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。 &uO%_6J
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一、基础 Sv +IS
1、说明:创建数据库
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CREATE DATABASE database-name Vv ?-"\Z>
2、说明:删除数据库 [Nk3|u`h
drop database dbname .,OVzW
3、说明:备份sql server +u3=dj"[
--- 创建 备份数据的 device C_7+a@?B
USE master S;)w.
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' |>#{[wko
--- 开始 备份 e:5bzk!~
BACKUP DATABASE pubs TO testBack ` eXaT8
4、说明:创建新表 MgY0q?.S=
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Y 1t\iU
根据已有的表创建新表: o}$EG
A:create table tab_new like tab_old (使用旧表创建新表) Ba!J"b]
B:create table tab_new as select col1,col2... from tab_old definition only ihfiK|a
5、说明:删除新表 hy`?E6=9+
drop table tabname ;S>])5<
6、说明:增加一个列 vMm1Z5S/
Alter table tabname add column col type K|Di1)7=/
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 Gy6l<:;
7、说明:添加主键: Alter table tabname add primary key(col) 6=fSE=]DY
说明:删除主键: Alter table tabname drop primary key(col) urjjw.wZ
8、说明:创建索引:create [unique] index idxname on tabname(col....) -&-Ma,M?
删除索引:drop index idxname #':fkIYe'
注:索引是不可更改的,想更改必须删除重新建。 BYMi6wts
9、说明:创建视图:create view viewname as select statement LRNh@g4ei
删除视图:drop view viewname
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10、说明:几个简单的基本的sql语句 vuoQz\
选择:select * from table1 where 范围 e8GEoD
插入:insert into table1(field1,field2) values(value1,value2) tV{4"Ij9[
删除:delete from table1 where 范围 OR;uqV@
更新:update table1 set field1=value1 where 范围 rv|)n>m
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! G{6;>8h
排序:select * from table1 order by field1,field2 [desc] dF2nEaN0%
总数:select count as totalcount from table1 |\7
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求和:select sum(field1) as sumvalue from table1 bp~g;h*E2
平均:select avg(field1) as avgvalue from table1 D?NbW @]
最大:select max(field1) as maxvalue from table1 lx[oaCr
最小:select min(field1) as minvalue from table1 Kq;8=xP[
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11、说明:几个高级查询运算词 Vz= PiMO
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A: UNION 运算符 +,#$:fs u
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。 p_${Nj
B: EXCEPT 运算符 Ljp%CI[i
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 w%JTTru
C: INTERSECT 运算符 fmb} 2h
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 YLiSbLz1
注:使用运算词的几个查询结果行必须是一致的。 '|Kmq5)
12、说明:使用外连接 2AO~HxF
A、left outer join: ZHm7Isa1
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 U'<KC"f:'!
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 6er-{.L=
B:right outer join: fR*q?,
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 U qFv}VsnF
C:full outer join: R'!
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 8&)DE@W
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二、提升 V;:j ZpG
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Dk(1}%0U/
法一:select * into b from a where 1<>1 iC98_o_9
法二:select top 0 * into b from a |~X ;1j!
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 9.a3&*tV[
insert into b(a, b, c) select d,e,f from b; ~e+\k>^eN
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) \ytJ=0r
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ZI 3Nq
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. :"xzj<(
4、说明:子查询(表名1:a 表名2:b) y*tZ
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select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) %0,#ADCqOe
5、说明:显示文章、提交人和最后回复时间 uFPF!Ern
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 2E)wpgUc?e
6、说明:外连接查询(表名1:a 表名2:b) d\
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c BE_ay-
7、说明:在线视图查询(表名1:a ) Y[$!`);Ye
select * from (SELECT a,b,c FROM a) T where t.a > 1; e0T34x'
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 :qIXY/
select * from table1 where time between time1 and time2 G}:lzOlMH
select a,b,c, from table1 where a not between 数值1 and 数值2 9&` 2V
9、说明:in 的使用方法 8\5 T3AF
select * from table1 where a [not] in ('值1','值2','值4','值6') o8-^cP1
10、说明:两张关联表,删除主表中已经在副表中没有的信息 |,!IZ-
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) E~gyy]8&
11、说明:四表联查问题:
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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 ..... /5:bvg+
12、说明:日程安排提前五分钟提醒 INi]R^-
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 glF; eT
13、说明:一条sql 语句搞定数据库分页 _;UE9S%
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 8_tK4PwP
14、说明:前10条记录 "vyNxZE
select top 10 * form table1 where 范围 c;n *AK
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.) s#tZg
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) j&Wl0
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 H
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(select a from tableA ) except (select a from tableB) except (select a from tableC) vWf;
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17、说明:随机取出10条数据 }` ! =
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select top 10 * from tablename order by newid() U2wbv Xr5-
18、说明:随机选择记录 L G1r]2
select newid() iMP]W_
19、说明:删除重复记录 1PP $XJtyD
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) WUsKnf
20、说明:列出数据库里所有的表名 /O^RF }
select name from sysobjects where type='U' thvYL.U:
21、说明:列出表里的所有的 2h=!k|6
select name from syscolumns where id=object_id('TableName') rjP L+T_
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 +[tE ^`-F
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type vOc 9ZE
显示结果: \u>"s
type vender pcs )l[M
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电脑 A 1 }woo%N P
电脑 A 1 N0=ac5
光盘 B 2 T|dY
2
光盘 A 2 eQD)$d_5
手机 B 3 0 rXx RQ
手机 C 3 y?a
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23、说明:初始化表table1 X90J!
TRUNCATE TABLE table1 :h&fbBH
24、说明:选择从10到15的记录 (s7;^)}zx
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc [I$BmGQ
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三、技巧 >9(hUH
1、1=1,1=2的使用,在SQL语句组合时用的较多 Mc%Nf$XQ
"where 1=1" 是表示选择全部 "where 1=2"全部不选, =|%Cu&
如: (
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if @strWhere !='' -xDGH
begin `}lJH i
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere
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end _&j}<K$-(
else ,Td!|~I|j6
begin '`XX
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' kWe{r5C7
end ni6{pK4Wqm
我们可以直接写成 ,^x4sA[/
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere H*Kj3NgY
2、收缩数据库 -t2+|J*
--重建索引 Ircp``g
DBCC REINDEX K a6,<C
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DBCC INDEXDEFRAG sm\f0P!rv
--收缩数据和日志 niqN{
DBCC SHRINKDB &/uu)v
DBCC SHRINKFILE eOXHQjuj
3、压缩数据库 ;B?DfWX
dbcc shrinkdatabase(dbname) O=$~O\}b
4、转移数据库给新用户以已存在用户权限 VA9Gb9
exec sp_change_users_login 'update_one','newname','oldname' Yb/i{@AJ
go >layJt
5、检查备份集 ??i,Vr@)w
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ;[W"mlM
6、修复数据库 +\|Iu;w
ALTER DATABASE [dvbbs] SET SINGLE_USER @~#Ym1{W
GO lK4M.QV
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK -,+q#F
GO u6_@.a}
ALTER DATABASE [dvbbs] SET MULTI_USER "7v @Rye
GO UY <e&Npo
7、日志清除 o.'g]Q<}UB
SET NOCOUNT ON
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DECLARE @LogicalFileName sysname, K\$J4~EtG
@MaxMinutes INT, .'rW.'Ft
@NewSize INT `"@g8PWe
USE tablename -- 要操作的数据库名 v k?skN@
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 #~=hn8
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ~>:Z6Le@
@NewSize = 1 -- 你想设定的日志文件的大小(M) \igmv]G%
-- Setup / initialize rS?pWTg"8
DECLARE @OriginalSize int ^kgBa2 7
SELECT @OriginalSize = size 2l
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FROM sysfiles 9&2Vm;F_
WHERE name = @LogicalFileName q~59F@
SELECT 'Original Size of ' + db_name() + ' LOG is ' + J%jB?2
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + OKP9CLg9
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 8> .J1C
FROM sysfiles "n: %E
WHERE name = @LogicalFileName v0kqu
CREATE TABLE DummyTrans sj8~?O
(DummyColumn char (8000) not null) 0z[dlHi
DECLARE @Counter INT, d~?X/sJ t
@StartTime DATETIME, `iJhG^w9M
@TruncLog VARCHAR(255) NFr:y<0>z
SELECT @StartTime = GETDATE(), Kv rX{F=
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' $rhgzpZ!X_
DBCC SHRINKFILE (@LogicalFileName, @NewSize) AxZD-|.
EXEC (@TruncLog) T /mI[*1xI
-- Wrap the log if necessary. [Cb`{
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 7]BW[~77
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) o d7]tOK9
AND (@OriginalSize * 8 /1024) > @NewSize cDoo*
BEGIN -- Outer loop. 2o9$4{}rG
SELECT @Counter = 0 O$g_@B0E1
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) N,J9Wu ZJ\
BEGIN -- update K9kUS
INSERT DummyTrans VALUES ('Fill Log') 3-%Cw2ds
DELETE DummyTrans 9M /SH$Qy
SELECT @Counter = @Counter + 1 Pa^A$fy\
END ?|1Mv1C?
EXEC (@TruncLog) ';G1A
END 0vGyI>
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 6ATtW+sN ]
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 3loY qeP
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' |T4kqW{
FROM sysfiles $fpq
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WHERE name = @LogicalFileName !~ZP{IXyo
DROP TABLE DummyTrans r{seb E\
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SET NOCOUNT OFF }6-ZE9H-v
8、说明:更改某个表 g2R@`./S
exec sp_changeobjectowner 'tablename','dbo' !'f3>W\
9、存储更改全部表 2`a
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch @+Y8*Rj\3
@OldOwner as NVARCHAR(128), ,SScf98,j
@NewOwner as NVARCHAR(128) >qo~d?+
AS &48_2Q"{
DECLARE @Name as NVARCHAR(128) e.o;eD}"
DECLARE @Owner as NVARCHAR(128) MqKye8h9f
DECLARE @OwnerName as NVARCHAR(128) Zw]
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DECLARE curObject CURSOR FOR Qpt&3_
select 'Name' = name, >~\w+^2f8
'Owner' = user_name(uid) @ 2_<,;$
from sysobjects ue8qIZH
where user_name(uid)=@OldOwner nPkZHIxuD
order by name CkRX>)=py
OPEN curObject x3e]d$
FETCH NEXT FROM curObject INTO @Name, @Owner 8V$3b?]
WHILE(@@FETCH_STATUS=0) 3,);0@I
BEGIN DJQglt}~
if @Owner=@OldOwner np WEop>
begin uO >x:*^8
set @OwnerName = @OldOwner + '.' + rtrim(@Name) Ae?e 70bY
exec sp_changeobjectowner @OwnerName, @NewOwner S*)o)34U
end z}.D"
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-- select @name,@NewOwner,@OldOwner M0-,M/]l
FETCH NEXT FROM curObject INTO @Name, @Owner XNH4==4
END qd!#t]
close curObject (tl}q3U
deallocate curObject ex?\c"
GO hN(L@0)
10、SQL SERVER中直接循环写入数据 L"rcv:QWZa
declare @i int agd)ag4"[u
set @i=1 i~& c|
while @i<30 w}M3x^9@
begin j[P8
insert into test (userid) values(@i) PaVO"y]C
set @i=@i+1 ,.g}W~S)
end G^Xd- 7 GQ
小记存储过程中经常用到的本周,本月,本年函数 R I@*O6\/I
Dateadd(wk,datediff(wk,0,getdate()),-1) 74zSP/G'
Dateadd(wk,datediff(wk,0,getdate()),6) ;IC'Gq
Dateadd(mm,datediff(mm,0,getdate()),0) >;i\v7
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) F@hYA
Dateadd(yy,datediff(yy,0,getdate()),0) JJl7JwSTW
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) A/Khk2-:
上面的SQL代码只是一个时间段 )o8g=7Jm
Dateadd(wk,datediff(wk,0,getdate()),-1) lIuXo3
Dateadd(wk,datediff(wk,0,getdate()),6) 8Z:Ezg3^
就是表示本周时间段. 6.Bh3p
下面的SQL的条件部分,就是查询时间段在本周范围内的: B
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) >QI~`MiI
而在存储过程中 pN$;!
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 55hyV{L%
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) IT1PPm