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。 Y"g.IK`V
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一、基础 I0'WOV70
1、说明:创建数据库 ]b?9zeT*'l
CREATE DATABASE database-name ;E^K.6
2、说明:删除数据库 ZJW[?V\5=
drop database dbname >/$Fh:R-
3、说明:备份sql server @@G6p($
--- 创建 备份数据的 device -e GL) M
USE master Q
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' $tqJ/:I
--- 开始 备份 T#@lDpO
BACKUP DATABASE pubs TO testBack K$ }a8rH
4、说明:创建新表
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) xgu `Q`~
根据已有的表创建新表: ENVk{QE!
A:create table tab_new like tab_old (使用旧表创建新表) #18 FA|
B:create table tab_new as select col1,col2... from tab_old definition only d~J-|yyT
5、说明:删除新表 Hy:V`>
drop table tabname B5%n(,Lx
6、说明:增加一个列 72uz<i!&$
Alter table tabname add column col type {V19Zv"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。 #SVNHpx
7、说明:添加主键: Alter table tabname add primary key(col) T=f|,sK +7
说明:删除主键: Alter table tabname drop primary key(col) C G\tQbum
8、说明:创建索引:create [unique] index idxname on tabname(col....) CK+d!Eg
删除索引:drop index idxname @&F@I3`{
注:索引是不可更改的,想更改必须删除重新建。 {=2DqkTD
9、说明:创建视图:create view viewname as select statement G.VuKsP]
删除视图:drop view viewname p/Sbt/R
10、说明:几个简单的基本的sql语句 z+}QZ>
选择:select * from table1 where 范围 ~+X9g
插入:insert into table1(field1,field2) values(value1,value2) CbBSFKM
删除:delete from table1 where 范围 e> rRTN
更新:update table1 set field1=value1 where 范围 wBj-m
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料!
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排序:select * from table1 order by field1,field2 [desc] .0 )Y
总数:select count as totalcount from table1 Rgy-OA
求和:select sum(field1) as sumvalue from table1 f>o,N{|
平均:select avg(field1) as avgvalue from table1 inb^$v
最大:select max(field1) as maxvalue from table1 ^[E'1$D
最小:select min(field1) as minvalue from table1 Ox!U8g8c
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11、说明:几个高级查询运算词 +yob)%
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A: UNION 运算符 s'aip5P
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。 wFh8?Z3u_
B: EXCEPT 运算符 [D"t~QMr
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。 Y}*\[}l:&x
C: INTERSECT 运算符 'nQVj
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。 7tM9u5FF
注:使用运算词的几个查询结果行必须是一致的。 EJ}!F?o
12、说明:使用外连接 g>0XxjP4
A、left outer join: B$3 ?K
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 gJiK+&8I
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c -$VZtex
B:right outer join: dCe4u<so\
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。 5<pftTcZ
C:full outer join: MTER(L
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。 mP38T{
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二、提升 F;ZSzWq
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ,d+fDmm3
法一:select * into b from a where 1<>1 zJDSbsc$%
法二:select top 0 * into b from a qSqI7ptA\
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) keW~ NM
insert into b(a, b, c) select d,e,f from b; PP~rn fE
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) -4rDbDsr
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 kd:$oS_*s
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 1be %G [*
4、说明:子查询(表名1:a 表名2:b) 1axQ)},o@p
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) Ab%;Z5$fr
5、说明:显示文章、提交人和最后回复时间 _\PNr.D8
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b >SN|?|2U/
6、说明:外连接查询(表名1:a 表名2:b) -4w=s|#.\
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c PjT=$]
7、说明:在线视图查询(表名1:a ) 1(zsOeX
select * from (SELECT a,b,c FROM a) T where t.a > 1; H7Uli]e3
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 p^nL&yIW,%
select * from table1 where time between time1 and time2 E9|eu\
select a,b,c, from table1 where a not between 数值1 and 数值2 4h!f/aF'
9、说明:in 的使用方法 ,/&'m13b/L
select * from table1 where a [not] in ('值1','值2','值4','值6') l.\re"Q
10、说明:两张关联表,删除主表中已经在副表中没有的信息 (bOpV>\Q7
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Tu{&v'!j6
11、说明:四表联查问题: f'I z
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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 ..... .x`M<L#M(
12、说明:日程安排提前五分钟提醒 \;-fi.Hrf$
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 |6UtW{2I/
13、说明:一条sql 语句搞定数据库分页 [ xOzzp4
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 ;=j@,
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14、说明:前10条记录 k:2QuG^
select top 10 * form table1 where 范围 EV#MQM
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.) tt?58dm|
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) -7/s]9o'
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[-.OI
(select a from tableA ) except (select a from tableB) except (select a from tableC) JXG"M#{
17、说明:随机取出10条数据 hmx=
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select top 10 * from tablename order by newid() 9][(Iu]h7
18、说明:随机选择记录 n,eJ$2!J
select newid() YSJy`
19、说明:删除重复记录 ,P'P^0qJ
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) >&g}7d%
20、说明:列出数据库里所有的表名 Rj F'x
select name from sysobjects where type='U' QIN."&qC^
21、说明:列出表里的所有的 ri`R<l8
select name from syscolumns where id=object_id('TableName') $@d9<83=
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 d_n7k g+
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type ;N B:e
显示结果: <2!v(EkI
type vender pcs >{eCh$L
电脑 A 1 nzjkX4KV
电脑 A 1 FJ*i\Q/D
光盘 B 2 ]sz3]"2
光盘 A 2 l$K,#P<)
手机 B 3 AM"Nn
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手机 C 3 4!asT;`'
23、说明:初始化表table1 Uie?9&3
TRUNCATE TABLE table1 O20M[_S
24、说明:选择从10到15的记录
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc )eUW5
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三、技巧 Y+4o B
1、1=1,1=2的使用,在SQL语句组合时用的较多 8ul&x~2;X
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ;!o]wHmA
如: *5zrZ]^
if @strWhere !='' "fg](Cp[z
begin cJM:
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere S[tE&[$(p
end nf1#tlIJd
else IchCACK
begin hlu:=<B
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ,+qVu,
end hjO*~
我们可以直接写成 WwC 5!kZ
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere K =.%$A
2、收缩数据库 w;Q;[:y
--重建索引 c PgfTT
DBCC REINDEX 2&+#Vsm`V
DBCC INDEXDEFRAG Auy_K?he]
--收缩数据和日志 T081G`li
DBCC SHRINKDB J7C4V'_
DBCC SHRINKFILE {_(\`>
3、压缩数据库 as=m`DqOh
dbcc shrinkdatabase(dbname) =0@&GOq
4、转移数据库给新用户以已存在用户权限 &t5{J53
exec sp_change_users_login 'update_one','newname','oldname' !-m&U4Ku6o
go #j@71]GI
5、检查备份集 V{|}}b?w?
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 2tROT][J%
6、修复数据库 eI1GXQ%
ALTER DATABASE [dvbbs] SET SINGLE_USER aNyvNEV3C
GO ^xf<nNF:p
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK axHK_1N{
GO )CX4kPj
ALTER DATABASE [dvbbs] SET MULTI_USER 0y<wvLv2C
GO 7W6cM%_B
7、日志清除 g}p;\o
SET NOCOUNT ON V\V)<BARe
DECLARE @LogicalFileName sysname, iK?b~Q
@MaxMinutes INT, i,13b
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@NewSize INT [1 Ydo`
USE tablename -- 要操作的数据库名 &V|>dLT>A
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 5Z4-Z
@MaxMinutes = 10, -- Limit on time allowed to wrap log. |QV!-LK
@NewSize = 1 -- 你想设定的日志文件的大小(M) LqdY Qd51
-- Setup / initialize 0O k,oW{
DECLARE @OriginalSize int & cNy
SELECT @OriginalSize = size }F+zs*S
FROM sysfiles Qu,8t8
WHERE name = @LogicalFileName d:G]1k;z
SELECT 'Original Size of ' + db_name() + ' LOG is ' + P}.7Mehf
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + AxxJk"v'y
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' m/N dJMoN=
FROM sysfiles 3] 1-M
WHERE name = @LogicalFileName OB~X/
CREATE TABLE DummyTrans "O8gJ0e
(DummyColumn char (8000) not null) IVlf=k
DECLARE @Counter INT, )
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@StartTime DATETIME, +UJuB
@TruncLog VARCHAR(255) _C\[DR0n
SELECT @StartTime = GETDATE(), zI~owK)%Z
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 47r_y\U h
DBCC SHRINKFILE (@LogicalFileName, @NewSize) g%u&Zkevx
EXEC (@TruncLog) `OymAyEYQ
-- Wrap the log if necessary. ~}K5#<
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 8q`$y$06Dk
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) K78rg/`
AND (@OriginalSize * 8 /1024) > @NewSize 8 6f2'o+
BEGIN -- Outer loop. CF|]e:
SELECT @Counter = 0 *&Z7m^`FQ
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) WvHw{^(lF
BEGIN -- update (HoqR
INSERT DummyTrans VALUES ('Fill Log') ,G#.BLH
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DELETE DummyTrans N_L,]QT?
SELECT @Counter = @Counter + 1 cI]WrI2CQa
END l"n{.aL
EXEC (@TruncLog) smG>sEp2
END CE15pNss
SELECT 'Final Size of ' + db_name() + ' LOG is ' + IlX$YOf4
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + r%DFve:%
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' /~4"No@
FROM sysfiles ]nhr+;of/-
WHERE name = @LogicalFileName >:=|L%]s;\
DROP TABLE DummyTrans CIjZG ?A
SET NOCOUNT OFF LJX-AO.4
8、说明:更改某个表 )} DUMq7
exec sp_changeobjectowner 'tablename','dbo' pf4 ^Bk}e
9、存储更改全部表 e T'nl,e|
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Vtppuu$
@OldOwner as NVARCHAR(128), 0?WcoPU
@NewOwner as NVARCHAR(128) v){ .Z^_C
AS Nr2 C@FU:0
DECLARE @Name as NVARCHAR(128) RFh"&0[
DECLARE @Owner as NVARCHAR(128) rQTr8DYH
DECLARE @OwnerName as NVARCHAR(128) J8y0d1SG
DECLARE curObject CURSOR FOR \,!QJp4
select 'Name' = name, \.XLcz
'Owner' = user_name(uid) Q4t(@0e}
from sysobjects 8 i&_Jgmr
where user_name(uid)=@OldOwner Y-ux7F{=z
order by name ]CU]pK?nq
OPEN curObject >r &;3:"
FETCH NEXT FROM curObject INTO @Name, @Owner >h Y"
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WHILE(@@FETCH_STATUS=0) }AZc8o-
BEGIN
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if @Owner=@OldOwner UZ8?[
begin nS()u}c;r
set @OwnerName = @OldOwner + '.' + rtrim(@Name) U $Qv>7
exec sp_changeobjectowner @OwnerName, @NewOwner Hn,:`mj4-6
end ,fEO>
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-- select @name,@NewOwner,@OldOwner Z -%(~
FETCH NEXT FROM curObject INTO @Name, @Owner 61U<5:#l
END ,2oF:H
close curObject C1T_9}L-A
deallocate curObject c62=* ] ,
GO ZxGP/D
10、SQL SERVER中直接循环写入数据 = sAn,ri
declare @i int uH3D{4
set @i=1 D+lzFn$3
while @i<30 lq.Te,Y%w
begin 3Q/#T1@
insert into test (userid) values(@i) B*!WrB:s
set @i=@i+1 $-+/$!
end ~-a'v!
小记存储过程中经常用到的本周,本月,本年函数 wPbkUVO
Dateadd(wk,datediff(wk,0,getdate()),-1) [6jbgW~E
Dateadd(wk,datediff(wk,0,getdate()),6) Qy#)Gxp
Dateadd(mm,datediff(mm,0,getdate()),0) 9*6]&:fm
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) }U@m*dEG
Dateadd(yy,datediff(yy,0,getdate()),0) Gf8s?l
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Ou'?]{
上面的SQL代码只是一个时间段 >Ps7I
Dateadd(wk,datediff(wk,0,getdate()),-1) ,n2i@?NHZ
Dateadd(wk,datediff(wk,0,getdate()),6) -#-p1^v}
就是表示本周时间段. +b;hBb]R
下面的SQL的条件部分,就是查询时间段在本周范围内的: (Lh#`L?x
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) G;gJNK"e
而在存储过程中 w^K^I_2ge
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) wLuv6\E
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) {|9}+
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