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。 h){ #dU+&
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一、基础 gJwX
1、说明:创建数据库 q2B'R
CREATE DATABASE database-name 4$2HO`@uN
2、说明:删除数据库 ''9K(p6
drop database dbname j4@6`[n:
3、说明:备份sql server h^IizrqU
--- 创建 备份数据的 device dwvc;f-
USE master L*Ffic
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' po]<sB
--- 开始 备份 15|gG<-
BACKUP DATABASE pubs TO testBack %T<c8w}dP
4、说明:创建新表 0.!vp?
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ""V\hHdp
根据已有的表创建新表: OS
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A:create table tab_new like tab_old (使用旧表创建新表) x5rm
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B:create table tab_new as select col1,col2... from tab_old definition only C)qG<PW.!
5、说明:删除新表 |,.1=|&u
drop table tabname a&mL Dh/
6、说明:增加一个列 ="@f~~
Alter table tabname add column col type g:c?%J
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。 I)3LJK
7、说明:添加主键: Alter table tabname add primary key(col) FDGzh/
说明:删除主键: Alter table tabname drop primary key(col) vsA/iH.
8、说明:创建索引:create [unique] index idxname on tabname(col....) z:Ru`
删除索引:drop index idxname '|tmmoY6a:
注:索引是不可更改的,想更改必须删除重新建。 a(-t"OL\
9、说明:创建视图:create view viewname as select statement 2I=4l
删除视图:drop view viewname \dB z-H'@
10、说明:几个简单的基本的sql语句 54]UfmT%I
选择:select * from table1 where 范围 tC+11M
插入:insert into table1(field1,field2) values(value1,value2) *gwo.s
删除:delete from table1 where 范围 V2m=
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更新:update table1 set field1=value1 where 范围 #cJ1Jj $
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! |D;I>O^"R
排序:select * from table1 order by field1,field2 [desc] [w FK!?
总数:select count as totalcount from table1
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求和:select sum(field1) as sumvalue from table1 [m<8SOMG(
平均:select avg(field1) as avgvalue from table1 gZz5P>^
最大:select max(field1) as maxvalue from table1 2R3)/bz-SV
最小:select min(field1) as minvalue from table1 KpQ@cc
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11、说明:几个高级查询运算词 +I.{y
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A: UNION 运算符 +=kz".$
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。 ]*rK;
B: EXCEPT 运算符 *2m{i:3
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。 {|q(4(f"Iu
C: INTERSECT 运算符 PC?XE8o
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。 uH} }z !
注:使用运算词的几个查询结果行必须是一致的。 ~NK|q5(I
12、说明:使用外连接 K>2 Bz&)
A、left outer join: E@@XWU21;N
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。 v?q)E%5j
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 CY@#_z
B:right outer join: l8DZ2cw]
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。 R{Me~L?
C:full outer join: gF|u%_y-qt
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。 5.U|CL
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二、提升 |198A,^
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 0ol*!@?
法一:select * into b from a where 1<>1 SivJaY%
法二:select top 0 * into b from a @w;&:J9m
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) jQ P2[\
insert into b(a, b, c) select d,e,f from b; JjH141 n%D
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) }}d,xI
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 HUGhz
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. E*UE?4FSw|
4、说明:子查询(表名1:a 表名2:b) $_W kI^
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) 2Ni {fC?
5、说明:显示文章、提交人和最后回复时间 oMb@)7
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 843O}v'
6、说明:外连接查询(表名1:a 表名2:b) )#025>$z
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c !X<dN..
7、说明:在线视图查询(表名1:a ) 3ZL<6`Y F
select * from (SELECT a,b,c FROM a) T where t.a > 1; `R_;n#3F0
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 3m/XT"D
select * from table1 where time between time1 and time2 {} Zqaf
select a,b,c, from table1 where a not between 数值1 and 数值2 /baSAoh/e
9、说明:in 的使用方法 Ibu 5
select * from table1 where a [not] in ('值1','值2','值4','值6') KyRcZ"
10、说明:两张关联表,删除主表中已经在副表中没有的信息 j:'8yFi_
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) nW_cjYS%
11、说明:四表联查问题: GNI:k{H@"?
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 ..... T5+9#
12、说明:日程安排提前五分钟提醒 Gxh1wqLR
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 d`J~w/]
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13、说明:一条sql 语句搞定数据库分页 !TPKD
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 )8JM.:,
14、说明:前10条记录 ?%i~~hfH#N
select top 10 * form table1 where 范围 kuo!}QFL
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.) ECvTmU'=
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 7E\k97#G
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 `:YCOF
(select a from tableA ) except (select a from tableB) except (select a from tableC) ?!$:I8T
17、说明:随机取出10条数据 Ws:MbZyr
select top 10 * from tablename order by newid() 5/m}v'S%
18、说明:随机选择记录 cPPTGpqw
select newid() e4Q2$Q@b
19、说明:删除重复记录 zEs:OOM
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) D[p`1$E-1v
20、说明:列出数据库里所有的表名 7Nlk:f)*-
select name from sysobjects where type='U' FZ=xy[q]~
21、说明:列出表里的所有的 A\)~y{9bQ
select name from syscolumns where id=object_id('TableName') #9p|aS\
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。 VqnM>||
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 ~r?VXO p"
显示结果: Z6IWQo,)Rh
type vender pcs "g&hsp+i"A
电脑 A 1 ..UA*#%1
电脑 A 1 E{{Kzr2$
光盘 B 2 Ex@o&j\93
光盘 A 2 ibh,d.*~g
手机 B 3 sff4N>XAl<
手机 C 3 X
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23、说明:初始化表table1 1SSS0 &
TRUNCATE TABLE table1 r&Qq,koE
24、说明:选择从10到15的记录 tYMPqP,1.
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc "43F.!P
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三、技巧 uFn?U)
1、1=1,1=2的使用,在SQL语句组合时用的较多 0n*D](/NK
"where 1=1" 是表示选择全部 "where 1=2"全部不选, PUErvLt
如: 0?O$->t
if @strWhere !='' arN=OB
begin /n1L},67h
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere KRb'kW
end du_~P"[
else 8~ u/gM
begin w/csLi.O
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 2BV]@]qB
end %F13*hOu
我们可以直接写成 ]Wtg.y6;
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere rG3?Z^&R+
2、收缩数据库 ^o4](l
--重建索引 5:(/k\9+yv
DBCC REINDEX @S1Z"%S
DBCC INDEXDEFRAG JJy.)-R
--收缩数据和日志 Lr0:yo
DBCC SHRINKDB 8&3KVd`
DBCC SHRINKFILE m}6Jdt'|
3、压缩数据库 8&yI1XM|
dbcc shrinkdatabase(dbname) *U +<Hv`C
4、转移数据库给新用户以已存在用户权限 fGoJP[ae
exec sp_change_users_login 'update_one','newname','oldname' fNz(z\
go ch33+~Nn
5、检查备份集 izs=5
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' iw%""q(`
6、修复数据库 r+;k(HMY}[
ALTER DATABASE [dvbbs] SET SINGLE_USER oSIP{lfp2Q
GO N9 h|_ax
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK l2ie\4dK@
GO g{CU1c)B
ALTER DATABASE [dvbbs] SET MULTI_USER O_L>We@3E
GO <!F".9c@A
7、日志清除 s"R5'W\U
SET NOCOUNT ON [}yPy))A
DECLARE @LogicalFileName sysname, & H8 %
@MaxMinutes INT, 6q^\pJY%&7
@NewSize INT HvmE'O8
USE tablename -- 要操作的数据库名 Z<,Hz+
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 $gZiW 8
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 8:[ l1d86
@NewSize = 1 -- 你想设定的日志文件的大小(M) NxnaH!wS
-- Setup / initialize |AS~sjWSJ
DECLARE @OriginalSize int >>|47ps3
SELECT @OriginalSize = size "z*.Bk
FROM sysfiles 5p6/dlN-a
WHERE name = @LogicalFileName _0UE*l$t
SELECT 'Original Size of ' + db_name() + ' LOG is ' + o`G6!
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + -[}Aka,f!
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' d"L(eI}G
FROM sysfiles 6\k~q.U@XI
WHERE name = @LogicalFileName 9WI5\`*"
CREATE TABLE DummyTrans ; tQ(l%!
(DummyColumn char (8000) not null) [w!T
DECLARE @Counter INT, &XCP@@T
@StartTime DATETIME, 8 Vf#t!t
@TruncLog VARCHAR(255) f@[)*([
SELECT @StartTime = GETDATE(), TU':Rt
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' P^!g0K
DBCC SHRINKFILE (@LogicalFileName, @NewSize) LcB+L](
EXEC (@TruncLog) [XttT
-- Wrap the log if necessary. 3iUJ!gK
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired yEk|(6+^
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) v|KIVBkbT
AND (@OriginalSize * 8 /1024) > @NewSize K1o>>388G
BEGIN -- Outer loop. {]dG 9
SELECT @Counter = 0 !&:Cp_
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) l fFRqZ
BEGIN -- update }zxf~41
INSERT DummyTrans VALUES ('Fill Log') _>BYUPY
DELETE DummyTrans Zb2PFwcy
SELECT @Counter = @Counter + 1 }a#T\6rY
END %|ClYr
EXEC (@TruncLog) (P;TM1k
END fj/L)i
SELECT 'Final Size of ' + db_name() + ' LOG is ' + <VSB!:ew
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Vr Lp5?Bh
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' v*0J6<
FROM sysfiles ''D7Bat@
WHERE name = @LogicalFileName > ;#Y0
DROP TABLE DummyTrans DaJ,(DJY
SET NOCOUNT OFF 63J3NwFt
8、说明:更改某个表 8EMBqhl
exec sp_changeobjectowner 'tablename','dbo' V8nQ/9R;
9、存储更改全部表 tzfyS#E
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ij#v_~g3
@OldOwner as NVARCHAR(128), 60]VOQku
@NewOwner as NVARCHAR(128) Lq
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AS 4`mf^Kf
DECLARE @Name as NVARCHAR(128) 4w'&:k47
DECLARE @Owner as NVARCHAR(128) I'^XEl?
DECLARE @OwnerName as NVARCHAR(128) ,A7:zxnc.V
DECLARE curObject CURSOR FOR 9C2pGfEbn}
select 'Name' = name, n1GX`K
'Owner' = user_name(uid) V= p"1!(
from sysobjects tu"-]^
where user_name(uid)=@OldOwner 0Ze&GK'Hf
order by name U,7
OPEN curObject H\n6t-l
FETCH NEXT FROM curObject INTO @Name, @Owner (T$cw(!
WHILE(@@FETCH_STATUS=0) _
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BEGIN X Db% -
if @Owner=@OldOwner JP0aNu
begin -?:8sv*X
set @OwnerName = @OldOwner + '.' + rtrim(@Name) a%BC{XX
exec sp_changeobjectowner @OwnerName, @NewOwner h.]^ o*DJ
end 7Hv6>z#m
-- select @name,@NewOwner,@OldOwner 2;*G!rE&*`
FETCH NEXT FROM curObject INTO @Name, @Owner qdwo 2u
END _Dqi#0#40p
close curObject {fDRVnI?
deallocate curObject ,mvFeo;@f
GO -zMvpe-am&
10、SQL SERVER中直接循环写入数据 ~PQR_?1
declare @i int VyNF)$'T
set @i=1 "~EAt$
while @i<30 <dE~z] P
begin Z:,\FB_U
insert into test (userid) values(@i) o6|-
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set @i=@i+1 c(vi,U-hC
end ^Ss<<
小记存储过程中经常用到的本周,本月,本年函数 1|-C(UW>
Dateadd(wk,datediff(wk,0,getdate()),-1) 3I)oqS@q'
Dateadd(wk,datediff(wk,0,getdate()),6) m*HUT V
Dateadd(mm,datediff(mm,0,getdate()),0)
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 4clCZ@\K^
Dateadd(yy,datediff(yy,0,getdate()),0) 5uSg]2:
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) GHLnwym
上面的SQL代码只是一个时间段 uEr.LCAS
Dateadd(wk,datediff(wk,0,getdate()),-1) <_pLmYI
Dateadd(wk,datediff(wk,0,getdate()),6) muF&t'k
就是表示本周时间段. |5FEsts[
下面的SQL的条件部分,就是查询时间段在本周范围内的: K%BFR,)g
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) )v+&l9D
而在存储过程中 -{JReplc
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) --TH6j"
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) P|?nx"c