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。 ]cvP !
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一、基础
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1、说明:创建数据库
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CREATE DATABASE database-name ?5(Cwy ?
2、说明:删除数据库 T$[50~
drop database dbname w.w(*5[
3、说明:备份sql server t]LOBy-Kv
--- 创建 备份数据的 device !5lb+%7
USE master "J|{'k`
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' xi|T7,\X
--- 开始 备份 c:(Xkzj
BACKUP DATABASE pubs TO testBack %O]]La
4、说明:创建新表 53efF bo
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) #!="b8F
根据已有的表创建新表: -\C;2&(
A:create table tab_new like tab_old (使用旧表创建新表) r:fMd3;gq
B:create table tab_new as select col1,col2... from tab_old definition only BEWDTOY[
5、说明:删除新表 gXZl3
drop table tabname hKo& ZWPq
6、说明:增加一个列 yf3c-p
Alter table tabname add column col type <4r3ZV;'
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。 ?`ETlFtD4
7、说明:添加主键: Alter table tabname add primary key(col) .|Unq`ll
说明:删除主键: Alter table tabname drop primary key(col) 6v(?Lr`D
8、说明:创建索引:create [unique] index idxname on tabname(col....) OolYQU1_
删除索引:drop index idxname L-Io!msb
注:索引是不可更改的,想更改必须删除重新建。 C sXV0
9、说明:创建视图:create view viewname as select statement }ZaZPB/_}P
删除视图:drop view viewname /BEE.`6yI5
10、说明:几个简单的基本的sql语句 QP HibPP:
选择:select * from table1 where 范围 1.29%O8V_
插入:insert into table1(field1,field2) values(value1,value2) L-.
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删除:delete from table1 where 范围 u7 s-
更新:update table1 set field1=value1 where 范围 />^ sGB
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Msj(>U&}+
排序:select * from table1 order by field1,field2 [desc] Sep/N"7~t
总数:select count as totalcount from table1 %l{0z<
求和:select sum(field1) as sumvalue from table1 =^a Ngq
平均:select avg(field1) as avgvalue from table1 (lPiv+'n
最大:select max(field1) as maxvalue from table1 IZ?+c@t
最小:select min(field1) as minvalue from table1 j{ QzD^t
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11、说明:几个高级查询运算词 ux>wa+XFa
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A: UNION 运算符 p1}umDb%
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。 rjk{9u1a"
B: EXCEPT 运算符 G,o5JL"t
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。 JK.<(=y\
C: INTERSECT 运算符 $W} YXLFj?
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 4WspPHj
注:使用运算词的几个查询结果行必须是一致的。 1nGpW$Gx
12、说明:使用外连接 Q`= ,&;T>
A、left outer join: n:dnBwY
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。 f%#q}vK-
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 'P'f`;'_DC
B:right outer join: lqaOLZH
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。 ,u.G6"<
C:full outer join: vG X
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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。 {N.JA=
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二、提升 NgI n\)
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Xg<R+o
法一:select * into b from a where 1<>1 7bk=D~/nSg
法二:select top 0 * into b from a .|?UqZ(,
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) W"3YA+qpI
insert into b(a, b, c) select d,e,f from b; <D}yqq@|
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) |FED<
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 'tJb(X!]q
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. =[_=y=G
4、说明:子查询(表名1:a 表名2:b) qS|ns'[
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) 5`>%{ o
5、说明:显示文章、提交人和最后回复时间 "+dByaY
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b yxx9h3
6、说明:外连接查询(表名1:a 表名2:b) >^!)G^B
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 6j2mr6o
7、说明:在线视图查询(表名1:a ) J?y0RX
select * from (SELECT a,b,c FROM a) T where t.a > 1; Xzn}gH]
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 bz'#YM
select * from table1 where time between time1 and time2 *@+E82D
select a,b,c, from table1 where a not between 数值1 and 数值2 Z@1vJH6IbA
9、说明:in 的使用方法 lEXER^6
select * from table1 where a [not] in ('值1','值2','值4','值6') Mp-hNO}.Z
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Q0j4c
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Y'&rSHI"
11、说明:四表联查问题: ,#V}qSKUS
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 ..... 1#Q~aY
12、说明:日程安排提前五分钟提醒 @sPuc.
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 %M7EOa
13、说明:一条sql 语句搞定数据库分页 woyn6Z1JQ
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 ORDVyb_x
14、说明:前10条记录 |#i|BVnoE
select top 10 * form table1 where 范围 <>71;%e;'
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.) +eUWf{(_
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) i8nzPKF2$3
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 BbCaIt
(select a from tableA ) except (select a from tableB) except (select a from tableC) +{b3A@f|F
17、说明:随机取出10条数据 T8t_+|(
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select top 10 * from tablename order by newid() )&px[Dbx
18、说明:随机选择记录 3'jH,17lWV
select newid() YJm64H,[
19、说明:删除重复记录 !5^&?plC@
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) qK-\`m
20、说明:列出数据库里所有的表名 ]8o[&50y
select name from sysobjects where type='U' \c(Z?`p]R1
21、说明:列出表里的所有的 qGkD] L
select name from syscolumns where id=object_id('TableName') U32&"&";c
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。 wSPwa,)7s
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 Of gmJ(%
显示结果: x\K9|_!
type vender pcs . UaLP
电脑 A 1 'UFPQ
电脑 A 1 a<CJ#B2K
光盘 B 2 NK!#K>AO
光盘 A 2 Y'U]!c9
手机 B 3 n4A#T#D!t3
手机 C 3 /RBIZ_
23、说明:初始化表table1 pPH"6
TRUNCATE TABLE table1 ,t|qhJF
24、说明:选择从10到15的记录 Lk`,mjhk
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ~!7!Y~(+
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三、技巧 g;-6Hg'
1、1=1,1=2的使用,在SQL语句组合时用的较多 w:3CWF4q]
"where 1=1" 是表示选择全部 "where 1=2"全部不选, OhW o
如: L|y9T{s
if @strWhere !='' *-,jIaL;
begin ^@f-Ni\
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere :=oIvSnh
end IfzW%UL
else Sau?Y
begin [J\! 2\Oo
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' g!I0UAm
end <tI_u ~P
我们可以直接写成 2q}lSa7r
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere QdK
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2、收缩数据库 )\m%&EXG{
--重建索引 Lg2z `uv
DBCC REINDEX $*qQ/hi
DBCC INDEXDEFRAG I~T~!^}U
--收缩数据和日志 j}aU*p~N
DBCC SHRINKDB f\X7h6k8{
DBCC SHRINKFILE ]&_z@Z.i
3、压缩数据库 E5Zxp3 N
dbcc shrinkdatabase(dbname) P;V5f8r?
4、转移数据库给新用户以已存在用户权限 r}M2t$nv
exec sp_change_users_login 'update_one','newname','oldname' VpyqVbx1
go EXizRL-9o
5、检查备份集 uGY(`
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' LA4,o@V`
6、修复数据库 vT;~\,M
ALTER DATABASE [dvbbs] SET SINGLE_USER Cm%xI&Y
GO `%$l
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK w\%AR1,rs
GO
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ALTER DATABASE [dvbbs] SET MULTI_USER !n`Y^
GO >o4Ih^VB
7、日志清除 ,T0q.!d
SET NOCOUNT ON |wkUnn4UB8
DECLARE @LogicalFileName sysname, il~A(`+YO
@MaxMinutes INT, Jl-:@[;
@NewSize INT ,r,$x4*
USE tablename -- 要操作的数据库名 ;dquld+q
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 8],tGMu
@MaxMinutes = 10, -- Limit on time allowed to wrap log. q{2
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@NewSize = 1 -- 你想设定的日志文件的大小(M) qt=nN-AC(
-- Setup / initialize Co^GsUJ
DECLARE @OriginalSize int 0I7 r{T
SELECT @OriginalSize = size cL^r^kL("
FROM sysfiles I`uOsZBO/
WHERE name = @LogicalFileName _5H0<%\
SELECT 'Original Size of ' + db_name() + ' LOG is ' + UE 1tm
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + !~-@p?kW/
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 4%>2>5
FROM sysfiles v
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WHERE name = @LogicalFileName EeDK ^W8N
CREATE TABLE DummyTrans gT#hF]c:
(DummyColumn char (8000) not null) tE]Y=x[Ux
DECLARE @Counter INT, .*{0[
@StartTime DATETIME, f19'IH$n{
@TruncLog VARCHAR(255) >*"1`vcxF
SELECT @StartTime = GETDATE(), wj-z;YCV
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' UO}Yr8Z;
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Z3N^)j8
EXEC (@TruncLog) yv2wQ_({
-- Wrap the log if necessary. ;hCUy=m.
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired DlxL:
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Ybp';8V
AND (@OriginalSize * 8 /1024) > @NewSize pe>[Ts`2F
BEGIN -- Outer loop. &b=OT%D~FU
SELECT @Counter = 0 gn6 @x
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) C
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BEGIN -- update Fh~
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INSERT DummyTrans VALUES ('Fill Log') L%31>)8
DELETE DummyTrans J9q[u[QZ9O
SELECT @Counter = @Counter + 1 W+ v#m>G
END { v#wU
EXEC (@TruncLog) Xo
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END ^$~&e :{
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 9IJc9Sv(
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + U
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 25/M2u?
FROM sysfiles ?;ovh nY)
WHERE name = @LogicalFileName 4N_iHe5U
DROP TABLE DummyTrans g$^I/OK?
SET NOCOUNT OFF zTW)SX_O
8、说明:更改某个表 wG",Obja
exec sp_changeobjectowner 'tablename','dbo' ;C~:C^Q\H
9、存储更改全部表 MOIMW+n
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 1aS66TS3
@OldOwner as NVARCHAR(128), 4&wwmAp^
@NewOwner as NVARCHAR(128) g%%j"Cz1
AS f6JC>Np
DECLARE @Name as NVARCHAR(128) `+ 5,=S
DECLARE @Owner as NVARCHAR(128) VZCCMh-
DECLARE @OwnerName as NVARCHAR(128) K yDPD'
DECLARE curObject CURSOR FOR yN9setw*,M
select 'Name' = name, a"whg~
'Owner' = user_name(uid) DUWSY?^c
from sysobjects ;]Ko7M(4
where user_name(uid)=@OldOwner ;\rKkH"K8n
order by name hg+0!DVx
OPEN curObject }=
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FETCH NEXT FROM curObject INTO @Name, @Owner d/l>~%bR
WHILE(@@FETCH_STATUS=0) /YD2F
BEGIN ebIRXUF}>
if @Owner=@OldOwner Hi#f
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begin +~'ap'k m
set @OwnerName = @OldOwner + '.' + rtrim(@Name) o`~%}3
exec sp_changeobjectowner @OwnerName, @NewOwner }<mK79m
end z0xw0M+X
-- select @name,@NewOwner,@OldOwner C0[Z>$
FETCH NEXT FROM curObject INTO @Name, @Owner 0%;y'd**Ck
END /}R*'y
close curObject fe+2U|y
deallocate curObject 7R=A]@
GO m!^z{S
10、SQL SERVER中直接循环写入数据 qExmf%q:q
declare @i int q#*b4q
{
set @i=1 !z|a+{
while @i<30 epQdj=h
begin '<% ;Nv
insert into test (userid) values(@i) T}y@ a^#
set @i=@i+1 <BhNmEo)2
end E2yL9]K2
小记存储过程中经常用到的本周,本月,本年函数 =6< Am
Dateadd(wk,datediff(wk,0,getdate()),-1) _>(qQ-Px
Dateadd(wk,datediff(wk,0,getdate()),6) |5#iPw_wMY
Dateadd(mm,datediff(mm,0,getdate()),0) #uCE0}N@
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Ct0YwIR*
Dateadd(yy,datediff(yy,0,getdate()),0) A&7~]BR\
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ??h4qJ
上面的SQL代码只是一个时间段 WQ)vu&;
Dateadd(wk,datediff(wk,0,getdate()),-1) OQ*rxLcA
Dateadd(wk,datediff(wk,0,getdate()),6) q+cx.Rc#
就是表示本周时间段. r>;6>ZMe
下面的SQL的条件部分,就是查询时间段在本周范围内的: *;Gn od<
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) d <Rv~F@
而在存储过程中 GOj<>h}r
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ?@5#p*u0
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) =SpD6
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