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。 `>0MNmu
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一、基础 A+6 n#
1、说明:创建数据库 \drqG&wl
CREATE DATABASE database-name qmO6,T-|
2、说明:删除数据库 @1*ohdHH
drop database dbname 8Ac)'2t;U
3、说明:备份sql server Bm&kkx.9P
--- 创建 备份数据的 device 3_~cMlr3T.
USE master yjfat&$
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ~\{^%~[48
--- 开始 备份 *Qugv^-
BACKUP DATABASE pubs TO testBack ~U;rw&'H
4、说明:创建新表 5N%93{L
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) hxCvk/7sT
根据已有的表创建新表: }*.0N;;C
A:create table tab_new like tab_old (使用旧表创建新表) 'YNT8w/3
B:create table tab_new as select col1,col2... from tab_old definition only ^Wxad?@
5、说明:删除新表 >:D
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drop table tabname GpZc5c
6、说明:增加一个列 !Mi;*ZR
Alter table tabname add column col type 64hk2a8
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。 Q+g!V5'
7、说明:添加主键: Alter table tabname add primary key(col) b
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说明:删除主键: Alter table tabname drop primary key(col) (Qa/EkE^*w
8、说明:创建索引:create [unique] index idxname on tabname(col....) Cmc3k,t
删除索引:drop index idxname foJdu+^
注:索引是不可更改的,想更改必须删除重新建。 \
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9、说明:创建视图:create view viewname as select statement sR/b$j>i3
删除视图:drop view viewname O'Js}
10、说明:几个简单的基本的sql语句 W6On93sa
选择:select * from table1 where 范围 9Xx's%U
插入:insert into table1(field1,field2) values(value1,value2) m(pE5B(
删除:delete from table1 where 范围 EwOV;>@T?
更新:update table1 set field1=value1 where 范围 V(Ub!n:j
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! K|dso]b/
排序:select * from table1 order by field1,field2 [desc] w@N
总数:select count as totalcount from table1 h;6lK$!c
求和:select sum(field1) as sumvalue from table1 y|'SXM
平均:select avg(field1) as avgvalue from table1 } CeCc0M
最大:select max(field1) as maxvalue from table1 LX^u_Iu
最小:select min(field1) as minvalue from table1 u_ABt?'
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11、说明:几个高级查询运算词 [Q=dCX9%
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A: UNION 运算符 _YF%V;X
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。 qUly\b 47
B: EXCEPT 运算符 ^tXJj:wtS
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。 &hRvol\J
C: INTERSECT 运算符 .A6(D$O k
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 K)J(./
注:使用运算词的几个查询结果行必须是一致的。 =JJL[}a|
12、说明:使用外连接 ULQMG'P^D
A、left outer join: hWX% 66
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 )B[0JrcE
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c HD(.BW7
B:right outer join: "HPB!)C8(
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 s`0QA!G{-
C:full outer join: rF]h$Z8o
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。 o865(<p
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二、提升 3YVi"
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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) -|E!e.^7:
法一:select * into b from a where 1<>1 ;VWAf;U;B
法二:select top 0 * into b from a $sEy%-
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 'Fmvu
insert into b(a, b, c) select d,e,f from b; ?Wz8[u
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) e o pD5
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 L'F<ev
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. {?yr'*
4、说明:子查询(表名1:a 表名2:b) Hla0 5N' 4
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) s0PrbL%_`
5、说明:显示文章、提交人和最后回复时间 ^Vpq$'!
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b i9/aAH0
6、说明:外连接查询(表名1:a 表名2:b) nw-I|PVTNa
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ]C) 4
7、说明:在线视图查询(表名1:a ) J>\B`E
select * from (SELECT a,b,c FROM a) T where t.a > 1; 92EWIHEWZ
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 Z?\2F%
select * from table1 where time between time1 and time2 p\bDY
select a,b,c, from table1 where a not between 数值1 and 数值2 ~$~5qwl
9、说明:in 的使用方法 p\<u6v ~J
select * from table1 where a [not] in ('值1','值2','值4','值6') Nqu>6^-z0
10、说明:两张关联表,删除主表中已经在副表中没有的信息 }K&7%N4LZ
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) kXf'5p1
11、说明:四表联查问题: ]w.;4`l*
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... 78/Zk}I]
12、说明:日程安排提前五分钟提醒 [D!jv"
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ~c&bH]cj
13、说明:一条sql 语句搞定数据库分页 bFW =ylF9
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 m@^1JlH
14、说明:前10条记录 DCZ\6WY1G)
select top 10 * form table1 where 范围 %@u;5qD&
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) Sv +IS
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b)
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16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 p>upA)W]
(select a from tableA ) except (select a from tableB) except (select a from tableC) d!$Z(W0
17、说明:随机取出10条数据 7k rUKYVo
select top 10 * from tablename order by newid() Z:*76PP,
18、说明:随机选择记录 <N%7|t*eT
select newid() l6d$V9A
19、说明:删除重复记录 wYmM"60
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) /AW=5Ck- #
20、说明:列出数据库里所有的表名 ;UfCj5`Q)4
select name from sysobjects where type='U' Z-l=\ekJ
21、说明:列出表里的所有的 PS[+~>%
select name from syscolumns where id=object_id('TableName') mFi&YpHu3
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 S;)w.
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type 6Aku1h
显示结果: tQjLOv+?=
type vender pcs } q$ WvY/
电脑 A 1 =F@Wgn,
电脑 A 1 LbkF
光盘 B 2 GSRVe/[
光盘 A 2 Pqn@ST
手机 B 3 T87m?a$
手机 C 3 D ^x-^6^
23、说明:初始化表table1 >M`CVUf
TRUNCATE TABLE table1 bdc&1I$
24、说明:选择从10到15的记录 ;LMJd@
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ihfiK|a
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三、技巧 2'W<h)m)z
1、1=1,1=2的使用,在SQL语句组合时用的较多 >Vwc3d
"where 1=1" 是表示选择全部 "where 1=2"全部不选, hK_LEwd;
如: aP/T<QZ~
if @strWhere !='' rsy'q(N[
begin hUF5fZqii
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ~FN9 [aJF+
end ,.7*Hpa
else fe9LEM8j
begin hX=A)73(
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' +Nt2
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end LRNh@g4ei
我们可以直接写成 9;B0Mq
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere iy%ZQ[Un
2、收缩数据库 dfij|>:*0
--重建索引 8]U{;|';
DBCC REINDEX J{k79v
DBCC INDEXDEFRAG -$dXE+&
--收缩数据和日志 e=+?K5q{P(
DBCC SHRINKDB Y4v|ko`l%
DBCC SHRINKFILE )s%[T-uKi
3、压缩数据库 o}* hY"&
dbcc shrinkdatabase(dbname) MpF$xzh
4、转移数据库给新用户以已存在用户权限 %y@Hh=
exec sp_change_users_login 'update_one','newname','oldname' p{j.KI s7
go [m|YWT=
5、检查备份集 .n~M(59
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Np"exFqN k
6、修复数据库 j'HZ\_
ALTER DATABASE [dvbbs] SET SINGLE_USER 70eb]\%
GO R~S;sJ& c
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Z\k&gio5C^
GO \Hn>oonph
ALTER DATABASE [dvbbs] SET MULTI_USER lx[oaCr
GO ,"HL~2:~
7、日志清除 ;N0~;I
SET NOCOUNT ON _Nqt21sL
DECLARE @LogicalFileName sysname, /K.!sQ$
@MaxMinutes INT, r(RKwr:m
@NewSize INT 6I4oi@hZz
USE tablename -- 要操作的数据库名 '2[albxSc
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 @
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. n6BQk2l
@NewSize = 1 -- 你想设定的日志文件的大小(M) Y\$ySvZ0
-- Setup / initialize s=0BMPDgm
DECLARE @OriginalSize int XBp? w
SELECT @OriginalSize = size *q-['"f
FROM sysfiles ' <@3i[M
WHERE name = @LogicalFileName SUU !7Yd|
SELECT 'Original Size of ' + db_name() + ' LOG is ' + N _86t
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + H*$jc\
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' d'G0m9u2
FROM sysfiles 6jC`8l:
WHERE name = @LogicalFileName Bg|5KOnd
CREATE TABLE DummyTrans Aj+2;]M
(DummyColumn char (8000) not null) V 7Ek-2M
DECLARE @Counter INT, 5'X ]k@m_
@StartTime DATETIME, K*X_FJ
@TruncLog VARCHAR(255) P_Gw-`L5T
SELECT @StartTime = GETDATE(),
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' -UOj>{-
DBCC SHRINKFILE (@LogicalFileName, @NewSize) d~JKH&x<
EXEC (@TruncLog) i;_t I#:A
-- Wrap the log if necessary. ZHm7Isa1
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired }MH0L#Tu
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) R]RZq+2^
AND (@OriginalSize * 8 /1024) > @NewSize qa0 yg8,<
BEGIN -- Outer loop. $>u*}X9
SELECT @Counter = 0 Yd#/1!A7u
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) {l/-LZ.
BEGIN -- update hHT_V2*
INSERT DummyTrans VALUES ('Fill Log') .ZJRO>S
DELETE DummyTrans 7aQc=^vaZ
SELECT @Counter = @Counter + 1 +h r@#n4A
END x6e}( &p*
EXEC (@TruncLog) RM!<8fXYD
END 5a hVeY
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ;;:-l99
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Wb?8j M
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' &QGdLXOn
FROM sysfiles b"vv>Q~U
WHERE name = @LogicalFileName !3*(N8_|#
DROP TABLE DummyTrans mg$]QnbAnH
SET NOCOUNT OFF Dk(1}%0U/
8、说明:更改某个表 \kU &^Hi
exec sp_changeobjectowner 'tablename','dbo' {ZI)nQ{
9、存储更改全部表 f;x kT
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch y&?6FY
@OldOwner as NVARCHAR(128), C'o64+W^
@NewOwner as NVARCHAR(128)
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AS K0}pi+=
DECLARE @Name as NVARCHAR(128) cM$P`{QrM
DECLARE @Owner as NVARCHAR(128) ]Zyur`
DECLARE @OwnerName as NVARCHAR(128) dAkgR~
DECLARE curObject CURSOR FOR 8(~K~q[Cr
select 'Name' = name, /7t>TYip!
'Owner' = user_name(uid) ](wvu(y\E
from sysobjects eFL=G%
where user_name(uid)=@OldOwner xx{PespNt
order by name O4^8jK}
OPEN curObject |Y [wzDYV
FETCH NEXT FROM curObject INTO @Name, @Owner d+Ek%_
WHILE(@@FETCH_STATUS=0) T^~5n6
BEGIN zY"1drE> G
if @Owner=@OldOwner @M5#S7q";
begin pJt,9e6
set @OwnerName = @OldOwner + '.' + rtrim(@Name) JSTuXW
exec sp_changeobjectowner @OwnerName, @NewOwner .2v_H5<
end *U]V@;XF
-- select @name,@NewOwner,@OldOwner ^w c"&;=c|
FETCH NEXT FROM curObject INTO @Name, @Owner EuyXgK>g
END /q5v"iX]T
close curObject 37|&?||
deallocate curObject 3~S8!nx
GO EioB%f3
10、SQL SERVER中直接循环写入数据 9&` 2V
declare @i int b/{t|io{
set @i=1 .tzG_
while @i<30 hR
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begin [5+}rwm&W
insert into test (userid) values(@i) a+!tT!g&I
set @i=@i+1 7lBAxqr2
end 7w/4QiI
小记存储过程中经常用到的本周,本月,本年函数 pnbIiyV
Dateadd(wk,datediff(wk,0,getdate()),-1) fDvl/|62{
Dateadd(wk,datediff(wk,0,getdate()),6) Db1pW=66:
Dateadd(mm,datediff(mm,0,getdate()),0) '{V0M<O
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ?Vf o+a,
Dateadd(yy,datediff(yy,0,getdate()),0) Q^e}?v%=%3
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 6T#+V37
上面的SQL代码只是一个时间段 -Ty*aov
Dateadd(wk,datediff(wk,0,getdate()),-1) al9t^
Dateadd(wk,datediff(wk,0,getdate()),6) zN:K%AiGxe
就是表示本周时间段. f^"N!f a
下面的SQL的条件部分,就是查询时间段在本周范围内的: aW`Lec{.
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) c;n *AK
而在存储过程中 t<|NLk.
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) MgNU``
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 6Qy@UfB