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。 c2 C8g1n
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一、基础 6HWE~`ok6
1、说明:创建数据库 `%"\@<
CREATE DATABASE database-name #r~# I}U
2、说明:删除数据库 `%9 uE(
drop database dbname ShP^A"Do
3、说明:备份sql server u.m[u)HQ
--- 创建 备份数据的 device XnMvKPerv'
USE master ~/iKh11
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 9`X\6s
--- 开始 备份 1FL~ndJs
BACKUP DATABASE pubs TO testBack LxSpctiNx
4、说明:创建新表 ZdWm:(nkU
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ~t~k2^)|"
根据已有的表创建新表: Q1I6$8:7
A:create table tab_new like tab_old (使用旧表创建新表) x}I+Iggi
B:create table tab_new as select col1,col2... from tab_old definition only J$w<$5UY
5、说明:删除新表 C]`$AqKl
drop table tabname qvKG-|j
6、说明:增加一个列 RmeD$>7
Alter table tabname add column col type o&)8o5
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 k1Y ?
7、说明:添加主键: Alter table tabname add primary key(col) 6@F9G4<Z
说明:删除主键: Alter table tabname drop primary key(col) sW'AjI
8、说明:创建索引:create [unique] index idxname on tabname(col....) dhf!o0'1M
删除索引:drop index idxname N gGp
注:索引是不可更改的,想更改必须删除重新建。 `w7v*h|P
9、说明:创建视图:create view viewname as select statement Ma']?Rb`
删除视图:drop view viewname S3*`jF>q
10、说明:几个简单的基本的sql语句 h-K_Lr]
选择:select * from table1 where 范围 a;qryUyG
插入:insert into table1(field1,field2) values(value1,value2) =M[bnq*\
删除:delete from table1 where 范围 lc1(t:"[
更新:update table1 set field1=value1 where 范围 jTtu0Q|
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! .*S#aq4S
排序:select * from table1 order by field1,field2 [desc] b;W3j
总数:select count as totalcount from table1 &4x}ppX
求和:select sum(field1) as sumvalue from table1 0#s"e}@v
平均:select avg(field1) as avgvalue from table1 'ud{m[|
最大:select max(field1) as maxvalue from table1 x$.^"l-vX
最小:select min(field1) as minvalue from table1 L;NvcUFn
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11、说明:几个高级查询运算词 g._]8{K
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A: UNION 运算符 bL+_j}{:N
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。 f<fXsSv(
B: EXCEPT 运算符 }1c|gQ
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。 PI:4m%[
C: INTERSECT 运算符 e L^|v
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。 p6]1w]*R
注:使用运算词的几个查询结果行必须是一致的。 4I
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12、说明:使用外连接 t?-n*9,#S
A、left outer join: BB!THj69a6
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"uu
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 P%:wAYz1^O
B:right outer join: ~"&|W'he[
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。 vkx7paY_
C:full outer join: JHM9
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。 ;!mzyb*
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二、提升 2W96Zju\
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) HV!m8k=6
法一:select * into b from a where 1<>1 JPc+rfF
法二:select top 0 * into b from a $%CF8\0
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ]}-7_n#cC
insert into b(a, b, c) select d,e,f from b; rq/yD,I,
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) r6MMCJ|G
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ;4^Rx
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. \378rQU
4、说明:子查询(表名1:a 表名2:b) 0w\zLU
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) 7Oa#c<2]
5、说明:显示文章、提交人和最后回复时间 Pg0x/X{t
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b mzaWST]
6、说明:外连接查询(表名1:a 表名2:b) vv3*
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 0d"[l@UU0
7、说明:在线视图查询(表名1:a ) &0OG*}gi
select * from (SELECT a,b,c FROM a) T where t.a > 1; a LroD$#
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 mPtZO*Fc
select * from table1 where time between time1 and time2 4$iz4U:P
select a,b,c, from table1 where a not between 数值1 and 数值2 q77;ZPfs8
9、说明:in 的使用方法 8 S:w7Hr
select * from table1 where a [not] in ('值1','值2','值4','值6') &Fzb6/
10、说明:两张关联表,删除主表中已经在副表中没有的信息 B:;pvW]
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) i&Tbz!
11、说明:四表联查问题: uGf@
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 .....
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12、说明:日程安排提前五分钟提醒 3s,g*
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 7a=gH2]&
13、说明:一条sql 语句搞定数据库分页 */)c?)"
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 DnMwUykF>0
14、说明:前10条记录 av}k)ZT_
select top 10 * form table1 where 范围 eueH)Xkf
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.) G7`ko1-
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) \Xt7`I<
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 !N\@'F!
(select a from tableA ) except (select a from tableB) except (select a from tableC) '8RsN-w
17、说明:随机取出10条数据 Bw)/DM]
select top 10 * from tablename order by newid() F#,90F'
18、说明:随机选择记录 2\A$6N;_
select newid() UUYSFa%
19、说明:删除重复记录 dh`K`b4I
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) =w_Ype`
20、说明:列出数据库里所有的表名 xaq-.IQAM$
select name from sysobjects where type='U' t9k zw*U9
21、说明:列出表里的所有的 N_kMK
select name from syscolumns where id=object_id('TableName') |C;=-|
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。 Z58X5"
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 (Ft+uuG
显示结果: ~ drS} V
type vender pcs zH?!
电脑 A 1 VuhGx:Xl
电脑 A 1 *KZYv=s,u
光盘 B 2 4C6YO
光盘 A 2 6"LcJ%o
手机 B 3 U2tV4_ e
手机 C 3 &Cq`Y !y
23、说明:初始化表table1 75cW_t,g
TRUNCATE TABLE table1 )0.kv2o.
24、说明:选择从10到15的记录 T6y\|
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 8O5s`qKMYT
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三、技巧 %B2'~|g
1、1=1,1=2的使用,在SQL语句组合时用的较多 ~RW+GTe
"where 1=1" 是表示选择全部 "where 1=2"全部不选, |B?m,U$A!
如: AP n| \
if @strWhere !='' h0*!;Z7
begin u:6Ic)7'
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere v+W&9>
end )al]*[lY
else %~O,zs.2p
begin er("wtM
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' .KB^3pOpx
end &n}]w+w
我们可以直接写成 X[-xowE-
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere YFLZ %(
2、收缩数据库 s[RAHU
--重建索引 dc+>m,3$
DBCC REINDEX |IeTqEu9
DBCC INDEXDEFRAG 7Kr*P<-G
--收缩数据和日志 {g'(~ qv
DBCC SHRINKDB <prk8jSWV
DBCC SHRINKFILE OZb-:!m*
3、压缩数据库 FZ{h?#2?
dbcc shrinkdatabase(dbname) [SjqOTon{
4、转移数据库给新用户以已存在用户权限 jnkR}wAA
exec sp_change_users_login 'update_one','newname','oldname' !hA-_
go h"[AOfTE$
5、检查备份集 MD}w Y><C
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' f&NgS+<K$
6、修复数据库 =J]&c?I
ALTER DATABASE [dvbbs] SET SINGLE_USER ,Q3T
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GO .Yamc#A-
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK m<<+
GO ]g#: KAqz
ALTER DATABASE [dvbbs] SET MULTI_USER G*?8MTP8![
GO a(m2n.0'>
7、日志清除 e[{0)y>=
SET NOCOUNT ON uP`Z12&
DECLARE @LogicalFileName sysname, v^sv<4*%
@MaxMinutes INT, paA(C|%{
@NewSize INT +C^nO=[E
USE tablename -- 要操作的数据库名 6iry6wcHm
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Hc;[Cs0
@MaxMinutes = 10, -- Limit on time allowed to wrap log. f$o_e90mu
@NewSize = 1 -- 你想设定的日志文件的大小(M) vz@A;t
-- Setup / initialize {UX!go^J
DECLARE @OriginalSize int Fx] WCQo
SELECT @OriginalSize = size #>a\>iKQ2q
FROM sysfiles S^JbyD_yoh
WHERE name = @LogicalFileName 6gU96Z
SELECT 'Original Size of ' + db_name() + ' LOG is ' + <.%4 !
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + SJlr53
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' rP'me2
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FROM sysfiles /`Ug9,*
WHERE name = @LogicalFileName ]
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CREATE TABLE DummyTrans D5gFXEeh
(DummyColumn char (8000) not null) s-NX o
DECLARE @Counter INT, eFB5=)ld
@StartTime DATETIME, ` _6C{<O
@TruncLog VARCHAR(255) H-!,yte
SELECT @StartTime = GETDATE(), K6)Gc%:`
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' vRTkgH#4l
DBCC SHRINKFILE (@LogicalFileName, @NewSize) v1#otrf
EXEC (@TruncLog) N_LM/of|D
-- Wrap the log if necessary. WSPI|#Xr%
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 8$]1M,$r
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) n.}Zk G0`
AND (@OriginalSize * 8 /1024) > @NewSize xf'V{9*
BEGIN -- Outer loop. "-E\[@/
SELECT @Counter = 0 "6("9"
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ;_XFo&@
BEGIN -- update K,tQ!kk
INSERT DummyTrans VALUES ('Fill Log') PioZIb/{
DELETE DummyTrans %6t:(z
SELECT @Counter = @Counter + 1 ./XYd"p
END Qry@
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EXEC (@TruncLog) JB\UKZXw
END !@5 9)
SELECT 'Final Size of ' + db_name() + ' LOG is ' + `](e:be}
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + NYhB'C2
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ~kV/!=
FROM sysfiles Mg+2.
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WHERE name = @LogicalFileName d.aS{;pse
DROP TABLE DummyTrans \wmN
SET NOCOUNT OFF .w:DFk^E]b
8、说明:更改某个表 PgAf\.48a
exec sp_changeobjectowner 'tablename','dbo' XjB W9a
9、存储更改全部表 05|=`eJ
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch TbMW|0 #w
@OldOwner as NVARCHAR(128), \a<wKTkn
@NewOwner as NVARCHAR(128) a1+oj7
AS |o7[|3:M
DECLARE @Name as NVARCHAR(128) xKbXt;l2
DECLARE @Owner as NVARCHAR(128) SA:Zc^aV
DECLARE @OwnerName as NVARCHAR(128) r[e##M
DECLARE curObject CURSOR FOR (xycJ`N
select 'Name' = name, ?C]vS_jAh
'Owner' = user_name(uid) ??5Q)Erm1
from sysobjects pG_;$8Hc
where user_name(uid)=@OldOwner z xEL+ P
order by name 7o\@>rNWP
OPEN curObject y4yhF8E>;U
FETCH NEXT FROM curObject INTO @Name, @Owner @ 8(q$
WHILE(@@FETCH_STATUS=0) A]*}HZ,
BEGIN +tB=OwU%0
if @Owner=@OldOwner ]IaMp788
begin SV4E0c>
set @OwnerName = @OldOwner + '.' + rtrim(@Name) C-xr"]#]
exec sp_changeobjectowner @OwnerName, @NewOwner v{RZJ^1
end aNsBcov3O
-- select @name,@NewOwner,@OldOwner W@>% {eE
FETCH NEXT FROM curObject INTO @Name, @Owner gE-tjoJ
END eNh39er
close curObject ^+ml5m
deallocate curObject t6rRU~;}
GO cs48*+m
10、SQL SERVER中直接循环写入数据 _r#Z}HK
declare @i int ZT*ydln
set @i=1 *YI98
while @i<30 yHYsZ,GE
begin #Bze,?@
insert into test (userid) values(@i) I]|Pq
set @i=@i+1 oE@a'*.\
end &md`$a/
小记存储过程中经常用到的本周,本月,本年函数 OHN _
Dateadd(wk,datediff(wk,0,getdate()),-1) RIR\']WN
Dateadd(wk,datediff(wk,0,getdate()),6) A.F%Ycq
Dateadd(mm,datediff(mm,0,getdate()),0)
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ?Rb9|`6
Dateadd(yy,datediff(yy,0,getdate()),0) P.se'z)E
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) W<{h,j8
上面的SQL代码只是一个时间段 |o"?gB}Dh
Dateadd(wk,datediff(wk,0,getdate()),-1) LG0;#3YwH
Dateadd(wk,datediff(wk,0,getdate()),6) h#I>M`|
就是表示本周时间段. $V;i
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下面的SQL的条件部分,就是查询时间段在本周范围内的: 4IK( 7
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) fy1|$d{'
而在存储过程中 Mc
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select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) W_293["lS
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) S)(.,x