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。 @$%.iQ7A;
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一、基础 Y 9st3
1、说明:创建数据库 vI48*&]wTf
CREATE DATABASE database-name g]BA/Dw
2、说明:删除数据库 ~xws5n}F
drop database dbname 3.ShAL
3、说明:备份sql server v5?ct?q
--- 创建 备份数据的 device P"@^BQ4
USE master TXs&*\
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' WqCj;Tj|
--- 开始 备份 N_+D#Z.g
BACKUP DATABASE pubs TO testBack CEzdH!nP
4、说明:创建新表 f^IB:e#j;
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Q+_z*
根据已有的表创建新表: !u4eI0?R?
A:create table tab_new like tab_old (使用旧表创建新表) t.bM]QU!1
B:create table tab_new as select col1,col2... from tab_old definition only "W9z>ezp
5、说明:删除新表 ^![7X'!;pt
drop table tabname ~~t>;
6、说明:增加一个列 ]xJ.OUJy
Alter table tabname add column col type /,$V/q+
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。 %* gg6Q
7、说明:添加主键: Alter table tabname add primary key(col) |'x"+x
说明:删除主键: Alter table tabname drop primary key(col) {Dy,u%W?
8、说明:创建索引:create [unique] index idxname on tabname(col....)
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删除索引:drop index idxname }%42Ty
注:索引是不可更改的,想更改必须删除重新建。 *#?9@0b@
9、说明:创建视图:create view viewname as select statement EW`WFBjj
删除视图:drop view viewname -0NkAQrg
10、说明:几个简单的基本的sql语句 [I<J6=
选择:select * from table1 where 范围 wCj)@3F
插入:insert into table1(field1,field2) values(value1,value2) hwi_=-SL
删除:delete from table1 where 范围 mW,b#'hy
更新:update table1 set field1=value1 where 范围 Aq>?G+
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! /h]ru SI
排序:select * from table1 order by field1,field2 [desc] iorQ/(
总数:select count as totalcount from table1 <KoOJMx(
求和:select sum(field1) as sumvalue from table1 [W3sveqj&
平均:select avg(field1) as avgvalue from table1 e$rPXRf
最大:select max(field1) as maxvalue from table1 {QOy'
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最小:select min(field1) as minvalue from table1 A#i[Us|
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11、说明:几个高级查询运算词 ztp2j%'
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A: UNION 运算符 K(Tej W#
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 2)QZYgfh
B: EXCEPT 运算符 .O&YdUo
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 uy<b5.!-
C: INTERSECT 运算符 #hXvGon$?
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&3pK>f
注:使用运算词的几个查询结果行必须是一致的。 t/3qD7L
12、说明:使用外连接 )vuIO(8F#
A、left outer join: 5EECr
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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。 UDgX
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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 @zLyG#kHY
B:right outer join: (rBYE[@,
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。 E9@Sc>e
C:full outer join: \uJ+~db=
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。 Fp]ErDan
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二、提升 Cyo:Da
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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) :C={Z}t/F
法一:select * into b from a where 1<>1 B9c
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法二:select top 0 * into b from a {yd(n_PqY
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) qc';<
insert into b(a, b, c) select d,e,f from b; <P]%{msGH
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) O+[s4]
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 4#ikdjB;
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. vCOtED*<
4、说明:子查询(表名1:a 表名2:b) 2gEF$?+q?
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) K&T.~2'>
5、说明:显示文章、提交人和最后回复时间 nm%7 e!{m
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Re*~C:
6、说明:外连接查询(表名1:a 表名2:b) 4 DV,f2:R4
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c /`y^z"!
7、说明:在线视图查询(表名1:a ) t7,$u-
select * from (SELECT a,b,c FROM a) T where t.a > 1; Lnq CHe
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 )FfS7 C\.
select * from table1 where time between time1 and time2 =gZA9@]W2
select a,b,c, from table1 where a not between 数值1 and 数值2 W"A3$/nq^
9、说明:in 的使用方法 6X4r2Vq
select * from table1 where a [not] in ('值1','值2','值4','值6') z 8#{=e
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Ip *8R]W
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Ev3,p`zS._
11、说明:四表联查问题: 7m:TY>{
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 ..... {7_C|z:'p&
12、说明:日程安排提前五分钟提醒 &78lep
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 -uhVw_qq#
13、说明:一条sql 语句搞定数据库分页 ^7=h%{>=
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 %D%
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14、说明:前10条记录 +NeoGnj
select top 10 * form table1 where 范围 $)6M@S
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) {L7+lz
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) o/=61K8D
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 Qx_N,1>S
(select a from tableA ) except (select a from tableB) except (select a from tableC) ogJ';i/o
17、说明:随机取出10条数据 "x
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select top 10 * from tablename order by newid() *,=8x\Shp
18、说明:随机选择记录 9j5-/
select newid() 80Q%c( i
19、说明:删除重复记录 K=pG,[ChA
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) N-45LS@
20、说明:列出数据库里所有的表名 "}oo`+]Cq
select name from sysobjects where type='U' 53^3..E|
21、说明:列出表里的所有的 7)FYAk$@
select name from syscolumns where id=object_id('TableName') joNV4v"=`
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。 8;,|z%rS"
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 X `F>kp1
显示结果: 1Cw$^jd
type vender pcs Q"3gvIyc
电脑 A 1 HLL=.: P
电脑 A 1 =CjWPZShV
光盘 B 2 ~w.y9)",
光盘 A 2 8~BLTZ
手机 B 3 lc]cs D
手机 C 3 @iBmOt>3
23、说明:初始化表table1 yDj'')LOQg
TRUNCATE TABLE table1 Kp;a(D
24、说明:选择从10到15的记录 SQMtR2
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc %CUwD
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三、技巧 $P2*qpqy
1、1=1,1=2的使用,在SQL语句组合时用的较多 b S' dXP
"where 1=1" 是表示选择全部 "where 1=2"全部不选, $0+&xJVn
如: Mf7
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if @strWhere !='' b+L !p.:
begin j'lC]}kH
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere BbPRPkV
end [e{D
else sN) xNz
begin Fr2F&NN`D
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' YHxQb$v)
end :lK8i{o
我们可以直接写成 f>&*%[fw
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere *<}R=X.
2、收缩数据库 46B'Ec
--重建索引 "_=t1UE
DBCC REINDEX bXqTc2>=
DBCC INDEXDEFRAG ,?+uQXfXR
--收缩数据和日志 +I}!)$/
DBCC SHRINKDB $Yw~v36`t/
DBCC SHRINKFILE 8>xd
3、压缩数据库 ,8cVv->u/
dbcc shrinkdatabase(dbname) Y@ vC!C
4、转移数据库给新用户以已存在用户权限 aN!,\D
exec sp_change_users_login 'update_one','newname','oldname' ,kl``w|1M
go 0oqOX
5、检查备份集 vJsg6oH
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 7$8DMBqq
6、修复数据库 ZkNet>9
ALTER DATABASE [dvbbs] SET SINGLE_USER =-qYp0sVP
GO U r8JG&,
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK k?1e+ \
GO z.OJ1vY7
ALTER DATABASE [dvbbs] SET MULTI_USER ?JW/Stua
GO 0n={Mb
7、日志清除 90ov[|MkM
SET NOCOUNT ON r"t,/@`n
DECLARE @LogicalFileName sysname, bw!*=<
@MaxMinutes INT, `(6cRT`Wp
@NewSize INT ~B7<Yg
USE tablename -- 要操作的数据库名 VZ7E#z+nM#
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 0_=^#r4Mu
@MaxMinutes = 10, -- Limit on time allowed to wrap log. }1Q>A 5e
@NewSize = 1 -- 你想设定的日志文件的大小(M) 4H{$zMq8
-- Setup / initialize ;q#Pl!*5
DECLARE @OriginalSize int GgE
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SELECT @OriginalSize = size j(M.7Z7^
FROM sysfiles Bw9O)++
WHERE name = @LogicalFileName c4s,T"H
SELECT 'Original Size of ' + db_name() + ' LOG is ' + -U\s.FI.AR
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + $+,kibk*R
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' R3.8Dr0f
FROM sysfiles 5,\|XQA5!
WHERE name = @LogicalFileName PWO5R]
CREATE TABLE DummyTrans Q9Go}}n
(DummyColumn char (8000) not null) m6Qm }""
DECLARE @Counter INT, e2pFX?
@StartTime DATETIME, 2(P<TP._E
@TruncLog VARCHAR(255) 1O1MB&5%
SELECT @StartTime = GETDATE(),
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Owv}lJ
DBCC SHRINKFILE (@LogicalFileName, @NewSize) n;QFy5HB8
EXEC (@TruncLog) _:Jma
-- Wrap the log if necessary. [ fs.D /
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 8~O0P=
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) B3I0H6O
AND (@OriginalSize * 8 /1024) > @NewSize O5:[]vIn
BEGIN -- Outer loop. A+z}z@K
SELECT @Counter = 0 O:8Ne*L`D
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000))
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BEGIN -- update tJm1Q#||
INSERT DummyTrans VALUES ('Fill Log') ):n'B` f}z
DELETE DummyTrans Dv4 H^
SELECT @Counter = @Counter + 1 gf^y3F[\
END c(!pcB8
EXEC (@TruncLog) b=SCyGxlZ5
END q2;CvoF
SELECT 'Final Size of ' + db_name() + ' LOG is ' + .k%/JF91n
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 6LqF*$+$`
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' Hr \vu`p$
FROM sysfiles kPO+M~+n
WHERE name = @LogicalFileName w8#ji 1gX
DROP TABLE DummyTrans '<O.J(N~4!
SET NOCOUNT OFF 162Dj$
8、说明:更改某个表 UlPGB2B
exec sp_changeobjectowner 'tablename','dbo' 3PkU>+.6
9、存储更改全部表 ?.c:k;j
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 6w_TL<S
@OldOwner as NVARCHAR(128), |;"(C# B
@NewOwner as NVARCHAR(128) ?uW}
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AS ~b%dBn]n>
DECLARE @Name as NVARCHAR(128) Oe;1f#`5
DECLARE @Owner as NVARCHAR(128) Fz5eCe\B
DECLARE @OwnerName as NVARCHAR(128) 7dOpJjv?)
DECLARE curObject CURSOR FOR g\*2w
@
select 'Name' = name, P~PM $e
'Owner' = user_name(uid) f9O_M1=|lo
from sysobjects d^0-|sx
where user_name(uid)=@OldOwner E#cu}zi
order by name |\)Y,~;P
OPEN curObject a|k*A&5u2
FETCH NEXT FROM curObject INTO @Name, @Owner u_b6u@r7
WHILE(@@FETCH_STATUS=0) shiw;.vR{B
BEGIN 'CRjd~L
if @Owner=@OldOwner -67!u;
begin 3@1$y`SN
set @OwnerName = @OldOwner + '.' + rtrim(@Name) X<f4X"y
exec sp_changeobjectowner @OwnerName, @NewOwner Ty*+?#`
end n} ]gAX
-- select @name,@NewOwner,@OldOwner hb>uHUb&
FETCH NEXT FROM curObject INTO @Name, @Owner m]}EVa_I`/
END 8<J3Xe
close curObject PK&X |
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deallocate curObject +KOhDtLMG
GO X9rao n
10、SQL SERVER中直接循环写入数据 KXBTJ&
declare @i int _<?z-K_;I
set @i=1 T^ #1T$
while @i<30 +Q"XwxL<6
begin XMaw:Fgr
insert into test (userid) values(@i) z$VVt?K
set @i=@i+1 wp@6RJ
end kc2
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小记存储过程中经常用到的本周,本月,本年函数 $MM[`^~
Dateadd(wk,datediff(wk,0,getdate()),-1) N5tFEV'G
Dateadd(wk,datediff(wk,0,getdate()),6) ]jR-<l8I-
Dateadd(mm,datediff(mm,0,getdate()),0) Yfy";C7X
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) QHtN_Q_F
Dateadd(yy,datediff(yy,0,getdate()),0) v7D0E[)~
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) VS65SxHA
上面的SQL代码只是一个时间段 }Q-Tw,j
Dateadd(wk,datediff(wk,0,getdate()),-1) c57`mOe/b
Dateadd(wk,datediff(wk,0,getdate()),6) xX8c>p
就是表示本周时间段. v2YU2-X[
下面的SQL的条件部分,就是查询时间段在本周范围内的: SUL\|z`5
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) oq(W|
而在存储过程中 @scSW5+
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ?gjkgCbC#
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) >VG*La'c