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。 lu_kir~
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一、基础 a+HGlj 2>
1、说明:创建数据库 [Rj_p&'
CREATE DATABASE database-name ^sF/-/ {?U
2、说明:删除数据库 iXoEdt)
drop database dbname yH=Hrz:<eM
3、说明:备份sql server q8m{zSr
--- 创建 备份数据的 device WGmXq.
USE master gGaA;YW1
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 8v<802
--- 开始 备份 )WBp.j /#
BACKUP DATABASE pubs TO testBack c)*,">$#
4、说明:创建新表 {[|je]3v
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) g~7x+cu0
根据已有的表创建新表: Arr(rM
A:create table tab_new like tab_old (使用旧表创建新表) T!f+H?6
B:create table tab_new as select col1,col2... from tab_old definition only VyMFALSe]h
5、说明:删除新表 ?l> <?i
drop table tabname D(;jv= "/
6、说明:增加一个列 X-,mNvz
Alter table tabname add column col type \m xi8Z
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注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。
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7、说明:添加主键: Alter table tabname add primary key(col) {"dvU"y)\
说明:删除主键: Alter table tabname drop primary key(col) B*OEG*t
8、说明:创建索引:create [unique] index idxname on tabname(col....) lXT+OJF
删除索引:drop index idxname >z'T"R/
注:索引是不可更改的,想更改必须删除重新建。 yG'
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9、说明:创建视图:create view viewname as select statement <`Xt?K
删除视图:drop view viewname ^P!(*k#T
10、说明:几个简单的基本的sql语句 +6~y1s/B[
选择:select * from table1 where 范围 ;s$,}O.
插入:insert into table1(field1,field2) values(value1,value2) 9ZD>_a
删除:delete from table1 where 范围 (DIMt-wz
更新:update table1 set field1=value1 where 范围 whW%c8
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ts:YJAu+F
排序:select * from table1 order by field1,field2 [desc] Y5ZBP?P
总数:select count as totalcount from table1 3wYhDxY1
求和:select sum(field1) as sumvalue from table1 Qi= pP/Y
平均:select avg(field1) as avgvalue from table1 !g.?+~@
最大:select max(field1) as maxvalue from table1 Q4Zw<IZv5
最小:select min(field1) as minvalue from table1 H2jF=U"=
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11、说明:几个高级查询运算词 /;X+<Wj
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A: UNION 运算符 A{ a4;`}5
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。 .)g7s? K
B: EXCEPT 运算符 ?3_^SRW&a
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。 T5_/*`F
C: INTERSECT 运算符 mgd)wZNV
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。 Z1~`S!(}
注:使用运算词的几个查询结果行必须是一致的。 _'mK=`>u
12、说明:使用外连接 EXbaijHQG
A、left outer join: R:5uZAx
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。 1F'x$~ZI
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c q/h, jM
B:right outer join: s~NJy'Y
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 ?mp}_x#=
C:full outer join: :|HCUZ*H(T
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 )p`zN=t
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二、提升 jmBsPSGIC
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ,$+ P
法一:select * into b from a where 1<>1 &SW~4 {n:
法二:select top 0 * into b from a PJ))p6
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用)
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insert into b(a, b, c) select d,e,f from b; v.6K;TY.
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) 3Viz0I<%
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 rqWD#FB=z
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. e9;5.m
4、说明:子查询(表名1:a 表名2:b) >c@jl
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) Tr.u'b(
5、说明:显示文章、提交人和最后回复时间 mhgvN-? "h
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b M,vCAZ
6、说明:外连接查询(表名1:a 表名2:b) ZK4d;oa",
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c (:>Sh0.
7、说明:在线视图查询(表名1:a ) B%I<6E[D
select * from (SELECT a,b,c FROM a) T where t.a > 1; z7s}-w,
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 veAdk9
select * from table1 where time between time1 and time2 E h+m|A
select a,b,c, from table1 where a not between 数值1 and 数值2 Ly-}HW (
9、说明:in 的使用方法 AIG5a$}&
select * from table1 where a [not] in ('值1','值2','值4','值6') gX~lYdA
10、说明:两张关联表,删除主表中已经在副表中没有的信息 qQwf#&
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) }vEMG-sxX
11、说明:四表联查问题: FL[,?RU?2
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... >aAsUL5W
12、说明:日程安排提前五分钟提醒 tx$`1KA
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 b?j\YX[e
13、说明:一条sql 语句搞定数据库分页 P]0/ S
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 |Sv}/P-
14、说明:前10条记录 `hDH7u!U.
select top 10 * form table1 where 范围 HE:]zH
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.) (&1565
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 6(/*E=bOKV
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 ID~}pEQ
(select a from tableA ) except (select a from tableB) except (select a from tableC) fD*jzj7o,
17、说明:随机取出10条数据 &S=xSs:q.
select top 10 * from tablename order by newid() gn:&akg
18、说明:随机选择记录 P>hR${KE
select newid() J%IKdxa
19、说明:删除重复记录 owzcc-g
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) R9-Uoc/
20、说明:列出数据库里所有的表名 }_oQg_-7e
select name from sysobjects where type='U' 5i-VnG
21、说明:列出表里的所有的 IOY<'t+
select name from syscolumns where id=object_id('TableName') ig ^x%!;
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 ! JauMR
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type Zg3
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显示结果: eWr2UXv$
type vender pcs hO2W!68
电脑 A 1 X`A+/{ H
电脑 A 1 7;a
光盘 B 2 ^g=j`f[T
光盘 A 2 6eQa@[.Q
手机 B 3 >W6?!ue_
手机 C 3 r8>Qs RnU%
23、说明:初始化表table1 fuT Bh6w&
TRUNCATE TABLE table1 -
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24、说明:选择从10到15的记录 /<k]mY cu
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc m>f8RBp]'
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三、技巧 FK@Gd)(
1、1=1,1=2的使用,在SQL语句组合时用的较多 1 fTf+P
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ;NF:98
如: ZU;nXqjc
if @strWhere !='' tu^C<MV
begin G5NAwpZf
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Ry40:;MYN
end $lg{J$
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else A}[x))r
begin y\=^pla
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' s)#TT9BbV
end U
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我们可以直接写成 <=!FB8 .
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere "%w E>E
2、收缩数据库 U^kk0OT^
--重建索引 EUbyQL
DBCC REINDEX Bo;{ QoB
DBCC INDEXDEFRAG
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--收缩数据和日志 \F14]`i
DBCC SHRINKDB -d[Gy-
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DBCC SHRINKFILE 13A~."b
3、压缩数据库 jd.w7.8
dbcc shrinkdatabase(dbname) X2`n&JE
4、转移数据库给新用户以已存在用户权限 x b!&'cw
exec sp_change_users_login 'update_one','newname','oldname' s=Xg6 D
go [&)*jc16
5、检查备份集 @+sYwlA~
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' BD [<>Wm
6、修复数据库 ;P^}2i[q>[
ALTER DATABASE [dvbbs] SET SINGLE_USER 0*]ZC'pm
GO }"STc&1
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Qx8O&C?Ti
GO }[y_Fr0
ALTER DATABASE [dvbbs] SET MULTI_USER l)f 2T@bHl
GO T2 TWb
7、日志清除 jxZ_-1
SET NOCOUNT ON |=[._VH1
DECLARE @LogicalFileName sysname, @xr}(.
@MaxMinutes INT, jP.dQj^j&
@NewSize INT =3=8oF x8
USE tablename -- 要操作的数据库名 C_&ZQlgQ
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 tlgg~MViS
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ^*F'[!. p
@NewSize = 1 -- 你想设定的日志文件的大小(M) 71Y3.1+
-- Setup / initialize _
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DECLARE @OriginalSize int U.1&'U*
SELECT @OriginalSize = size v!#koqd1y.
FROM sysfiles _$yS4= .
WHERE name = @LogicalFileName bp'\nso/
SELECT 'Original Size of ' + db_name() + ' LOG is ' + |`d-;pk!%
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' +
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' M
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FROM sysfiles @=K*gbq5
WHERE name = @LogicalFileName 2+yti,s+/
CREATE TABLE DummyTrans :Aj[#4-=
(DummyColumn char (8000) not null) +A1xqOB
DECLARE @Counter INT, !.7m4mKzo
@StartTime DATETIME, NYeL1h)l
@TruncLog VARCHAR(255) dvLL~VP
SELECT @StartTime = GETDATE(), 2^)_XVX1
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' -kb;h F}.
DBCC SHRINKFILE (@LogicalFileName, @NewSize) rnC<(f22
EXEC (@TruncLog) ]'<"qY
-- Wrap the log if necessary. EME}G42KN
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired d~y]7h |
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 26MoYO!k
AND (@OriginalSize * 8 /1024) > @NewSize UPkc-^BN
BEGIN -- Outer loop. |21*p#>
SELECT @Counter = 0 W(EN01d \
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ,vB nr_D#
BEGIN -- update :M.]- +(
INSERT DummyTrans VALUES ('Fill Log') B3p79j
DELETE DummyTrans GmZ2a-M
SELECT @Counter = @Counter + 1 JykN EMB#
END %1rN6A!%
EXEC (@TruncLog) ,qIut|C*
END )Ut9k
SELECT 'Final Size of ' + db_name() + ' LOG is ' + .#LHj}u
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + A",R2d
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' Ci?RuZ"
FROM sysfiles " t,ZO
WHERE name = @LogicalFileName ,D' bIk
DROP TABLE DummyTrans fz%e?@>q
SET NOCOUNT OFF 9
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8、说明:更改某个表 '\P+Bu]6&
exec sp_changeobjectowner 'tablename','dbo' [6%y RQ_
9、存储更改全部表 }ok'd=M
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch [jTZxH<
@OldOwner as NVARCHAR(128), )Mh5q&ow
@NewOwner as NVARCHAR(128) k;HI-v
AS Is!+`[ma
DECLARE @Name as NVARCHAR(128) >1q:-^
DECLARE @Owner as NVARCHAR(128) ckbD/+
DECLARE @OwnerName as NVARCHAR(128) 6>[J^k%~w)
DECLARE curObject CURSOR FOR CIQ9dx7>
select 'Name' = name, \cQ+9e)
'Owner' = user_name(uid) bLO^5` 6
from sysobjects 3A3WD+[L
where user_name(uid)=@OldOwner ygxaT"3"=
order by name RggO|s+0;
OPEN curObject Fyc":{Jd
FETCH NEXT FROM curObject INTO @Name, @Owner A s8IjGNs{
WHILE(@@FETCH_STATUS=0) <q=]n%nX
BEGIN v>5TTL~?
if @Owner=@OldOwner d6A+pa'2
begin 72dd%
set @OwnerName = @OldOwner + '.' + rtrim(@Name) *enT2Q
exec sp_changeobjectowner @OwnerName, @NewOwner
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end @e+qe9A|
-- select @name,@NewOwner,@OldOwner 8|Wl|@1(
FETCH NEXT FROM curObject INTO @Name, @Owner nr%P11U\c
END c22L]Sxo
close curObject FB
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deallocate curObject wdRk+
GO pZ 7KWk4
10、SQL SERVER中直接循环写入数据 |^O3~!JP(>
declare @i int hn e}G._b
set @i=1 JR|P]}
while @i<30 l>pnY%(A
begin M aP -
insert into test (userid) values(@i) 4TcW%
set @i=@i+1 p%5(Qqmlk
end p+Fh9N<F9
小记存储过程中经常用到的本周,本月,本年函数 rrl{3
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Dateadd(wk,datediff(wk,0,getdate()),-1) 9)'wgI#
Dateadd(wk,datediff(wk,0,getdate()),6) H4BuxM_r
Dateadd(mm,datediff(mm,0,getdate()),0) +[#^c3x2
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) fAD
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Dateadd(yy,datediff(yy,0,getdate()),0) XW*d\vDun
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) sX(rJLbD
上面的SQL代码只是一个时间段 *!,k`=.([#
Dateadd(wk,datediff(wk,0,getdate()),-1) P]4@|u;=6[
Dateadd(wk,datediff(wk,0,getdate()),6)
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就是表示本周时间段. !uhh_3RH
下面的SQL的条件部分,就是查询时间段在本周范围内的: &izk$~
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) p9eTrFDy?
而在存储过程中 nu6v@<<F>
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) [-1Yyy1}
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) /re0"!0y