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。 NNUm=g^
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一、基础 4BSSJ@z
1、说明:创建数据库 nx<q]Juv\
CREATE DATABASE database-name Z$h39hm?c
2、说明:删除数据库 &^-quzlZ
drop database dbname K>H_q@-?f
3、说明:备份sql server X2#;1 ku
--- 创建 备份数据的 device Oh9jr"Gm=
USE master :hB
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' -u6`B-T
--- 开始 备份 23a&m04Rk
BACKUP DATABASE pubs TO testBack YE#OAfj~
4、说明:创建新表 GdN'G
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ^s'ozCk 0
根据已有的表创建新表: 2+G_Y>
A:create table tab_new like tab_old (使用旧表创建新表) XWo=?(iA
B:create table tab_new as select col1,col2... from tab_old definition only {ZK"K+;h
5、说明:删除新表 UH8)r
drop table tabname E|f&SEnzK
6、说明:增加一个列 a8fLj
Alter table tabname add column col type $ohg?B;
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 VN=S&iBa/
7、说明:添加主键: Alter table tabname add primary key(col) WZ"g:Khw
说明:删除主键: Alter table tabname drop primary key(col) aOYRenqu
8、说明:创建索引:create [unique] index idxname on tabname(col....) VK9I#
删除索引:drop index idxname E|2klA^+*
注:索引是不可更改的,想更改必须删除重新建。 'c#ZW|A
9、说明:创建视图:create view viewname as select statement w}Q|*!?_
删除视图:drop view viewname &HKrmFgX{
10、说明:几个简单的基本的sql语句 xe)< )y
选择:select * from table1 where 范围 wzAp`Zs2Dm
插入:insert into table1(field1,field2) values(value1,value2) 7S<Z&1(
删除:delete from table1 where 范围 ?3tR(H<
更新:update table1 set field1=value1 where 范围 A/NwM1z[o)
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! "yMr\jt~-
排序:select * from table1 order by field1,field2 [desc] 6"Tr$E
总数:select count as totalcount from table1 p-U'5<n
求和:select sum(field1) as sumvalue from table1 Xg#g`m%(M
平均:select avg(field1) as avgvalue from table1 ~mUP!f
最大:select max(field1) as maxvalue from table1 |L{<=NNs:D
最小:select min(field1) as minvalue from table1 GXaCH))TO
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11、说明:几个高级查询运算词 UQz8":#V
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A: UNION 运算符 O2{_:B>K[
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。 x9PEYhL?
B: EXCEPT 运算符 !F{ 5"$
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。 * wN+Ak q
C: INTERSECT 运算符 UP:+1Sp9
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。 &libC>a[
注:使用运算词的几个查询结果行必须是一致的。 x@bZ((w
12、说明:使用外连接 BY:
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A、left outer join: whP>'9t.w
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。 (E)/' sEb
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 Xmy(pV!PF
B:right outer join: ]4@z.1Mr
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。 Dbr(Wg
C:full outer join: st36xS
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。 /IVw}:G
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二、提升 m^_)aS
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 'w.:I
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法一:select * into b from a where 1<>1 avls[Bq
法二:select top 0 * into b from a }vO^%Gd
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) }/G~"&N[
insert into b(a, b, c) select d,e,f from b; 5}e-~-
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) lqPRUkin
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 9&}qie,
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 2q# t/oN3T
4、说明:子查询(表名1:a 表名2:b) 9a)D8
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) Dbyy H_
5、说明:显示文章、提交人和最后回复时间 _p{ag
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select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 'dj}- Rs
6、说明:外连接查询(表名1:a 表名2:b) T$%u=$E%F
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c `A80""y:M
7、说明:在线视图查询(表名1:a ) ?AY596
select * from (SELECT a,b,c FROM a) T where t.a > 1; (FMG W
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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 /S9Mu
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select * from table1 where time between time1 and time2 R4}G@&Q
select a,b,c, from table1 where a not between 数值1 and 数值2 13A11XTp
9、说明:in 的使用方法 7w)#[^
select * from table1 where a [not] in ('值1','值2','值4','值6') >FHTBh& Y
10、说明:两张关联表,删除主表中已经在副表中没有的信息 c[ff|-<g
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ZvNXfC3Ia
11、说明:四表联查问题: Uk ?V7?&
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 ..... oTOe(5N8a
12、说明:日程安排提前五分钟提醒 }W<]fK
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 sr#,S(p
13、说明:一条sql 语句搞定数据库分页 &nPv%P,e
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 =KT7ZSTV
14、说明:前10条记录 NLb/Bja
select top 10 * form table1 where 范围 D'O[0?N"g
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.) z[qM2
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) hFa\x5I5
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 4)9X) Qx
(select a from tableA ) except (select a from tableB) except (select a from tableC) aqs']
17、说明:随机取出10条数据 x#dJH9NR[
select top 10 * from tablename order by newid() @R}L
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18、说明:随机选择记录 Q+ G=f
select newid() 7"4|`y^#
19、说明:删除重复记录 @c$mc
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) e5fJN)+a
20、说明:列出数据库里所有的表名 !l6B_[!@
select name from sysobjects where type='U' >E"FoZM=
21、说明:列出表里的所有的 |#5JI#,vX
select name from syscolumns where id=object_id('TableName') ]2zx}D4f
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 v}[KVwse
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type xNxIqq<k
显示结果: %XG X(
type vender pcs 7F?^gMi
电脑 A 1 ;
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电脑 A 1 &$hfAG]"
光盘 B 2 :CHCVoh@95
光盘 A 2 XNu2G19jb
手机 B 3 KU33P>a"[k
手机 C 3 R52q6y:<x
23、说明:初始化表table1 "@`mPe/
TRUNCATE TABLE table1 ,\}V.:THF
24、说明:选择从10到15的记录 ;5y4v
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc "cJ5Fd:*
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三、技巧 lt0(Kf g
1、1=1,1=2的使用,在SQL语句组合时用的较多 b'9G`Y s^
"where 1=1" 是表示选择全部 "where 1=2"全部不选, G=Ka{J
如: D zDt:.JZ
if @strWhere !='' |7%$+g
begin 3L>V-RPi M
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere aeUm,'Y$
end JpS:}yyJ>N
else by6E
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begin `5 e#9@/e
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' NqqLRgMOR'
end _rjCwo\
我们可以直接写成 |k
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere >>^c_ 0"O
2、收缩数据库 oF,8j1
--重建索引 , is
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DBCC REINDEX VdK-2O(.-
DBCC INDEXDEFRAG W97Ka}Y
--收缩数据和日志 >+oQxml6nI
DBCC SHRINKDB ,st4K;-
DBCC SHRINKFILE $#Ji=JX
3、压缩数据库 u> >t"w
dbcc shrinkdatabase(dbname) 0HxF#SlKM
4、转移数据库给新用户以已存在用户权限 -JwH^*Ad
exec sp_change_users_login 'update_one','newname','oldname' >b*Pd
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go |Ca$>]?
5、检查备份集 {8I93]
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 2?-}(F;Z
6、修复数据库 ol`]6"Sc
ALTER DATABASE [dvbbs] SET SINGLE_USER ^Gs!" Y
GO kf5921(P
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ;ejC:3yO
GO ZTS*E,U%
ALTER DATABASE [dvbbs] SET MULTI_USER Ti' GSL
GO %8{' XJ!
7、日志清除 yY_]YeeR
SET NOCOUNT ON =~aJ]T}(
DECLARE @LogicalFileName sysname, ?# G_&
@MaxMinutes INT, cVulJ6
@NewSize INT ^O892 -R
USE tablename -- 要操作的数据库名 2N)vEUyDV
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 k7W8$8v
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 8%nTDSp&t
@NewSize = 1 -- 你想设定的日志文件的大小(M) g>f(5
-- Setup / initialize ;utjW1y
DECLARE @OriginalSize int aUA+%
SELECT @OriginalSize = size dd4yS}yBlR
FROM sysfiles PS=crU@"H
WHERE name = @LogicalFileName r&ToUU 5
SELECT 'Original Size of ' + db_name() + ' LOG is ' + F1Z20)8K
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + A0[flIl
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' yobi$mnsy!
FROM sysfiles
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WHERE name = @LogicalFileName iwmXgsRa9}
CREATE TABLE DummyTrans L
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(DummyColumn char (8000) not null) >J8?n,*
DECLARE @Counter INT, EKoCm)}d
@StartTime DATETIME, NU
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@TruncLog VARCHAR(255) 'Z&A5\~
SELECT @StartTime = GETDATE(), ?=4J
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 3rR(>}:[V
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 2,_BO6
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EXEC (@TruncLog) n!tC z<v
-- Wrap the log if necessary. {h@R\bU
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Q6vkqu5!=
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 5Vvy:<.la
AND (@OriginalSize * 8 /1024) > @NewSize
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BEGIN -- Outer loop. y5R6/*;N.
SELECT @Counter = 0 hUlFP
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) g" M1HxlV
BEGIN -- update yr;oq(&N
INSERT DummyTrans VALUES ('Fill Log') /D~
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DELETE DummyTrans +pjD{S~Y
SELECT @Counter = @Counter + 1 3d,|26I 7f
END H<FDi{
EXEC (@TruncLog) l{y~N
END %|,j'V$
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ~sA}.7
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + R(q
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB'
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FROM sysfiles C(gH}N4
WHERE name = @LogicalFileName &2) mpY8xQ
DROP TABLE DummyTrans LTa9'
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SET NOCOUNT OFF (cCB3n\20
8、说明:更改某个表 j4NS5
exec sp_changeobjectowner 'tablename','dbo' PqP)<d'/
9、存储更改全部表 myJsRb5
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch fitm*
@OldOwner as NVARCHAR(128), % l5J
@NewOwner as NVARCHAR(128) * |,V$
AS v4S|&m
DECLARE @Name as NVARCHAR(128) 'rCwPsI&4
DECLARE @Owner as NVARCHAR(128) dB1bf2'b#
DECLARE @OwnerName as NVARCHAR(128) S:R%%cy
DECLARE curObject CURSOR FOR m*a0V
select 'Name' = name, ZsV'-gu
'Owner' = user_name(uid) *~-~kv4-
from sysobjects E&"bgwav{(
where user_name(uid)=@OldOwner xwz2N5
order by name &t6L8[#yd
OPEN curObject ^,`yt^^A
FETCH NEXT FROM curObject INTO @Name, @Owner I=lA7}
WHILE(@@FETCH_STATUS=0) WRo#ZVt9$
BEGIN fd)}I23Q'
if @Owner=@OldOwner R a9/L
begin lual'~
set @OwnerName = @OldOwner + '.' + rtrim(@Name) G-;pMFP(?
exec sp_changeobjectowner @OwnerName, @NewOwner s=KA(4p
end fC81(5
-- select @name,@NewOwner,@OldOwner -$mzzYH
FETCH NEXT FROM curObject INTO @Name, @Owner jNB-FVaT
END ,D#~%kq~
close curObject t(s']r
deallocate curObject 5$9j&&R
GO pRYt.}/K
10、SQL SERVER中直接循环写入数据 e+&/Tq'2
declare @i int aFl(K\
set @i=1 EnfSVG8kB8
while @i<30 2P]r J
begin fw-LZ][
insert into test (userid) values(@i) *d)B4qG
set @i=@i+1 ;%Z)$+Z_)<
end 3 i>uKU1
小记存储过程中经常用到的本周,本月,本年函数 LdRLKE<'e
Dateadd(wk,datediff(wk,0,getdate()),-1) ="XxS|Mq3
Dateadd(wk,datediff(wk,0,getdate()),6) Q+#, VuM
Dateadd(mm,datediff(mm,0,getdate()),0) G:A`
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) O*c+TiTb
Dateadd(yy,datediff(yy,0,getdate()),0) <ZCjQkka>r
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Aw >DZ2
上面的SQL代码只是一个时间段 'Z;R!@Dm
Dateadd(wk,datediff(wk,0,getdate()),-1) 7<X_\,I
Dateadd(wk,datediff(wk,0,getdate()),6) kkh#VGh"
就是表示本周时间段. *78TT\q<
下面的SQL的条件部分,就是查询时间段在本周范围内的: .PF~8@1ju
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) m:K/)v*
而在存储过程中 A2htD!3
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) /pV^w
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) O~igwFe