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。 k)K-mD``U
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一、基础 #"8[8jyV
1、说明:创建数据库 ^%%5
CREATE DATABASE database-name 7(~H77
2、说明:删除数据库 t?nc0;Q9,@
drop database dbname }j(2Dl
3、说明:备份sql server %;\G@q_p{
--- 创建 备份数据的 device DGZY~(]
USE master C{hcK 1-K
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' iqednk%
--- 开始 备份 0 {JK4]C
BACKUP DATABASE pubs TO testBack <VaMUm<2
4、说明:创建新表 ?
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) >6I.%!jU
根据已有的表创建新表: /uE^H%9h
A:create table tab_new like tab_old (使用旧表创建新表) )Bn>/-
B:create table tab_new as select col1,col2... from tab_old definition only h [IYA1/y
5、说明:删除新表 {y:#'n
drop table tabname q|u8CX
6、说明:增加一个列 O GFE*
Alter table tabname add column col type !-5S8b
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。 9S1Ti6A
7、说明:添加主键: Alter table tabname add primary key(col) +~4bB$6*4)
说明:删除主键: Alter table tabname drop primary key(col) W>0"CUp
8、说明:创建索引:create [unique] index idxname on tabname(col....) ;sChxQ=.^
删除索引:drop index idxname |#&V:GZp
注:索引是不可更改的,想更改必须删除重新建。 mUt,Z^ l`
9、说明:创建视图:create view viewname as select statement A} -&C
删除视图:drop view viewname 9fuJJ3L[
10、说明:几个简单的基本的sql语句 T")i+v
选择:select * from table1 where 范围 l7'{OB
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插入:insert into table1(field1,field2) values(value1,value2) m(Y.X=EZr
删除:delete from table1 where 范围 c3V]'~
更新:update table1 set field1=value1 where 范围 7V=MRf&xQ
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ; wbUk5Tf/
排序:select * from table1 order by field1,field2 [desc] L%WME8PB
总数:select count as totalcount from table1 }(ma__Ao
求和:select sum(field1) as sumvalue from table1 }. xrJ52Tz
平均:select avg(field1) as avgvalue from table1 ~ThVap[*
最大:select max(field1) as maxvalue from table1 {xv?wenE
最小:select min(field1) as minvalue from table1 $U>/i@ D
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11、说明:几个高级查询运算词 n5v'
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A: UNION 运算符 hj&fQ}X
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 j ,C,5l=
B: EXCEPT 运算符 V06CCy8n
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 SOp=~z
C: INTERSECT 运算符 oTCzY Y
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 /2;dH]o0
注:使用运算词的几个查询结果行必须是一致的。 iuC7Y|
12、说明:使用外连接 U@6jOZ
A、left outer join: +Qh[sGDdY
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 b mOqeUgB
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c N0Efw$u
B:right outer join: 0n:?sFY>
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。 J7BFk
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C:full outer join: /gz:zThf{
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。 yiVG ]s
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二、提升 Y?yo\(Cdx
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) .u1X+P7
法一:select * into b from a where 1<>1 Al7<s
法二:select top 0 * into b from a A4G,}r *n
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) n/QfdAg
insert into b(a, b, c) select d,e,f from b; J["H[T*
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) xvU]jl6d
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 fb\DiKsW
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. X8/Tl\c
4、说明:子查询(表名1:a 表名2:b) R?cUy8?'S
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) Sd},_Kh
5、说明:显示文章、提交人和最后回复时间 q|5Q?t:,r
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b CqqXVF3
6、说明:外连接查询(表名1:a 表名2:b) xS'zZ%?
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c &lAQ &
7、说明:在线视图查询(表名1:a ) A\K,_&x1Z
select * from (SELECT a,b,c FROM a) T where t.a > 1; s]U4B<q
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 #(C/Cx54
select * from table1 where time between time1 and time2 ![ZmV
select a,b,c, from table1 where a not between 数值1 and 数值2 Nl@k*^
9、说明:in 的使用方法 /aZE,IeEz
select * from table1 where a [not] in ('值1','值2','值4','值6') Sp:l;SGd
10、说明:两张关联表,删除主表中已经在副表中没有的信息 >1 @Ltvm
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Y\xUT>(J7
11、说明:四表联查问题: _\.{6""
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 ..... <I;5wv
12、说明:日程安排提前五分钟提醒 %Rp8{.t7
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 7^$)VBQ/
13、说明:一条sql 语句搞定数据库分页 {`%hgR
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 fN-Gk(Ic
14、说明:前10条记录 mEFw|M{
select top 10 * form table1 where 范围 V8hO8
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) hSB?@I4s<\
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) |uI?ySF
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 uWjN2#&,
(select a from tableA ) except (select a from tableB) except (select a from tableC) wu)Wg-dT
17、说明:随机取出10条数据 B**Nn!}0
select top 10 * from tablename order by newid() zB*euHIqZ
18、说明:随机选择记录 %_MEfuL
select newid() Qzqc .T
19、说明:删除重复记录 u-JpI-8h
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 1<.5ub*i4
20、说明:列出数据库里所有的表名 FJeiY#us
select name from sysobjects where type='U' ESTM$k}X
21、说明:列出表里的所有的 0:"2MSf>
select name from syscolumns where id=object_id('TableName') y6-XHeU
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。 O0T/#<Cn!
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 $7Z)Yp&T
显示结果: d "E^SBO&
type vender pcs +m)q% I>
电脑 A 1 Ipe n
电脑 A 1 Ooc\1lX
光盘 B 2 w##^}nHOR
光盘 A 2 |4;UyHh
手机 B 3 c6&Q^p|CF
手机 C 3 OcmRZ
23、说明:初始化表table1 <YB9Ac~}z
TRUNCATE TABLE table1 :z&7W<
24、说明:选择从10到15的记录 h|D0z_f
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc }^xE|~p
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三、技巧 [;A[.&6
1、1=1,1=2的使用,在SQL语句组合时用的较多 &c>?~-!W
"where 1=1" 是表示选择全部 "where 1=2"全部不选, u JY)4T
如: GbI-SbE
if @strWhere !='' y7/F_{
begin AY,].Zg[
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere *JX;|S
end k*?I>%^6#T
else ~q+hV+fa>
begin ?QZ"JX])
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' $q$7^r@
end bQ'8SCe
我们可以直接写成 jYRP8 Yi
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere A\fb<
2、收缩数据库 x/!5K|c
--重建索引 g[H',)A)
DBCC REINDEX asHxL!
DBCC INDEXDEFRAG tM4Cx
--收缩数据和日志 0@I S
DBCC SHRINKDB 2ZcKK8X;7
DBCC SHRINKFILE D^Jk@<*
3、压缩数据库 |`TgX@,#9
dbcc shrinkdatabase(dbname) >J9oH=S6
4、转移数据库给新用户以已存在用户权限 ]\ !5}L
exec sp_change_users_login 'update_one','newname','oldname' F$BbYf2i
go 1y#D?R=E
5、检查备份集 YNwp/Y
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' .*g0w`H5pU
6、修复数据库 JN+_|`
ALTER DATABASE [dvbbs] SET SINGLE_USER _g%TSumvq<
GO kF(n!2"W
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK v6.t{6zYgY
GO AIMSX]m
ALTER DATABASE [dvbbs] SET MULTI_USER ljTBvU
GO `F<jLU^3
7、日志清除 .p0Clr!
SET NOCOUNT ON 2 3OC2|
DECLARE @LogicalFileName sysname, }>)[<;M>%
@MaxMinutes INT, pRkP~ZISU
@NewSize INT P3$Q&^?
USE tablename -- 要操作的数据库名 8J$|NYv_b
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 >
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. =[b)1FUp
@NewSize = 1 -- 你想设定的日志文件的大小(M)
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-- Setup / initialize M5gWD==uP
DECLARE @OriginalSize int p
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SELECT @OriginalSize = size .o) `m9/
FROM sysfiles QQWadVQo
WHERE name = @LogicalFileName :oJ=iB'Zc
SELECT 'Original Size of ' + db_name() + ' LOG is ' + Z#rB}
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + R(q~ -3~
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' /p8dZ+X
FROM sysfiles ^fZ&QK
WHERE name = @LogicalFileName BNL;Biyt7
CREATE TABLE DummyTrans +v=C@2T
(DummyColumn char (8000) not null) dqN5]Sb2B
DECLARE @Counter INT, yUpgoX(6
@StartTime DATETIME, ,7<f9 EVY
@TruncLog VARCHAR(255) [VE8V-
SELECT @StartTime = GETDATE(), 7(pF[LCF
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 6Vz9?puD
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 4^M
EXEC (@TruncLog) euC&0Ee2
-- Wrap the log if necessary. oH_;4QU4y
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired rk #sy$
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ?#fu.YE\
AND (@OriginalSize * 8 /1024) > @NewSize Za1QC;7
BEGIN -- Outer loop. 8P|D13- Q
SELECT @Counter = 0 >r !|sC
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) B]Thn
BEGIN -- update 0N$v"uX@
INSERT DummyTrans VALUES ('Fill Log') >Wv;R2|
DELETE DummyTrans O6LS(5j2
SELECT @Counter = @Counter + 1 ev*k*0
END @0/+_2MH-
EXEC (@TruncLog) R^Y
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END |'B7v i)
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Z'.AA OG
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Sy0$z39
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' eQ]~dA8>
FROM sysfiles ivN&HAxI@
WHERE name = @LogicalFileName _sTROd)Vh
DROP TABLE DummyTrans Y2~nBb
SET NOCOUNT OFF rR(X9i
8、说明:更改某个表 }f6HYU
exec sp_changeobjectowner 'tablename','dbo' E?
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9、存储更改全部表 7_inJ$
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch "i[@P)
@OldOwner as NVARCHAR(128), DK:o]~n
@NewOwner as NVARCHAR(128) [q8 P~l
AS -C(crn
DECLARE @Name as NVARCHAR(128) :%,:"
DECLARE @Owner as NVARCHAR(128) Yfzl%wc
DECLARE @OwnerName as NVARCHAR(128) JehrDC2N
DECLARE curObject CURSOR FOR j~[z2tV
select 'Name' = name, %[ Z \S0C
'Owner' = user_name(uid) rrik,qyv6
from sysobjects JR@`2YP-
where user_name(uid)=@OldOwner KUlp"{a`,K
order by name G}b]w~ML~
OPEN curObject of%Ktm5Qi
FETCH NEXT FROM curObject INTO @Name, @Owner Y[}>CYO
WHILE(@@FETCH_STATUS=0) Ch<[l8;K
BEGIN L.*M&Ry
if @Owner=@OldOwner ,9zjFI
begin A>o*t=5
set @OwnerName = @OldOwner + '.' + rtrim(@Name) M_/7D|xl/T
exec sp_changeobjectowner @OwnerName, @NewOwner 7QiIiWqIWC
end YIQ
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-- select @name,@NewOwner,@OldOwner A$Hfr8w1u
FETCH NEXT FROM curObject INTO @Name, @Owner \`~Ly-
END jaII r06
close curObject 7&jTtKLj
deallocate curObject f!Y?S
GO a|t$l=|DD
10、SQL SERVER中直接循环写入数据 sBvzAVBL
declare @i int `yrB->|vG
set @i=1 I9_RlAd
while @i<30 g+vva"
begin 4xjP iHd<
insert into test (userid) values(@i) tkeoNuAM
set @i=@i+1 PUp6Q;AdQ
end EE&K0<?T|:
小记存储过程中经常用到的本周,本月,本年函数 ,8U&?8l
Dateadd(wk,datediff(wk,0,getdate()),-1) @\0ez<.p}
Dateadd(wk,datediff(wk,0,getdate()),6) H1|?t+oP
Dateadd(mm,datediff(mm,0,getdate()),0) `VA"vwz
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) =_JjmTy;a
Dateadd(yy,datediff(yy,0,getdate()),0) 2=,lcWr
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 4gI/!,J(b
上面的SQL代码只是一个时间段 <wN}X#M
Dateadd(wk,datediff(wk,0,getdate()),-1) bh,[ 3X%
Dateadd(wk,datediff(wk,0,getdate()),6) g:g\>@Umo
就是表示本周时间段. Xv ]W(f1
下面的SQL的条件部分,就是查询时间段在本周范围内的: P+@/O
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) x
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而在存储过程中 )WNzWUfn=z
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) CGW.I$u
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) LO9=xGj.