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。 txFcV
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一、基础 TFYp=xK(
1、说明:创建数据库 sL4+O P-
CREATE DATABASE database-name flS_rY5
2、说明:删除数据库 $LHF=tYS
drop database dbname 7i0;Ss*
3、说明:备份sql server Gi Max
--- 创建 备份数据的 device ,nGZ(EBD
USE master +x)x&;B)/
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' h{.x:pPXy
--- 开始 备份 .&;:X )
BACKUP DATABASE pubs TO testBack GN=-dLN
4、说明:创建新表 1(vcM
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) iL;{]A'0
根据已有的表创建新表: t`G<}t
A:create table tab_new like tab_old (使用旧表创建新表) sHm:G_
B:create table tab_new as select col1,col2... from tab_old definition only CW'<Nh
5、说明:删除新表 6r }w
drop table tabname B/gI~e0
6、说明:增加一个列 :r+F95e
Alter table tabname add column col type J 7]LMw7
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 K?gO]T{6
7、说明:添加主键: Alter table tabname add primary key(col) #|;;>YnZ
说明:删除主键: Alter table tabname drop primary key(col) y2:Bv2}
8、说明:创建索引:create [unique] index idxname on tabname(col....) Igb%bO_
删除索引:drop index idxname ^^kL.C Ym
注:索引是不可更改的,想更改必须删除重新建。 Dy^A??A[E}
9、说明:创建视图:create view viewname as select statement U{ZKxE
删除视图:drop view viewname }ZkGH}K_}
10、说明:几个简单的基本的sql语句 {9|S,<9
选择:select * from table1 where 范围 o>MB8[r
插入:insert into table1(field1,field2) values(value1,value2) /[=U$=uH
删除:delete from table1 where 范围 m?]=
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更新:update table1 set field1=value1 where 范围 '=1@,Skj-
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! y7-daek
排序:select * from table1 order by field1,field2 [desc] OJ,Z
总数:select count as totalcount from table1 &O|qx~(
求和:select sum(field1) as sumvalue from table1 ~NBlJULS
平均:select avg(field1) as avgvalue from table1 7da~+(yhr
最大:select max(field1) as maxvalue from table1 }-%:!*bLj
最小:select min(field1) as minvalue from table1 i?IV"*Ob1N
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11、说明:几个高级查询运算词 ]Ag{#GJ5D
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A: UNION 运算符 +9]CGYj
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。 /A>1TPb09"
B: EXCEPT 运算符 A1/[3Bz
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。 z.0!FUd
C: INTERSECT 运算符 *%jd>e7d
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。 *FC26_pH
注:使用运算词的几个查询结果行必须是一致的。 EQ2HQz]
12、说明:使用外连接 %)PQomn?
A、left outer join: O^<\]_l
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。
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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 cPg$*,]
B:right outer join: H;Cv]-
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。 k*o>ZpjNH
C:full outer join: 2br~Vn0N
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。 Ahrtl6@AS
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二、提升 *>J45U(6:
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) "<1-9CMl
法一:select * into b from a where 1<>1 Vo(V<2lw}
法二:select top 0 * into b from a _NB8>v
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 28=L9q
insert into b(a, b, c) select d,e,f from b; $[g8j`or!
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) <: I]0|[
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 &8@
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例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ;1L7+.A
4、说明:子查询(表名1:a 表名2:b) N3o
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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) {14sI*b16
5、说明:显示文章、提交人和最后回复时间 CV7%ud]E
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b A\T9>z^k
6、说明:外连接查询(表名1:a 表名2:b) u\P)x~-TM
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ;%Rp=&J
7、说明:在线视图查询(表名1:a ) V(<(k,8=
select * from (SELECT a,b,c FROM a) T where t.a > 1; .tt= \R
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 Su/}OS\R
select * from table1 where time between time1 and time2 CpdQ]Ai[
select a,b,c, from table1 where a not between 数值1 and 数值2
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9、说明:in 的使用方法 ZA8FX
select * from table1 where a [not] in ('值1','值2','值4','值6') GL8 N!,
10、说明:两张关联表,删除主表中已经在副表中没有的信息 B6"pw0
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) )`-vN^1S-
11、说明:四表联查问题: p^i]{"sjbU
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 ..... *kKdL
12、说明:日程安排提前五分钟提醒 LAPCL&Z
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 XYHVw)
13、说明:一条sql 语句搞定数据库分页 *&vi3#ur
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 V|G[j\]E<
14、说明:前10条记录 6uubkt
select top 10 * form table1 where 范围 gfmaO]
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.) XaR(~2
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) g@IYD
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 9}Qrb@DT
(select a from tableA ) except (select a from tableB) except (select a from tableC) 7kH
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17、说明:随机取出10条数据 IXt cHAgX
select top 10 * from tablename order by newid() UCS`09KNJ
18、说明:随机选择记录 =%R|@lz_x
select newid() f f_| 3G
19、说明:删除重复记录 kH>^3(Q\
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) +d/^0^(D\5
20、说明:列出数据库里所有的表名 MD=VR(P?eq
select name from sysobjects where type='U' kG|pM54:^
21、说明:列出表里的所有的 oLz9mqp2%
select name from syscolumns where id=object_id('TableName') Y~uqKb;A
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。 v9+1[Y";
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 ~7"6Y]
显示结果: ~#V1Gunq
type vender pcs ts~$'^K[-
电脑 A 1 iMXK_O%
电脑 A 1 SM8m\c
光盘 B 2 IX
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光盘 A 2 qD/FxR-!
手机 B 3 X]AbBzy
手机 C 3 qr[+^*Ha
23、说明:初始化表table1 DU.[Sp
TRUNCATE TABLE table1 4Q
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24、说明:选择从10到15的记录 %QKRl5RM-
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc "f3KE=cUm
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三、技巧 i=8){GX4
1、1=1,1=2的使用,在SQL语句组合时用的较多 V0'_PR@;
"where 1=1" 是表示选择全部 "where 1=2"全部不选, LTt|"D
如: 1$adX
if @strWhere !='' sKuPV
begin 7{:g|dX
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere _HkB+D0v
end B^sHFc""V
else 9\[A%jp#K@
begin
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 'P5|[du+
end 7]6HXR @
我们可以直接写成 PM!7ci
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere sT"h)I)]*
2、收缩数据库 {ei,>5K
--重建索引 w=S7zzL)
DBCC REINDEX (Jb[_d*
DBCC INDEXDEFRAG 8ncgTCH:
--收缩数据和日志 %l8nTcL_?
DBCC SHRINKDB "7tEk<x
DBCC SHRINKFILE 7Vxe]s
3、压缩数据库 {|Pz9a-:
dbcc shrinkdatabase(dbname) fG\]&LFBU
4、转移数据库给新用户以已存在用户权限 +
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exec sp_change_users_login 'update_one','newname','oldname' +: oD?h
go W9ewj:4\0
5、检查备份集 sCF7K=a
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' xr\wOQ*`
6、修复数据库 !rMl" Y[
ALTER DATABASE [dvbbs] SET SINGLE_USER 4$<-3IP,
GO ^>f jURR
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Ug|o($CY
GO C5jR||
ALTER DATABASE [dvbbs] SET MULTI_USER )wwQv2E
GO T c{]w?V
7、日志清除 =2=n
SET NOCOUNT ON MJ:>ZRXCE
DECLARE @LogicalFileName sysname, :,^pL At
@MaxMinutes INT, q$=EUB"C
@NewSize INT uKZe"wN;
USE tablename -- 要操作的数据库名 #Ua+P(1q
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ,lly=OhKb
@MaxMinutes = 10, -- Limit on time allowed to wrap log. e!(0y)*
@NewSize = 1 -- 你想设定的日志文件的大小(M) fC4D#
-- Setup / initialize @|^2 +K/
DECLARE @OriginalSize int =7c1l77z
SELECT @OriginalSize = size :
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FROM sysfiles hA81(JWG
WHERE name = @LogicalFileName
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + wGC)gW
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + kGZ_/"iuO
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' "jUr[X2J
FROM sysfiles K$..#]\TM
WHERE name = @LogicalFileName B R-(@
CREATE TABLE DummyTrans uUczD 8y
(DummyColumn char (8000) not null) R.EA5X|_
DECLARE @Counter INT, &)p/cOiV
@StartTime DATETIME, Y+#e| x
@TruncLog VARCHAR(255) 7gV"pa
SELECT @StartTime = GETDATE(), `[;b#.
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' <k^P>Irb3t
DBCC SHRINKFILE (@LogicalFileName, @NewSize) $MmCh&V
EXEC (@TruncLog) .qioEqK8!y
-- Wrap the log if necessary. %#Vn?zr|~
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Zbp ByRyN
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) !m#cneV
AND (@OriginalSize * 8 /1024) > @NewSize [k9aY$baT^
BEGIN -- Outer loop. $z+iB;x
SELECT @Counter = 0 [z:bnS~yiD
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 1;l&ck-Gg/
BEGIN -- update ZL`G<Mo;.
INSERT DummyTrans VALUES ('Fill Log') 2b]'KiX
DELETE DummyTrans !t["pr\
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SELECT @Counter = @Counter + 1 I,r 3.2u
END %&yD^q_
EXEC (@TruncLog) qYW{$K
END =Po!\[SBU
SELECT 'Final Size of ' + db_name() + ' LOG is ' + OKp(A
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + IA|V^Wmt;
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' pX]*&[X?
FROM sysfiles {37DrSOa
WHERE name = @LogicalFileName K'%,dn
DROP TABLE DummyTrans rSD!u0c[
SET NOCOUNT OFF |Mp_qg?g
8、说明:更改某个表 g]V}azLr
exec sp_changeobjectowner 'tablename','dbo' 1@Bq-2OD4
9、存储更改全部表 j}chU'if
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch W&]grG2/
@OldOwner as NVARCHAR(128), Z3G>DF:$
@NewOwner as NVARCHAR(128) <4y1[/S
AS -0Q:0wU
DECLARE @Name as NVARCHAR(128) 0:**uion
DECLARE @Owner as NVARCHAR(128) 7;C9V`
DECLARE @OwnerName as NVARCHAR(128) hltH{4
DECLARE curObject CURSOR FOR Lrz>0_Q
select 'Name' = name, !b*lL#s,Y
'Owner' = user_name(uid) ctOC.
from sysobjects !UD62yw~
where user_name(uid)=@OldOwner :rb<mg[
order by name P sD+?
OPEN curObject )@3ce'
FETCH NEXT FROM curObject INTO @Name, @Owner r6Z&i^cMe
WHILE(@@FETCH_STATUS=0) }(-R`.e;
BEGIN ke~O+]
if @Owner=@OldOwner _y)#N<
begin J[UL
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) 0gVylQ
exec sp_changeobjectowner @OwnerName, @NewOwner +7o3TA]-
end w?.0r6j
-- select @name,@NewOwner,@OldOwner 8^zI
FETCH NEXT FROM curObject INTO @Name, @Owner qqSk*oH~
END ASAz<H$
close curObject d'Z|+lq:
deallocate curObject Z\xR+3
GO
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10、SQL SERVER中直接循环写入数据 TD,W *(b
declare @i int !xMyk>%2
set @i=1 Rcf_31 L
while @i<30 W
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begin :gb7Py'C
insert into test (userid) values(@i) T"t3e=xA
set @i=@i+1 +J$[RxQ#
end F5.Vhg
小记存储过程中经常用到的本周,本月,本年函数 s_K:h
Dateadd(wk,datediff(wk,0,getdate()),-1) [e ;K$
Dateadd(wk,datediff(wk,0,getdate()),6) :n>m">4
Dateadd(mm,datediff(mm,0,getdate()),0) XN]kNJX
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) :SSe0ZZ_6b
Dateadd(yy,datediff(yy,0,getdate()),0) UioLu90
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) GfY!~J
上面的SQL代码只是一个时间段 _C"W;n'
Dateadd(wk,datediff(wk,0,getdate()),-1) ro6peUL*2`
Dateadd(wk,datediff(wk,0,getdate()),6) uKh),@JV
就是表示本周时间段. ]BCH9%zLj
下面的SQL的条件部分,就是查询时间段在本周范围内的: R|8)iW^
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Hbx=vLQ6
而在存储过程中 +"T?.,
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Yv9(8
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 1d|+7