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。 0Un?[O
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一、基础 |W_;L6)
1、说明:创建数据库 ORuC("
CREATE DATABASE database-name K*I!:1;3N
2、说明:删除数据库 /9ctmW1!<
drop database dbname U}@xMt8@l
3、说明:备份sql server ZP{<f~;
--- 创建 备份数据的 device +`,;tz=?
USE master `>)[UG!:|
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 2Pow-o*r
--- 开始 备份 ~jC+6v
BACKUP DATABASE pubs TO testBack ];xDXQd
4、说明:创建新表 e[
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 1r$*8|p
根据已有的表创建新表: bd]9kRq1K
A:create table tab_new like tab_old (使用旧表创建新表) .DNPL5[v
B:create table tab_new as select col1,col2... from tab_old definition only !]5}N^X
5、说明:删除新表 !7Eodq-0
drop table tabname ;/:Sx/#s
6、说明:增加一个列 5`Q j<
Alter table tabname add column col type c+D<
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 wXjidOd$
7、说明:添加主键: Alter table tabname add primary key(col) \?Sv O
说明:删除主键: Alter table tabname drop primary key(col) e, N}z
8、说明:创建索引:create [unique] index idxname on tabname(col....) \~RDvsSD
删除索引:drop index idxname WP2=1"X63
注:索引是不可更改的,想更改必须删除重新建。 G/*;h,NbNr
9、说明:创建视图:create view viewname as select statement 8Cs;.>75[
删除视图:drop view viewname .7]P-]uOZ
10、说明:几个简单的基本的sql语句 G %'xEr0n
选择:select * from table1 where 范围 L!>nl4O>`
插入:insert into table1(field1,field2) values(value1,value2) m _cRK}>
删除:delete from table1 where 范围 28k=@k^q
更新:update table1 set field1=value1 where 范围 CP~mKmMV
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! &&nbdu
排序:select * from table1 order by field1,field2 [desc] 4
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总数:select count as totalcount from table1 2n)?)w]!M
求和:select sum(field1) as sumvalue from table1 _f'v>"K
平均:select avg(field1) as avgvalue from table1 85YUqVi9
最大:select max(field1) as maxvalue from table1 84vd~Cf9
最小:select min(field1) as minvalue from table1
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11、说明:几个高级查询运算词 c/Xg ARCO
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A: UNION 运算符 9 w$m\nV
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 =:aJZ[UU<2
B: EXCEPT 运算符 w
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EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 T'9ZR,{F
C: INTERSECT 运算符 ak7kb7 5o
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 XeX"IhgS>E
注:使用运算词的几个查询结果行必须是一致的。 jUE gu
12、说明:使用外连接 MB!9tju
A、left outer join: zcKQD )]
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 rUpe ;c
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c baBBn%_V
B:right outer join: W#S8 2
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 l% T4:p4e
C:full outer join: RWc<CQcL"
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 #~!"`B?#*
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二、提升 I]^>>>p$
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) L8 L1_
法一:select * into b from a where 1<>1 4q E95THB
法二:select top 0 * into b from a <q8@a0e@
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) q pCI[[
insert into b(a, b, c) select d,e,f from b; )\|+G5#`
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) ]QhTxrF"
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 W7^[W.
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 5BJE
4、说明:子查询(表名1:a 表名2:b) -~mgct5
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) $#q`Y+;L2
5、说明:显示文章、提交人和最后回复时间 #L~i|(=U5
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 1h&`mqY)L.
6、说明:外连接查询(表名1:a 表名2:b) IdQ./@?
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c X/yq<_ g
7、说明:在线视图查询(表名1:a ) p&h?p\IF
select * from (SELECT a,b,c FROM a) T where t.a > 1; N ~{N Nf Y
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 lG}#K^q
select * from table1 where time between time1 and time2 H/c
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select a,b,c, from table1 where a not between 数值1 and 数值2 ]3rVULU"K-
9、说明:in 的使用方法 ")T\_ME
select * from table1 where a [not] in ('值1','值2','值4','值6') LWyr
10、说明:两张关联表,删除主表中已经在副表中没有的信息 g w"
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) .!x&d4;,q
11、说明:四表联查问题: fbNzRXw
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 ..... !R=@Nr>
12、说明:日程安排提前五分钟提醒 M2O_kOeZ
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 unLhI0XW
13、说明:一条sql 语句搞定数据库分页 TIWR[r1!
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 (k?HT'3)
14、说明:前10条记录 Mf1(4F
select top 10 * form table1 where 范围 d~Z\%4
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.) b6bs .
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) yO q@w!xz
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 ;f[lq^eV
(select a from tableA ) except (select a from tableB) except (select a from tableC) E5w;75,
17、说明:随机取出10条数据 9af.t
select top 10 * from tablename order by newid() <Dd>- K
18、说明:随机选择记录 O`B,mgT(
select newid() <h/%jM>9/
19、说明:删除重复记录 {~3QBMx6
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) `7CK;NeT
20、说明:列出数据库里所有的表名 jN\u}!\O
select name from sysobjects where type='U' Cf
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21、说明:列出表里的所有的 -L1785pB85
select name from syscolumns where id=object_id('TableName') T3X'73M
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。 +(W1x
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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 FJ:^pROpm
显示结果: ']r8q %
type vender pcs pk :P;\
电脑 A 1 WMSJU/-P
电脑 A 1 KJA
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光盘 B 2 v1.3gzR
光盘 A 2 g8W,Xq+
手机 B 3 DxJ;C09xNa
手机 C 3 XBQt:7[<
23、说明:初始化表table1 Yc:%2KZ"
TRUNCATE TABLE table1 (N7uaZ?Z
24、说明:选择从10到15的记录 CL|/I:%0
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc c$O8Rhx
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三、技巧 LQ jbEYp
1、1=1,1=2的使用,在SQL语句组合时用的较多 d$zJLgkA
"where 1=1" 是表示选择全部 "where 1=2"全部不选, eTiTS*`u
如: o*S_"
if @strWhere !='' \^x{NV@v42
begin xN 1P#
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere O
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end ,/42^|=Z6O
else L*6'u17y
begin rbZbj#
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' =V^-@ji)b
end
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我们可以直接写成 -V2\s
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere N3%X>*'
2、收缩数据库 @(3F4Z.i%.
--重建索引 >f(?Mxh2
DBCC REINDEX k }=<51c
DBCC INDEXDEFRAG Dac)`/
--收缩数据和日志 b 7UJ
DBCC SHRINKDB z
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DBCC SHRINKFILE i"^> sk
3、压缩数据库 T] zEcx+e
dbcc shrinkdatabase(dbname) %FO{:@CH
4、转移数据库给新用户以已存在用户权限 r|Ui1f5
exec sp_change_users_login 'update_one','newname','oldname' (}: s[cs
go . %RM8
5、检查备份集 b)LT[>f
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' f7Gn$E|/r;
6、修复数据库 d1b]+A G4
ALTER DATABASE [dvbbs] SET SINGLE_USER ;cor\R
GO =!q%
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK |>.Q U3
GO oQ$yr^M
ALTER DATABASE [dvbbs] SET MULTI_USER p0+^wXi)
GO bSB%hFp=Cp
7、日志清除 SmRlZ!%e
SET NOCOUNT ON 4,9$udiGY
DECLARE @LogicalFileName sysname, 6Sr]<I +:
@MaxMinutes INT, * {g3ia
@NewSize INT 3H,E8>Vd
USE tablename -- 要操作的数据库名 jvzioFCt
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 W(, j2pU
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 3/G^V'Yu
@NewSize = 1 -- 你想设定的日志文件的大小(M) bsIG1&n'T
-- Setup / initialize YH&=cI@
DECLARE @OriginalSize int z/@_?01T=
SELECT @OriginalSize = size }A#IBqf5
FROM sysfiles 2hh8G5IaQ
WHERE name = @LogicalFileName hXW` n*Zw
SELECT 'Original Size of ' + db_name() + ' LOG is ' + /%wS5IZ^
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + |Splbsk
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' %opBJ
FROM sysfiles 5/meH[R\M
WHERE name = @LogicalFileName Ve,g9 I
CREATE TABLE DummyTrans !"<[&
(DummyColumn char (8000) not null) L P<A q
DECLARE @Counter INT, ^h(wi`i
@StartTime DATETIME, zLI0RI.Pe
@TruncLog VARCHAR(255) _Nx
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SELECT @StartTime = GETDATE(), e#"h@kZP
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' +#O+%!
DBCC SHRINKFILE (@LogicalFileName, @NewSize) aeqz~z2~8s
EXEC (@TruncLog) VYvfx
-- Wrap the log if necessary. 1!#85SMx
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired %y1!'R:ZW
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 55[ 4)*
AND (@OriginalSize * 8 /1024) > @NewSize t@q'm.:uw<
BEGIN -- Outer loop. +H)'(<
SELECT @Counter = 0 YeH!v, >
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 7_0p& 3
BEGIN -- update |)-kUu
INSERT DummyTrans VALUES ('Fill Log') vOQ%f?%G\
DELETE DummyTrans @Nu2
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SELECT @Counter = @Counter + 1 Z;BS@e
END |P|B"I<?
EXEC (@TruncLog) Bo 35L:r|
END PwY/VGT
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 'ofj1%c
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + v^|U?
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' U|^xr~q!f-
FROM sysfiles $=aO*i
WHERE name = @LogicalFileName g=*jKSZ
DROP TABLE DummyTrans 5&]5*;Bv J
SET NOCOUNT OFF 3h:j.8Z
8、说明:更改某个表 =ily=j"hK
exec sp_changeobjectowner 'tablename','dbo' 20:F$d
9、存储更改全部表 IqOg{#sm
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch .sMs_ 5D
@OldOwner as NVARCHAR(128), u9lZHh#V-
@NewOwner as NVARCHAR(128) Fq9YhR
AS 8@3K, [Mo
DECLARE @Name as NVARCHAR(128) sI ,!+
DECLARE @Owner as NVARCHAR(128) iD^,O)b
DECLARE @OwnerName as NVARCHAR(128) Jt~Ivn,
DECLARE curObject CURSOR FOR rK3kg2H
select 'Name' = name, 3jmo[<p*x
'Owner' = user_name(uid) .@1+}0
from sysobjects q=1 NRG
where user_name(uid)=@OldOwner uuzV,q
order by name N& _~y|
OPEN curObject Z6!Up1
FETCH NEXT FROM curObject INTO @Name, @Owner fFQ|dE;cF
WHILE(@@FETCH_STATUS=0) TlG>)Z@/
BEGIN N&9o 1_}
if @Owner=@OldOwner T j$'B[cv
begin !avol/*
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 9&mSF0q
exec sp_changeobjectowner @OwnerName, @NewOwner bO~y=Pa\
end mHD_cgKN
-- select @name,@NewOwner,@OldOwner WT
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FETCH NEXT FROM curObject INTO @Name, @Owner R@e'=z[%1
END 8K%N7RL|
close curObject G0FzXtu)q
deallocate curObject }nmlN
GO 2YD\KXDo
10、SQL SERVER中直接循环写入数据 iFI74COam
declare @i int
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set @i=1 x*7@b8J
while @i<30 Q>niJ'7WF
begin j,IRUx13f
insert into test (userid) values(@i) !MbzFs~
set @i=@i+1 [%W'd9`>
end 86&M Zdv6
小记存储过程中经常用到的本周,本月,本年函数 KK|w30\f
Dateadd(wk,datediff(wk,0,getdate()),-1) 1wSAwpz
Dateadd(wk,datediff(wk,0,getdate()),6) \Z{tC$|H
Dateadd(mm,datediff(mm,0,getdate()),0) uvys>]+
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) z^Hc'oVXj:
Dateadd(yy,datediff(yy,0,getdate()),0) \#sD`O
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 05UN
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上面的SQL代码只是一个时间段 5_yQI D%Sq
Dateadd(wk,datediff(wk,0,getdate()),-1) TnW`#.f
Dateadd(wk,datediff(wk,0,getdate()),6) Vk5Z[w a
就是表示本周时间段. C@M-_Ud>Q
下面的SQL的条件部分,就是查询时间段在本周范围内的: X>(1fra4
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ,67Q!/O
而在存储过程中 A40DbD\^ad
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) >e]g T
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) o3WOp80hz