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。 J:!Gf^/)
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一、基础 4E94W,1%,Y
1、说明:创建数据库 $6+P&"8
CREATE DATABASE database-name .EELR]`y7I
2、说明:删除数据库 M/I d\~
drop database dbname X64I~*
3、说明:备份sql server Rs`Y'_B
--- 创建 备份数据的 device [~0q )
USE master uw&,pq
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' #GJh:#tt^
--- 开始 备份 Qi L
BACKUP DATABASE pubs TO testBack tXuxTVhoT
4、说明:创建新表 Q(Y,p`>
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) +VFwYdW,
根据已有的表创建新表: pIjVJ9+j
A:create table tab_new like tab_old (使用旧表创建新表) meWq9:z
B:create table tab_new as select col1,col2... from tab_old definition only dQ"W~ig
5、说明:删除新表 QAw,X Z.K^
drop table tabname lt"*y.%@b
6、说明:增加一个列 3`!KndY1
Alter table tabname add column col type fN>|X\-
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 C\h<02
7、说明:添加主键: Alter table tabname add primary key(col) c3BL2>c
说明:删除主键: Alter table tabname drop primary key(col) NGzqiu"J
8、说明:创建索引:create [unique] index idxname on tabname(col....) {iteC
删除索引:drop index idxname .OUE'5e p
注:索引是不可更改的,想更改必须删除重新建。 )eyxAg
9、说明:创建视图:create view viewname as select statement >gl <$LQ?X
删除视图:drop view viewname t9l7
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10、说明:几个简单的基本的sql语句 VAzJclB
选择:select * from table1 where 范围 i`spM<iR.
插入:insert into table1(field1,field2) values(value1,value2) SZ){1Hu
删除:delete from table1 where 范围 D'+8]B
更新:update table1 set field1=value1 where 范围 >C66X?0cd
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 1W7BN~p14
排序:select * from table1 order by field1,field2 [desc] ~;s)0M
总数:select count as totalcount from table1 00TdX|V`
求和:select sum(field1) as sumvalue from table1 6S&YL
平均:select avg(field1) as avgvalue from table1 |`/uS;O
最大:select max(field1) as maxvalue from table1 m^+~pC5
最小:select min(field1) as minvalue from table1 YtQWArX,
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11、说明:几个高级查询运算词 k"c_x*f
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A: UNION 运算符 ^a5>`W
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"4 6_>
B: EXCEPT 运算符 {P+[CO
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。 Puh&F< B
C: INTERSECT 运算符 ?Ea"%z*c5
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。 u{z{3fW_
注:使用运算词的几个查询结果行必须是一致的。 'kK%sE
12、说明:使用外连接 oPBjsQ
A、left outer join: `7ZJB$7D|*
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 '& :"/4@)
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c gV;GC{pY
B:right outer join: '+wTrW m~j
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 bc-)y3gHU
C:full outer join: vL0Ol-Vt
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 :Aw VeX@
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二、提升 z`SkKn0f
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) j&5Xjl>4
法一:select * into b from a where 1<>1 :Yqa[._AF
法二:select top 0 * into b from a _Ohq'ZgXm
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) r1]e:
insert into b(a, b, c) select d,e,f from b; @xEQ<g
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) J>35q'nN]F
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 T(DE^E@a
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. hrF4 a$
4、说明:子查询(表名1:a 表名2:b) t"fD"Xpj
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) 1doqznO
5、说明:显示文章、提交人和最后回复时间 K(2s%
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b QeoDq
6、说明:外连接查询(表名1:a 表名2:b) DAi[3`C
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c t1S~~FLE
7、说明:在线视图查询(表名1:a ) Qt 2hb
select * from (SELECT a,b,c FROM a) T where t.a > 1; ^p/mJ1/s7
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 cO9Aw !
select * from table1 where time between time1 and time2 2hP8ZfvIR
select a,b,c, from table1 where a not between 数值1 and 数值2 ~O6=dR
9、说明:in 的使用方法 Is[0ri
select * from table1 where a [not] in ('值1','值2','值4','值6') ":ycyN@g
10、说明:两张关联表,删除主表中已经在副表中没有的信息 79_MP
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Viw3 /K
11、说明:四表联查问题: =KLYR UW
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 ..... Dl{Pd`D
12、说明:日程安排提前五分钟提醒 ,d#4Ib
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 cALs;)z
13、说明:一条sql 语句搞定数据库分页 %s>E@[s
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 /Z_QCj
14、说明:前10条记录 75f.^4/%
select top 10 * form table1 where 范围 "?SnA +)
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.) v},sWjv
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ZtDpCl_
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 ?|\Lm3%J
(select a from tableA ) except (select a from tableB) except (select a from tableC) h>?OWI
17、说明:随机取出10条数据 kTV D4Z=
select top 10 * from tablename order by newid() zAewE@N#_
18、说明:随机选择记录 p20Nk$.
select newid() V5+a[`]
19、说明:删除重复记录 &PX'=UT
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 0'uj*Y{L
20、说明:列出数据库里所有的表名 hkG<I';M?M
select name from sysobjects where type='U' 0ZN/-2c A#
21、说明:列出表里的所有的 mf#oa~_
select name from syscolumns where id=object_id('TableName') q`hg@uwA{`
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 wlJ1,)n^2
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type #A!0KN;GC2
显示结果: cf9y0
type vender pcs {;U:0BPI3
电脑 A 1 Nsq%b?#
电脑 A 1 =[kv@p
光盘 B 2 .PgkHb=l@
光盘 A 2 *6L^A`_1]
手机 B 3 uY,FugWbl
手机 C 3 x/~M=][tN
23、说明:初始化表table1 &BkNkb 0
TRUNCATE TABLE table1 ~gN'";1i
24、说明:选择从10到15的记录 }O/Nn0,
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc {8Ll\j@ "
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三、技巧 jo;n~>3P
1、1=1,1=2的使用,在SQL语句组合时用的较多 /Q-!><riD
"where 1=1" 是表示选择全部 "where 1=2"全部不选, PLD!BD
如: )8;'fE[p}
if @strWhere !='' bHCd|4e,2
begin Vq\6c
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere tyh%s"
end 15COwc*k
else 0^=S:~G
begin i!NGX
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' n2E2V<#
end s=:n<`Z2
我们可以直接写成 zv41Yv!x}
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere @azS)4L
2、收缩数据库 x{m)I<.:
--重建索引 4[?Q*f!
DBCC REINDEX ep5aBrN]"
DBCC INDEXDEFRAG L>B0%TP^
--收缩数据和日志 GCrN:+E0FJ
DBCC SHRINKDB N`M5`=.
DBCC SHRINKFILE xK/`XY
3、压缩数据库 wgrYZ^]
dbcc shrinkdatabase(dbname) rO
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4、转移数据库给新用户以已存在用户权限 Hl#o& *Ui"
exec sp_change_users_login 'update_one','newname','oldname' 3]'3{@{}H
go
#xmUND`@
5、检查备份集 *jYwcW"R{z
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' -&c@c@dC
6、修复数据库 q9OIw1xQr*
ALTER DATABASE [dvbbs] SET SINGLE_USER k@w&$M{tPF
GO E^g6,Y:i9
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK #\}hN~@F
GO X_h+\
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ALTER DATABASE [dvbbs] SET MULTI_USER YXvKDw'95
GO .}tL:^'~o
7、日志清除 HV}NT~
SET NOCOUNT ON Y !`H_Qo
DECLARE @LogicalFileName sysname, ]C!u~A\jq
@MaxMinutes INT, 1yhx)m;f
@NewSize INT E_++yK^=
USE tablename -- 要操作的数据库名 A#T;Gi
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ^C(AMT
@MaxMinutes = 10, -- Limit on time allowed to wrap log. bHp|>g
@NewSize = 1 -- 你想设定的日志文件的大小(M) t[<=QK
-- Setup / initialize oR+Fn}mG
DECLARE @OriginalSize int CTwP{[%Pk
SELECT @OriginalSize = size KT3[{lr
FROM sysfiles `]%{0 Rx
WHERE name = @LogicalFileName @y,p-##e
SELECT 'Original Size of ' + db_name() + ' LOG is ' + '!_o`t@
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ,yB-jk?
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' D!:Qy@Zw
FROM sysfiles bc+'n
WHERE name = @LogicalFileName hJ|z8Sy@1
CREATE TABLE DummyTrans TqWvHZX
(DummyColumn char (8000) not null) ag3T[}L
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DECLARE @Counter INT, PgVM>_nHk
@StartTime DATETIME, ar6Z?v$
@TruncLog VARCHAR(255) 3LEN~N}
SELECT @StartTime = GETDATE(), DU;]Q:r{
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' A)qOJ(OEz
DBCC SHRINKFILE (@LogicalFileName, @NewSize) '8dqJ`Gj
EXEC (@TruncLog) pPIH`Iq
-- Wrap the log if necessary. Va1|XQ<CL
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired I} j!
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) S`NH6?/uH
AND (@OriginalSize * 8 /1024) > @NewSize ~sM334sQ
BEGIN -- Outer loop. dZZHk
SELECT @Counter = 0 &B))3WFy
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) UPbG_ #"wZ
BEGIN -- update 2+|[e_
INSERT DummyTrans VALUES ('Fill Log') 6ds&n#n
DELETE DummyTrans V482V#BP
SELECT @Counter = @Counter + 1 jildiT[s
END 5bgx;z9
EXEC (@TruncLog) l!`m}$
END c0tv!PSw
SELECT 'Final Size of ' + db_name() + ' LOG is ' + uz%rWN`{
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + &)rmv
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 3 iY`kf
FROM sysfiles Z!*Wn`d-k
WHERE name = @LogicalFileName " I:j a7
DROP TABLE DummyTrans ^fRA$t
SET NOCOUNT OFF AR&u9Y)I
8、说明:更改某个表 ^.k}YSWut
exec sp_changeobjectowner 'tablename','dbo' GLEGyT?~
9、存储更改全部表 zhFGMF1
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch FQ );el'_V
@OldOwner as NVARCHAR(128), (Y-7B
@NewOwner as NVARCHAR(128) k+_pj k
AS uHy^ Bq
DECLARE @Name as NVARCHAR(128) !W8$-iq
DECLARE @Owner as NVARCHAR(128) dD#A.C,Rz
DECLARE @OwnerName as NVARCHAR(128) 3Y>!e#
DECLARE curObject CURSOR FOR lx%<oC+M
select 'Name' = name, d
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'Owner' = user_name(uid) *`|F?wF
from sysobjects XWK A0
where user_name(uid)=@OldOwner 1,Y-_e)
order by name n`}vcVL;
OPEN curObject kGCd!$fsk
FETCH NEXT FROM curObject INTO @Name, @Owner hMi`n6m
WHILE(@@FETCH_STATUS=0) ^ng?+X>mP
BEGIN Zsaz#z|xW
if @Owner=@OldOwner VNF@)!l
begin uZi]$/ic
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 75gE>:f
exec sp_changeobjectowner @OwnerName, @NewOwner Dk/;`sXV
end 7v#sr<
-- select @name,@NewOwner,@OldOwner BsRxD9r
FETCH NEXT FROM curObject INTO @Name, @Owner 'r3I/qg*m
END zxXm9zrLo
close curObject "`16-g97
deallocate curObject ]5B5J
GO ~fEgrF d
10、SQL SERVER中直接循环写入数据 5v8_ji#l[
declare @i int |_Z(}%
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set @i=1 MH1??vW
while @i<30 uTngDk
begin (J5E]NV
insert into test (userid) values(@i) =ejkE;
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set @i=@i+1 S$ dFz
end Q!MS_
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小记存储过程中经常用到的本周,本月,本年函数 YS%HZFY, "
Dateadd(wk,datediff(wk,0,getdate()),-1) _r&`[@m
Dateadd(wk,datediff(wk,0,getdate()),6) v 6Tz7
Dateadd(mm,datediff(mm,0,getdate()),0) !\2Xr{f
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) tyNT1F{
Dateadd(yy,datediff(yy,0,getdate()),0) mm'Pe4*
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) JuS#p5E #
上面的SQL代码只是一个时间段 u1(`^^Ml
Dateadd(wk,datediff(wk,0,getdate()),-1) y?;&(Tcbt8
Dateadd(wk,datediff(wk,0,getdate()),6) eA4@)6W P(
就是表示本周时间段. an=8['X
下面的SQL的条件部分,就是查询时间段在本周范围内的: ~[t%g9
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) b v~"_)C
而在存储过程中 P;{f+I|`
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) )mS
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) gm\P`~+o