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。 %rTXT
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一、基础 zu}h3n5
1、说明:创建数据库 %&^F.JTt\
CREATE DATABASE database-name N
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2、说明:删除数据库 7;n'4LIa9
drop database dbname .J~iRhVOF
3、说明:备份sql server ZBJYpeGe
--- 创建 备份数据的 device b=QO ^
USE master =? x A*_^
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' T.HI
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--- 开始 备份 nrA}36 E
BACKUP DATABASE pubs TO testBack ;G~0 VM2|
4、说明:创建新表 %.b)%=
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) LIVVb"V|,
根据已有的表创建新表: P!m~tu}B
A:create table tab_new like tab_old (使用旧表创建新表) @-;-DB]j
B:create table tab_new as select col1,col2... from tab_old definition only Xig+[2zS
5、说明:删除新表 7BF't!-2F
drop table tabname ^$_a_ft#
6、说明:增加一个列 e9q/[xMi
Alter table tabname add column col type iYv6B6o/99
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 P7E}^y`e
7、说明:添加主键: Alter table tabname add primary key(col) [(`T*c.#.X
说明:删除主键: Alter table tabname drop primary key(col) d?&?$qf[
8、说明:创建索引:create [unique] index idxname on tabname(col....) q!<`ci,uS
删除索引:drop index idxname R6)p4#|i
注:索引是不可更改的,想更改必须删除重新建。 $RKd@5XP
9、说明:创建视图:create view viewname as select statement c?eV8h1G
删除视图:drop view viewname \GbT^!dj
10、说明:几个简单的基本的sql语句 m{x!uq
选择:select * from table1 where 范围 uwWfL32
插入:insert into table1(field1,field2) values(value1,value2) .Kq>/6
删除:delete from table1 where 范围 (XRj##G{
更新:update table1 set field1=value1 where 范围 T |'Ur#
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! dp2".
排序:select * from table1 order by field1,field2 [desc] bK("8T\?
总数:select count as totalcount from table1 S53 [Ja
求和:select sum(field1) as sumvalue from table1 _>A])B
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平均:select avg(field1) as avgvalue from table1 }k<b)I*A
最大:select max(field1) as maxvalue from table1 A@_F ;4X
最小:select min(field1) as minvalue from table1 "`,PLC
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11、说明:几个高级查询运算词 T[<llh'+
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A: UNION 运算符 QD<^VY6
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。 !V@Y \M
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B: EXCEPT 运算符 v<tH 3I+
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。 \9i.dF
C: INTERSECT 运算符 klUxt?-
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。 !U,qr0h
注:使用运算词的几个查询结果行必须是一致的。 0tn5>Dsk
12、说明:使用外连接 n4k.tq
A、left outer join: 8o4<F%ot
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!`.y7hY@
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 g=b[V
B:right outer join: $|6Le;
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右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 cdP+X'Y4D
C:full outer join: ))G%C6-
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 u;&`_=p
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二、提升 \D, 0
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ,`/!0Wmt
法一:select * into b from a where 1<>1 ui G7
法二:select top 0 * into b from a Fdu0?H2TL
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) J%f5NSSU{6
insert into b(a, b, c) select d,e,f from b; _ZzPy;[i?
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) m]N4.J
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 2;[75(l6|}
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. >|@ /GpD
4、说明:子查询(表名1:a 表名2:b) f5wOk&G
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) 1uMnlimr
5、说明:显示文章、提交人和最后回复时间 >V87#E
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b -&))$h3o\
6、说明:外连接查询(表名1:a 表名2:b) >S5D-)VX
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c YV{^S6M
7、说明:在线视图查询(表名1:a ) p5)A"p8"9,
select * from (SELECT a,b,c FROM a) T where t.a > 1; wm*`
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 =#T6,[5
select * from table1 where time between time1 and time2 "@GopD
select a,b,c, from table1 where a not between 数值1 and 数值2 ^o:0 Y}v=
9、说明:in 的使用方法 *M+:GH/5
select * from table1 where a [not] in ('值1','值2','值4','值6') 8xg:ItJaA0
10、说明:两张关联表,删除主表中已经在副表中没有的信息 )5d&K8@
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) +*)B;)P
11、说明:四表联查问题: (sJ{27b_
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 ..... _rs!6tp
12、说明:日程安排提前五分钟提醒 A_Sl#e
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 9<[RXY
13、说明:一条sql 语句搞定数据库分页 O%(:8nIgZ
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 RJF1~9
14、说明:前10条记录 u33+ ikYv
select top 10 * form table1 where 范围 &}:Hp9n
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.) ,!%[CpM3
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) $3Wl~
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16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 a/L?R
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(select a from tableA ) except (select a from tableB) except (select a from tableC) ?h
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17、说明:随机取出10条数据 \^N9Q9{7]
select top 10 * from tablename order by newid()
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18、说明:随机选择记录 j*W]^uT,
select newid() 5>}L3r>a;
19、说明:删除重复记录 {U^mL6=&v
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) <diI*H<G
20、说明:列出数据库里所有的表名 1#]tCi`
select name from sysobjects where type='U' y7d)[d*Mz
21、说明:列出表里的所有的 4y
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select name from syscolumns where id=object_id('TableName') dHf_&X2A
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 rS(693kb
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type nF
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显示结果: 4X#>;
type vender pcs ?$-OdABXHK
电脑 A 1 4vBZb^W;9
电脑 A 1 Z9=Cw0( w?
光盘 B 2 w{2V7*+l
光盘 A 2 e
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手机 B 3 ",&}vfD4M
手机 C 3 _a15R/S
23、说明:初始化表table1 YDjQ&EH
TRUNCATE TABLE table1 m>zUwGYEu
24、说明:选择从10到15的记录 us`hR!_
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc JguE#ob2
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三、技巧 `'Z ;+h]
1、1=1,1=2的使用,在SQL语句组合时用的较多 ;EL!TzL:8
"where 1=1" 是表示选择全部 "where 1=2"全部不选, rU.ew~
如: Sm+Ek@Ax
if @strWhere !='' lmr{Ib2a
begin
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Am kHVg
end 86IAAO`#
else eSa ]6
begin xiA9X]FB
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' *RxbqB-
end G_j`6v)
我们可以直接写成 8.Y6r
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ^U~YG=!ww
2、收缩数据库 LsV!Sd
--重建索引 KkAk(9Q/3
DBCC REINDEX l<7 b
DBCC INDEXDEFRAG X5>p~;[9
--收缩数据和日志 N^mY/`2
DBCC SHRINKDB &~$^a1D6
DBCC SHRINKFILE er l_Gg
3、压缩数据库 f*oL8"?u&
dbcc shrinkdatabase(dbname) P-^Z7^o-bX
4、转移数据库给新用户以已存在用户权限 \zj8| +
exec sp_change_users_login 'update_one','newname','oldname' 2&$ A x
go qMI%=@=
5、检查备份集 !^l<jrM
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' g%4|vA8
6、修复数据库 z${B|
ALTER DATABASE [dvbbs] SET SINGLE_USER .]v8W51Y
GO lpSM p
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK <FGNV+?%e
GO +Icg;m{
ALTER DATABASE [dvbbs] SET MULTI_USER \8_&@uLm
GO L2Gm0 v
7、日志清除 *<Qn)Az
SET NOCOUNT ON =H!u4
DECLARE @LogicalFileName sysname, LAMTf"a
@MaxMinutes INT, m{R`1cN=Hg
@NewSize INT s'} oVx]
USE tablename -- 要操作的数据库名 mKxQU0 `
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 17<\Q(YQ=
@MaxMinutes = 10, -- Limit on time allowed to wrap log. -fG;`N5U
@NewSize = 1 -- 你想设定的日志文件的大小(M) U&`M G1uHe
-- Setup / initialize lg1?g)lv
DECLARE @OriginalSize int (F$q|qZ%
SELECT @OriginalSize = size gfih;i.pY
FROM sysfiles AO8`ItNZdT
WHERE name = @LogicalFileName #MOEY|6
SELECT 'Original Size of ' + db_name() + ' LOG is ' + #1V vK
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + <5C3c&sds
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 4\Q ?4ZX
FROM sysfiles ']}ZI 8
WHERE name = @LogicalFileName Bz7T1B&to
CREATE TABLE DummyTrans $+7MY-9T
(DummyColumn char (8000) not null) 'H*S-d6V
DECLARE @Counter INT, 6AZ/whn#
@StartTime DATETIME, 3(AgUq
@TruncLog VARCHAR(255) bX5>qqB]
SELECT @StartTime = GETDATE(), 1{nXmtvr
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' )ALf!E%{
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 8Jxo;Y
EXEC (@TruncLog) 'y;[
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-- Wrap the log if necessary. /o8h1L=
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 7c+TS--
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) &IOChQ`8P
AND (@OriginalSize * 8 /1024) > @NewSize a7OD%yQ
BEGIN -- Outer loop. 3}LTEsdM
SELECT @Counter = 0 #Q$9Eq8"[
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) a{Tv#P*!
BEGIN -- update 1_GUi
INSERT DummyTrans VALUES ('Fill Log') MlS<txFPS
DELETE DummyTrans ?L{[84GSO
SELECT @Counter = @Counter + 1 hQ8/-#LO_
END f5d"H6%L
EXEC (@TruncLog) P) GBuW
END \t^q@}~0Wz
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ]hv4EL(zi
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + kQ{pFFO
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ,}`II|.oB
FROM sysfiles
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WHERE name = @LogicalFileName .xCO_7Rd
DROP TABLE DummyTrans 3VALrb;
SET NOCOUNT OFF "'II~/9
8、说明:更改某个表 \f@PEiARG7
exec sp_changeobjectowner 'tablename','dbo' -i?!em'J
9、存储更改全部表 SaQ_%-p
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch oACuI|b
@OldOwner as NVARCHAR(128), JBi<TDm/
@NewOwner as NVARCHAR(128) ,$W7Q
AS b_\aSEaTT
DECLARE @Name as NVARCHAR(128) (j}"1
DECLARE @Owner as NVARCHAR(128) Ou8@7S
DECLARE @OwnerName as NVARCHAR(128) 0I~xD9l9
DECLARE curObject CURSOR FOR x:@Ht TX
select 'Name' = name, yv4hH4Io
'Owner' = user_name(uid) ldi'@^
from sysobjects y=5s~7]
where user_name(uid)=@OldOwner R}>Gk
order by name BE}lzn=sF
OPEN curObject N7}.9%EV
FETCH NEXT FROM curObject INTO @Name, @Owner N<Ti[Q]G
WHILE(@@FETCH_STATUS=0) !t~S.`vF
BEGIN tY%c-m
if @Owner=@OldOwner zOWbdd_zl
begin f:Ju20D
set @OwnerName = @OldOwner + '.' + rtrim(@Name) @x"vGYKd
exec sp_changeobjectowner @OwnerName, @NewOwner [S-NGip
end rv:,Os_
-- select @name,@NewOwner,@OldOwner c?>Q!sC
FETCH NEXT FROM curObject INTO @Name, @Owner vL\wA_z"<H
END XSn^$$S
close curObject rK}*Uwut
deallocate curObject q.uIZ
GO q;t
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10、SQL SERVER中直接循环写入数据 ?<xGO@b
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declare @i int L;E9"7Jo
set @i=1 QZt/Rm>W0
while @i<30 2/qfK+a
begin ]}~*uT}>
insert into test (userid) values(@i) )k <ON~x
set @i=@i+1 O' A''}M
end 3DMfR
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小记存储过程中经常用到的本周,本月,本年函数 )bw^!w)
Dateadd(wk,datediff(wk,0,getdate()),-1) C03ehjT<
Dateadd(wk,datediff(wk,0,getdate()),6) tezsoR!.ak
Dateadd(mm,datediff(mm,0,getdate()),0) u{tjB/K&
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) JU/K\S2%,
Dateadd(yy,datediff(yy,0,getdate()),0) B5zu?AG
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) SYeCz(H>d
上面的SQL代码只是一个时间段 e=1&mO?
Dateadd(wk,datediff(wk,0,getdate()),-1) }4
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Dateadd(wk,datediff(wk,0,getdate()),6) 9V[|_
就是表示本周时间段. @H1pPr
下面的SQL的条件部分,就是查询时间段在本周范围内的: a?M<r>
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) I zM =?,`
而在存储过程中 G@
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select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) E;| q
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) L8/o9N1