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。 8js1m55KT
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一、基础 [;C*9Nl
1、说明:创建数据库 5S! !@P!,
CREATE DATABASE database-name (x[z=_I%`
2、说明:删除数据库 p@YbIn
drop database dbname ]*rK;
3、说明:备份sql server &x4|!"G
--- 创建 备份数据的 device 9PR?'X;4
USE master py/#h$eY
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' N71%l
--- 开始 备份 k <LFH(
BACKUP DATABASE pubs TO testBack A22'qgKm@
4、说明:创建新表 dP/1E6*m
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) YO.+06X
根据已有的表创建新表: 99Nm? $g
A:create table tab_new like tab_old (使用旧表创建新表) `qy@Qo
B:create table tab_new as select col1,col2... from tab_old definition only Q,o"[ &Gp
5、说明:删除新表 f Lns^
drop table tabname UtB~joaR
6、说明:增加一个列 ) @f6
Alter table tabname add column col type SUoUXh^!w
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。 @w,O1Xwj
7、说明:添加主键: Alter table tabname add primary key(col) &X}i%etp^2
说明:删除主键: Alter table tabname drop primary key(col) N/B-u)?\:
8、说明:创建索引:create [unique] index idxname on tabname(col....) O
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删除索引:drop index idxname baR*4{]
注:索引是不可更改的,想更改必须删除重新建。 V9D>Xh!0H
9、说明:创建视图:create view viewname as select statement ,V+,3TT
删除视图:drop view viewname j;&su=p"
10、说明:几个简单的基本的sql语句 /yO0Z1G
选择:select * from table1 where 范围 H$3:Ra+ S
插入:insert into table1(field1,field2) values(value1,value2) _/}/1/y$Y
删除:delete from table1 where 范围 io$fL_R=
更新:update table1 set field1=value1 where 范围 $viZ[Lu!m
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! yzL6oU-{&
排序:select * from table1 order by field1,field2 [desc] 3gs7Xj%N
总数:select count as totalcount from table1 Gl>*e|}
求和:select sum(field1) as sumvalue from table1 JjH141 n%D
平均:select avg(field1) as avgvalue from table1 &UX:KW`=
最大:select max(field1) as maxvalue from table1 \2 `|eo
最小:select min(field1) as minvalue from table1 ]RI+:f
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11、说明:几个高级查询运算词 '!XVz$C
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A: UNION 运算符 =zwn3L8 fL
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。 yRldPk_
B: EXCEPT 运算符 _VLA2#V>
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。 !='L `.
C: INTERSECT 运算符 AbOF/g)C
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。 -pm%F8{T]
注:使用运算词的几个查询结果行必须是一致的。 >+ku:<Hw%.
12、说明:使用外连接 ys}I~MK -
A、left outer join: EpH\;25u
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。 z CFXQi
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 {bO
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B:right outer join: |Y;[)s =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。 >B+!fi'SS>
C:full outer join: B5/"2i
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。 *skmTioj&
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二、提升 t``q_!s}F
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) "VQ7Y`,+
法一:select * into b from a where 1<>1 ,uCgC4EP
法二:select top 0 * into b from a ;0:[X+"(
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 5P![fX|5
insert into b(a, b, c) select d,e,f from b; v4X)R
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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) yz^Rm2$f9
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件
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例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. @*5(KIeeC>
4、说明:子查询(表名1:a 表名2:b) /NFm6AA]
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) q3/ 0xN+?
5、说明:显示文章、提交人和最后回复时间 *L#\#nh7
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b /zIUYY
6、说明:外连接查询(表名1:a 表名2:b) OCbwV7q:
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c }6 MoC0
7、说明:在线视图查询(表名1:a ) wp>L}!
select * from (SELECT a,b,c FROM a) T where t.a > 1; |aS272'
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 G57c 8}\4
select * from table1 where time between time1 and time2 h~u|v[@{J
select a,b,c, from table1 where a not between 数值1 and 数值2 d&t,^Hj
9、说明:in 的使用方法 Fz@9
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select * from table1 where a [not] in ('值1','值2','值4','值6') $3^Cp_p6
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ix_&<?8
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ~qezr\$2
11、说明:四表联查问题: CjUYwAy$k
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 ..... Yp;?Zq9
12、说明:日程安排提前五分钟提醒 7Nlk:f)*-
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 >AUzsQ
13、说明:一条sql 语句搞定数据库分页 %<^j=K= 0
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 A\)~y{9bQ
14、说明:前10条记录 ({WV<T&
select top 10 * form table1 where 范围 4~z-&>%
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.) H[U"eS."
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) NWII?X#T}
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 L_R(K89w
(select a from tableA ) except (select a from tableB) except (select a from tableC) o'|B|oZ
17、说明:随机取出10条数据 a<lDT_2b
select top 10 * from tablename order by newid() z?'z{+HY
18、说明:随机选择记录 "g&hsp+i"A
select newid() i^"!"&tW#
19、说明:删除重复记录 Nh"U~zlh
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) g0:{{w
20、说明:列出数据库里所有的表名 m,PiuR>
select name from sysobjects where type='U' Ex@o&j\93
21、说明:列出表里的所有的 Mk!bmFZOZ
select name from syscolumns where id=object_id('TableName') #]@|mf
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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。 zAH6SaI$
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 Y@2yV(m)o
显示结果: -nDY3$U/
type vender pcs z^\-x9vL
电脑 A 1 8Cw3b\ne
电脑 A 1 4XIc|a Aa
光盘 B 2 9G^gI}bY
光盘 A 2 ZMO ym=
手机 B 3 YZ^mH <
手机 C 3 40HhMTZ0-
23、说明:初始化表table1 W7"UhM
TRUNCATE TABLE table1 )w,<XJhg`
24、说明:选择从10到15的记录 p;.M.
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc :?SD#Vvrh.
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三、技巧 *g[MGyF"
1、1=1,1=2的使用,在SQL语句组合时用的较多 Cm;M;
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, &6nLnMF8x
如: nfksi``Vq
if @strWhere !='' t
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begin 3>mAZZL5[
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere j?1wP6/NP
end >Et~h65d5
else LpN3cy>U
begin ;Pe=cc"@
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' |G/WS0
end +P%k@w#<Z
我们可以直接写成 !TO+[g!
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere z['2
2、收缩数据库 D 3Tqk^5
--重建索引 rG3?Z^&R+
DBCC REINDEX moL3GV%]Gq
DBCC INDEXDEFRAG AejM\#>
--收缩数据和日志 y+nX(@~f]
DBCC SHRINKDB YFP<^y=
DBCC SHRINKFILE }!V-FAL
3、压缩数据库 <."KejXg-
dbcc shrinkdatabase(dbname) kO4'|<
4、转移数据库给新用户以已存在用户权限 Y-lTPR<Eq
exec sp_change_users_login 'update_one','newname','oldname' G%viWWTY
go CZog?O}<
5、检查备份集 b*1yvkX5
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' q1Mt5O}
6、修复数据库 m~-O}i~)
ALTER DATABASE [dvbbs] SET SINGLE_USER 1@n'6!]6O
GO B[9y<FB+
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 5&qBG@Hw]
GO K%1`LT5:~
ALTER DATABASE [dvbbs] SET MULTI_USER ehTv@2b
GO D!&]jkUN
7、日志清除 K
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SET NOCOUNT ON /h8100
DECLARE @LogicalFileName sysname, ^0 &jy:{
@MaxMinutes INT, iP6?[pl8
@NewSize INT w@pJ49
USE tablename -- 要操作的数据库名 1)!2D?w
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ik1asj1
@MaxMinutes = 10, -- Limit on time allowed to wrap log. <Yg6=e
@NewSize = 1 -- 你想设定的日志文件的大小(M) VxtX%McK
-- Setup / initialize L8(2or
DECLARE @OriginalSize int TG%w
SELECT @OriginalSize = size |5jrl|
FROM sysfiles ~BMUea(
WHERE name = @LogicalFileName 8.Ufw.
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + AG><5 }
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + t1wzSG
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 5=
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FROM sysfiles w)&?9?~
WHERE name = @LogicalFileName rE]Nr ;Ys
CREATE TABLE DummyTrans pog
(DummyColumn char (8000) not null) E;wT4 T=
DECLARE @Counter INT, ZsSW{ffZ77
@StartTime DATETIME, i|m8#*Hd
@TruncLog VARCHAR(255) 2#/23(Wc
SELECT @StartTime = GETDATE(), *Qyu
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' &4ndi=.#rg
DBCC SHRINKFILE (@LogicalFileName, @NewSize) b[<L
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EXEC (@TruncLog) ]-_ ma
-- Wrap the log if necessary. "z*.Bk
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ?TJ4L/"(k6
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) }QBL{\E!
AND (@OriginalSize * 8 /1024) > @NewSize Xk\IO0GF
BEGIN -- Outer loop. =J|jCK[r
SELECT @Counter = 0 BS(jC
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) \Foo:jON
BEGIN -- update &2S-scP
INSERT DummyTrans VALUES ('Fill Log') k(o(:-+x
DELETE DummyTrans 31UxYBY
SELECT @Counter = @Counter + 1 S|af?IW
END X *EseC
EXEC (@TruncLog) `vz7}TY
END X}Om)WCr
SELECT 'Final Size of ' + db_name() + ' LOG is ' + n.t5:SW
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ;M~9Yr=1
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' Y>atJ
FROM sysfiles #%w+PL:*O
WHERE name = @LogicalFileName maeQ'Sv_&
DROP TABLE DummyTrans oY0*2~sg
SET NOCOUNT OFF A@9\Qd
8、说明:更改某个表 c91^7@Xv
exec sp_changeobjectowner 'tablename','dbo' %|D)U>o{
9、存储更改全部表 Zu2`IzrG#
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch JY@bD:
@OldOwner as NVARCHAR(128), vG7Mk8mIr
@NewOwner as NVARCHAR(128) \Zh&[D!2
AS ay|jq"a
DECLARE @Name as NVARCHAR(128) iJj!-a:z.
DECLARE @Owner as NVARCHAR(128) w}#3 pU<<
DECLARE @OwnerName as NVARCHAR(128) UBJYs{zz
DECLARE curObject CURSOR FOR W?"l6s
select 'Name' = name, ?XP4kjJ
'Owner' = user_name(uid) D+BiclJ
from sysobjects -%|
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d ;
where user_name(uid)=@OldOwner ;Yv{)@'Bc
order by name `wZ
OPEN curObject y5F"JjQAa
FETCH NEXT FROM curObject INTO @Name, @Owner BMI`YGjY1
WHILE(@@FETCH_STATUS=0) `e fiX^
BEGIN %?, 7!|Ls
if @Owner=@OldOwner !#~KSO}zW2
begin ^$}O?y7O
set @OwnerName = @OldOwner + '.' + rtrim(@Name) JZ+6)R
exec sp_changeobjectowner @OwnerName, @NewOwner Vr Lp5?Bh
end zA}JVB
-- select @name,@NewOwner,@OldOwner [VqiF~o,
FETCH NEXT FROM curObject INTO @Name, @Owner Wp+lI1t
END I?E+
close curObject O2?yI8|Jn
deallocate curObject EZ:?
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GO SP/b4
10、SQL SERVER中直接循环写入数据 y10W\beJ
declare @i int m mZP;
set @i=1 h Ypj
while @i<30 {&XTa`C
begin tzfyS#E
insert into test (userid) values(@i) )+|wrK:*v
set @i=@i+1 M$.bC0}T
end S>r}3,]S
小记存储过程中经常用到的本周,本月,本年函数 YtKT3u:x
Dateadd(wk,datediff(wk,0,getdate()),-1) pUS: HJk|
Dateadd(wk,datediff(wk,0,getdate()),6) 7)[2Ud8
Dateadd(mm,datediff(mm,0,getdate()),0) uF1 4;
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) q,<l3r In
Dateadd(yy,datediff(yy,0,getdate()),0) -G@uB_C s
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 6P}?+ Gc
上面的SQL代码只是一个时间段 ~k-'
Dateadd(wk,datediff(wk,0,getdate()),-1) %rJDpB{
Dateadd(wk,datediff(wk,0,getdate()),6) @*~yVV!5
就是表示本周时间段. A,t g268
下面的SQL的条件部分,就是查询时间段在本周范围内的: J[r_ag
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 4H;7GNu
而在存储过程中 GD)paTwO<
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) D
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) $]xH"Z%"