|oCT!6
5、检查备份集 5z$,6T
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' i'/m4 !>h
6、修复数据库 2h=%K/hhY
ALTER DATABASE [dvbbs] SET SINGLE_USER HfNDD|Zz
GO ^ZRYRA
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK X@2-*so<
GO J;Rv ~<7
ALTER DATABASE [dvbbs] SET MULTI_USER Zo-$z8
GO },$0&/>ft
7、日志清除 g{k1&|
SET NOCOUNT ON ]3{0J
DECLARE @LogicalFileName sysname, :3h{ A`u
@MaxMinutes INT, %|W.^q
@NewSize INT l ,|%7-
USE tablename -- 要操作的数据库名 a6xj\w
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 7*+]wEs
@MaxMinutes = 10, -- Limit on time allowed to wrap log. RzKb{>
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@NewSize = 1 -- 你想设定的日志文件的大小(M) NPnHH:\;
-- Setup / initialize %:v`EjRD0
DECLARE @OriginalSize int =qVP] 9
SELECT @OriginalSize = size ~#K@ADYr
FROM sysfiles gk0.zz([
WHERE name = @LogicalFileName 6aft$A}XnD
SELECT 'Original Size of ' + db_name() + ' LOG is ' + _o3e]{
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + nSx8E7 |V
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' (t^n'V
FROM sysfiles ~:4kU/]
WHERE name = @LogicalFileName -NGK@Yk22
CREATE TABLE DummyTrans N3BL3:@O
(DummyColumn char (8000) not null) 8,T4lb<<
DECLARE @Counter INT, IIFMYl gF
@StartTime DATETIME, v5}X+'
@TruncLog VARCHAR(255) {lG@hN'
SELECT @StartTime = GETDATE(), E$s/]wnr[
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' kh$_!BT
DBCC SHRINKFILE (@LogicalFileName, @NewSize) #Il_J\#
EXEC (@TruncLog) PG%0yv%
-- Wrap the log if necessary. R{YzH56M
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired a
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) +FG$x/\*0
AND (@OriginalSize * 8 /1024) > @NewSize C]u',9,
BEGIN -- Outer loop. 9' 1B/{
SELECT @Counter = 0 E\7m<'R
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) %V!iQzL1
BEGIN -- update LwqC~N
INSERT DummyTrans VALUES ('Fill Log') -;(Q1)&
DELETE DummyTrans =HDI \LD<
SELECT @Counter = @Counter + 1 q Dd~2"er
END }Nj97R
EXEC (@TruncLog) j1$8#/r;c
END RF}X
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + j-@kW'K
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + +>^7vq-\'
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' <Q< AwP
FROM sysfiles <z+:j!~
WHERE name = @LogicalFileName
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DROP TABLE DummyTrans Y&bMCI6U
SET NOCOUNT OFF Z$KLl((
8、说明:更改某个表 D|bBu
exec sp_changeobjectowner 'tablename','dbo' R"Liz3Vl%
9、存储更改全部表 's?Ai2=#
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Nt`b;X&
@OldOwner as NVARCHAR(128), S:Q! "U
@NewOwner as NVARCHAR(128) ~^I>#Dd
AS >>Ar$
DECLARE @Name as NVARCHAR(128)
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DECLARE @Owner as NVARCHAR(128) }l0&a!C
DECLARE @OwnerName as NVARCHAR(128) >cMd\%^t
DECLARE curObject CURSOR FOR P\m7 -
select 'Name' = name, LHCsk{3
'Owner' = user_name(uid) _;9!
from sysobjects ihe(F7\U
where user_name(uid)=@OldOwner 9v)%dO.
order by name R,2=&+ e
OPEN curObject D>L2o88
FETCH NEXT FROM curObject INTO @Name, @Owner K<sC F[
WHILE(@@FETCH_STATUS=0) WKM)*@#,
BEGIN !eR3@%4
if @Owner=@OldOwner rZ1Hf11C
begin $P
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) $o?@0
exec sp_changeobjectowner @OwnerName, @NewOwner eJ8]g49mD6
end 2C^B_FUg|]
-- select @name,@NewOwner,@OldOwner p0p4Xh1e
FETCH NEXT FROM curObject INTO @Name, @Owner 'XOX@UH d
END e;YW6}'}
close curObject mABe'"8
deallocate curObject b;mSQ4+
GO \uOdALZ
10、SQL SERVER中直接循环写入数据 h[tix:
declare @i int `s#Hq\C
set @i=1 m`?MV\^
while @i<30 A1Y7;-D
begin 2(!fg4#+
insert into test (userid) values(@i) KU9Z"9#
set @i=@i+1 #Doq P:
end SjEAuRDvUz
小记存储过程中经常用到的本周,本月,本年函数 |+IZS/W"
Dateadd(wk,datediff(wk,0,getdate()),-1) ,1{Ep`
Dateadd(wk,datediff(wk,0,getdate()),6) hqSJ(gs{
Dateadd(mm,datediff(mm,0,getdate()),0) :6kj EI
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) h~Q)Uy5N(D
Dateadd(yy,datediff(yy,0,getdate()),0) X<OSN&d
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) #.B"q:CW*P
上面的SQL代码只是一个时间段 =nUW'
Dateadd(wk,datediff(wk,0,getdate()),-1) *!e(A ]&
Dateadd(wk,datediff(wk,0,getdate()),6) Rhzn/\)|
就是表示本周时间段. T5Eseesp
下面的SQL的条件部分,就是查询时间段在本周范围内的: u'A#%}3
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ~3h-j K?
而在存储过程中 pY8q=Kl
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) JWP*>\P
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) V:NI4dv/R