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。 6CCZda@
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一、基础 WReYF+Uen
1、说明:创建数据库 65 NWX8f}
CREATE DATABASE database-name J*/$ywI
2、说明:删除数据库 ;I[.
drop database dbname zjzqKdy}F
3、说明:备份sql server @:I\\S@bN
--- 创建 备份数据的 device 4+ykE:
USE master [<,0A]m
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' X*(gT1"t
--- 开始 备份 `>$gy/N
BACKUP DATABASE pubs TO testBack %9fa98>
4、说明:创建新表 !x+MVJ]
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) `W6:=H
根据已有的表创建新表: Be'?#Qe
A:create table tab_new like tab_old (使用旧表创建新表) ,!xz*o+#@
B:create table tab_new as select col1,col2... from tab_old definition only d91I
5、说明:删除新表 Sz^TGF
drop table tabname &:IfhS
6、说明:增加一个列 jqV)V> M.
Alter table tabname add column col type aU,0gvI(}
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。 zS#f%{
7、说明:添加主键: Alter table tabname add primary key(col) Tq_1wX'\
说明:删除主键: Alter table tabname drop primary key(col) H!Fr("6}
8、说明:创建索引:create [unique] index idxname on tabname(col....) $@XPL~4
删除索引:drop index idxname 3^uL`ETm@
注:索引是不可更改的,想更改必须删除重新建。 ;2+FgOj
9、说明:创建视图:create view viewname as select statement 9CgXc5
删除视图:drop view viewname r! cNc
10、说明:几个简单的基本的sql语句 vy>];!Cu
选择:select * from table1 where 范围 30wYc &H
插入:insert into table1(field1,field2) values(value1,value2) o;Hd W
删除:delete from table1 where 范围 h'z+8X_t
更新:update table1 set field1=value1 where 范围 OLhWkN,qA
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! T<w*dX7F0K
排序:select * from table1 order by field1,field2 [desc] cN0~;!{i
总数:select count as totalcount from table1 XY&]T'A
求和:select sum(field1) as sumvalue from table1 g^Ugl=f,
平均:select avg(field1) as avgvalue from table1 /S-/SF:>g
最大:select max(field1) as maxvalue from table1 n#/U@qVgc
最小:select min(field1) as minvalue from table1 v]UU&Jq8U
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11、说明:几个高级查询运算词 Iqe=#hUFe!
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A: UNION 运算符 3}.mp}K5
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 0`aHwt/F
B: EXCEPT 运算符 IeqWR4Y
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 "RR./e)h
C: INTERSECT 运算符 V{/)RZ/
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 I\F=s-VVY
注:使用运算词的几个查询结果行必须是一致的。 #L).BM
12、说明:使用外连接 L~SrI{aYPf
A、left outer join: FcJ.)U
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 ,Yiq$Z{qQ
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 U>3%!83kF
B:right outer join: $A5B{2
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 soFvrl^Ql+
C:full outer join: @eAGN|C5
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 Q}k_#w
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二、提升 6w:g77SH)%
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) -Lz1#S k]A
法一:select * into b from a where 1<>1 Z]1z*dv
法二:select top 0 * into b from a A1=$kzw{UH
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) [xp~@5r'
insert into b(a, b, c) select d,e,f from b; <*b]JY V@
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) iPtm@f,bI
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 CU7iva
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. *cb
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4、说明:子查询(表名1:a 表名2:b) (<AM+|
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) { 8|Z}?I
5、说明:显示文章、提交人和最后回复时间 _Oaso >
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ZQJw2LA gO
6、说明:外连接查询(表名1:a 表名2:b) !pFKC)
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 4IGQ,RTB
7、说明:在线视图查询(表名1:a ) |n-a\
select * from (SELECT a,b,c FROM a) T where t.a > 1; 7!` C TE
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 D{Jc+Q$
select * from table1 where time between time1 and time2 t"!8
select a,b,c, from table1 where a not between 数值1 and 数值2 3qV>TE]6,
9、说明:in 的使用方法 [4+a 1/^
select * from table1 where a [not] in ('值1','值2','值4','值6') xYzcV%-Pm
10、说明:两张关联表,删除主表中已经在副表中没有的信息 t0AqGrn
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) $HR(|{piZ
11、说明:四表联查问题: (0+ GLI8
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... OA8b_k~
12、说明:日程安排提前五分钟提醒 F~uA-g
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 %l]rQjV-
13、说明:一条sql 语句搞定数据库分页 `)gkkZ$)j
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 W0r5D9k
14、说明:前10条记录 n<"a+TTU
select top 10 * form table1 where 范围 !A ydhe
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.) 'piF_5(@
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) B2Awdw3=g
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 tr67ofld|
(select a from tableA ) except (select a from tableB) except (select a from tableC) /i]=ndAk
17、说明:随机取出10条数据 F6neG~Y
select top 10 * from tablename order by newid() {H7$uiq3:B
18、说明:随机选择记录 KH 6n3 \=
select newid() 7HR%rO?'
19、说明:删除重复记录 7=M'n;!Mh
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) A)`fD
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20、说明:列出数据库里所有的表名 ED =BZR
select name from sysobjects where type='U' 6u]OXPA|
21、说明:列出表里的所有的 80l3.z,:
select name from syscolumns where id=object_id('TableName') vCH v
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 1H2u,{O
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type KI?1(L
显示结果: :8GxcqvCWq
type vender pcs A5>gLhl7
电脑 A 1 SUFaHHk@/b
电脑 A 1 m} FCe
光盘 B 2 O.40^u~
光盘 A 2 9Av- ;!]
手机 B 3 ~?8x0
手机 C 3 4 *2>R8SX~
23、说明:初始化表table1 dQ2i{A"BKz
TRUNCATE TABLE table1 S r#fyr
24、说明:选择从10到15的记录 iJp!ROI
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc t BXsWY{
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三、技巧
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1、1=1,1=2的使用,在SQL语句组合时用的较多 Zv7$epDUz
"where 1=1" 是表示选择全部 "where 1=2"全部不选, TYLl_nGr
如: _$jJpy
if @strWhere !='' !E.lyz
begin [8J}da }
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere YI(OrR;V
end H f mMf^c
else BrH`:Dw
begin kpMM%"=V
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' }mS0{rxD4
end 1X:whS5S
我们可以直接写成 ]e3}9.
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere u C8T!z
2、收缩数据库 0 Ukl#6
--重建索引 (j 8,n<o
DBCC REINDEX Q8/0Cb/
DBCC INDEXDEFRAG D@vvy6>~s
--收缩数据和日志 ';L^mxh
DBCC SHRINKDB 8J(zWV7 r
DBCC SHRINKFILE l$_+WC*wp
3、压缩数据库 l?<z1Acd&
dbcc shrinkdatabase(dbname) z{M,2
4、转移数据库给新用户以已存在用户权限 arH\QPaka'
exec sp_change_users_login 'update_one','newname','oldname' 1R~WY'Ed
go N %/DN
5、检查备份集 V$F.`O!hfi
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' *gpD4c7A\
6、修复数据库 ,ce^"yG
ALTER DATABASE [dvbbs] SET SINGLE_USER MldL"*HW:
GO \iE9&3Ie
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK tS\NO@E_Jh
GO xr-`i
ALTER DATABASE [dvbbs] SET MULTI_USER _CwQ}n*
GO %+W
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7、日志清除 1kw4'#J8
SET NOCOUNT ON %IXW|mi
DECLARE @LogicalFileName sysname, %L|bF"K5;
@MaxMinutes INT, WM l ^XZO
@NewSize INT /Gv$1t^a
USE tablename -- 要操作的数据库名 HnY"6gTNK
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ^3s&90
@MaxMinutes = 10, -- Limit on time allowed to wrap log. `Q^Sm`R
@NewSize = 1 -- 你想设定的日志文件的大小(M) KIl.?_61O
-- Setup / initialize m-FDCiN>
DECLARE @OriginalSize int &B,& *Lp
SELECT @OriginalSize = size .E8p-R5)V>
FROM sysfiles EuA<{%i
WHERE name = @LogicalFileName 7?WBzo!!L
SELECT 'Original Size of ' + db_name() + ' LOG is ' + w=>mG-
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + +rO<'H:umJ
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 4'[ V'c\
FROM sysfiles uiEA=*axp
WHERE name = @LogicalFileName /<pQ!'/G
CREATE TABLE DummyTrans l5nDt$Ex
(DummyColumn char (8000) not null) 05LQh
DECLARE @Counter INT, [)0 k}
@StartTime DATETIME, +7OT`e
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@TruncLog VARCHAR(255) exKmK!FT
SELECT @StartTime = GETDATE(), 4'b]2Mn3
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' v!9Imf
DBCC SHRINKFILE (@LogicalFileName, @NewSize) "fJ|DE&@<i
EXEC (@TruncLog) &+iW:
-- Wrap the log if necessary. D)Rf
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 0lh6b3tdP
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) yC*B OJS
AND (@OriginalSize * 8 /1024) > @NewSize 1)r _h(
BEGIN -- Outer loop. ^TuEp$Z=
SELECT @Counter = 0 cyeDZ)
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 0\^2HjsJ
BEGIN -- update ]Wm ?<7H
INSERT DummyTrans VALUES ('Fill Log') &nw~gSe
DELETE DummyTrans Ou,_l
SELECT @Counter = @Counter + 1 ZTC1t_
END z6r/
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EXEC (@TruncLog) ,PxQ[CGg
END w o9f99
SELECT 'Final Size of ' + db_name() + ' LOG is ' + qyfxT Q5
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + {S(T1ua
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' $s!meg@s
FROM sysfiles uL AXN
WHERE name = @LogicalFileName "
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DROP TABLE DummyTrans ,]qX_`qF
SET NOCOUNT OFF .g?,:$`0D?
8、说明:更改某个表 !_!b\
exec sp_changeobjectowner 'tablename','dbo' C>VZf,JE1
9、存储更改全部表 C
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch o@;_(knb
@OldOwner as NVARCHAR(128), Y &+/[[
@NewOwner as NVARCHAR(128) *lO+^\HXD
AS TBT*j&!L
DECLARE @Name as NVARCHAR(128) WfO$q^'?DP
DECLARE @Owner as NVARCHAR(128) CxQ,yd;>
DECLARE @OwnerName as NVARCHAR(128) Khd ,|pM
DECLARE curObject CURSOR FOR Pk_{{Z(1o
select 'Name' = name, (.+n1)L?
'Owner' = user_name(uid) YcZ4y@6"
from sysobjects MX\-)e#
where user_name(uid)=@OldOwner W/Q%%)J
order by name Ls*=mh~IY
OPEN curObject 2=+ ,jX{
FETCH NEXT FROM curObject INTO @Name, @Owner EIm\!'R]
WHILE(@@FETCH_STATUS=0) R?SHXJ%'
BEGIN cLP@0`^H
if @Owner=@OldOwner %n,bPa>T
begin 1R9/AP
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 1 to<at-NN
exec sp_changeobjectowner @OwnerName, @NewOwner ibw;BU
end EBLoRW=8ld
-- select @name,@NewOwner,@OldOwner ;mlIWn
FETCH NEXT FROM curObject INTO @Name, @Owner ]~ UkD*Ct
END _S1uJ~j;E
close curObject RVx<2,['
deallocate curObject k<qH<<r*
GO j-|0&X1C
10、SQL SERVER中直接循环写入数据 zSCPp6
declare @i int "PtH
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set @i=1 *^_!W'T{j
while @i<30 \M@8# k|
begin Ka{Zoi]
insert into test (userid) values(@i) 5Oq ;V:7
set @i=@i+1 Vrh],xK7
end MEUqQ4/Gl
小记存储过程中经常用到的本周,本月,本年函数 CU_06A|}
Dateadd(wk,datediff(wk,0,getdate()),-1) (B#|3o
Dateadd(wk,datediff(wk,0,getdate()),6) cf!R
Dateadd(mm,datediff(mm,0,getdate()),0) jXZNr
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) --sb ;QG
Dateadd(yy,datediff(yy,0,getdate()),0) _AHVMsz@
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) k#[s)Ja?s
上面的SQL代码只是一个时间段 !o!04_
Dateadd(wk,datediff(wk,0,getdate()),-1) gs>cx]>
Dateadd(wk,datediff(wk,0,getdate()),6) ~!kbB4`WK
就是表示本周时间段. !6C d.fpWL
下面的SQL的条件部分,就是查询时间段在本周范围内的: VRt*!v<")
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) cqp#1oM4M
而在存储过程中 ] plC
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) RoZV6U~
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 8{u01\0}