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。 HL34pmc
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一、基础 @WfX{485
1、说明:创建数据库 1GI/gc\
CREATE DATABASE database-name k.("<)
2、说明:删除数据库 *9I/h~I
drop database dbname <{kr5<
3、说明:备份sql server kZJ.G
--- 创建 备份数据的 device )ND%MYJSq
USE master D0HLU
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' P8=!/L2?
--- 开始 备份 l4smAT
BACKUP DATABASE pubs TO testBack ExJexjOWI^
4、说明:创建新表 :qL1jnR^
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) L-QzC<[F/
根据已有的表创建新表: ;!H|0sv
A:create table tab_new like tab_old (使用旧表创建新表) b$k|D)_|
B:create table tab_new as select col1,col2... from tab_old definition only Cp[
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5、说明:删除新表 j&
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drop table tabname 6|AD]/t^K
6、说明:增加一个列 YH^h?s
Alter table tabname add column col type mH\eJ
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 "JJEF2e@Z
7、说明:添加主键: Alter table tabname add primary key(col) @EV*QC2l;Y
说明:删除主键: Alter table tabname drop primary key(col) eSlZAdK
8、说明:创建索引:create [unique] index idxname on tabname(col....) S=.7$PY
删除索引:drop index idxname :$gR
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注:索引是不可更改的,想更改必须删除重新建。 Re^~8q[
9、说明:创建视图:create view viewname as select statement f9FLtdh
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删除视图:drop view viewname 8dYPn+`
10、说明:几个简单的基本的sql语句 w\QMA3
选择:select * from table1 where 范围 y1@*)|
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插入:insert into table1(field1,field2) values(value1,value2) oGXndfd"
删除:delete from table1 where 范围 oP 4z>
更新:update table1 set field1=value1 where 范围 ">D7wX,.>
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! WjVj@oC
排序:select * from table1 order by field1,field2 [desc] mf\eg`'4?
总数:select count as totalcount from table1 GfMCHs
求和:select sum(field1) as sumvalue from table1 TqN4OkCm/
平均:select avg(field1) as avgvalue from table1 vk]vtjf&%
最大:select max(field1) as maxvalue from table1 z-X_O32
最小:select min(field1) as minvalue from table1 e
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11、说明:几个高级查询运算词 {'e%Hx
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A: UNION 运算符 <4m@WG
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。 z6+D=<
B: EXCEPT 运算符 a][QY1E@?
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。 '|JBA.s|
C: INTERSECT 运算符 jJOs`'~Q\
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。 !0k'fYCa
注:使用运算词的几个查询结果行必须是一致的。 +'f+0T\)
12、说明:使用外连接 ~qP_1()
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A、left outer join: SV}C]<
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。 %zCV>D
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 jQIb :\0#
B:right outer join: ?5e]^H}
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。 ,9@JBV%_
C:full outer join: K,'v{wSr
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。 OqcM3#
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二、提升 zXRq) ;s
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) -4IHs=`;I
法一:select * into b from a where 1<>1 /suW{8A(E
法二:select top 0 * into b from a 2S^:fm}
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) rrL
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insert into b(a, b, c) select d,e,f from b; 8\H*Z2yF+
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) 9KgGK cy%
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ccPTJ/%$
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. A)j',jE&1
4、说明:子查询(表名1:a 表名2:b) xS>d$)rIj
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) 2uln)]
5、说明:显示文章、提交人和最后回复时间 4,)EG1
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b *`g'*R
6、说明:外连接查询(表名1:a 表名2:b) !um~P
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c p6Ie ?Gg
7、说明:在线视图查询(表名1:a ) , A@uSfC(
select * from (SELECT a,b,c FROM a) T where t.a > 1; ]QbT%0
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 R5KOai!
select * from table1 where time between time1 and time2 "xK#%eJjWd
select a,b,c, from table1 where a not between 数值1 and 数值2 N9}27T+4
9、说明:in 的使用方法 rUL_=>3
select * from table1 where a [not] in ('值1','值2','值4','值6') AIU=56+I\
10、说明:两张关联表,删除主表中已经在副表中没有的信息 :kb2v1{\
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) xxS>O%
11、说明:四表联查问题: Pn| ;VCh
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... :{Mr~Co*
12、说明:日程安排提前五分钟提醒 Q 2mTu[tx
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 7XU$O$C
13、说明:一条sql 语句搞定数据库分页 b$W~w*O
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 %&[=%zc
14、说明:前10条记录 #PJHwvr
select top 10 * form table1 where 范围 "z6xS;
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.) |3{"ANmm'
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) WNmG'hlA
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 \a7caT{
(select a from tableA ) except (select a from tableB) except (select a from tableC) B}U:c]
17、说明:随机取出10条数据 +$;*" o
select top 10 * from tablename order by newid() 2.>aL
18、说明:随机选择记录 M8{J
select newid() {IgLH`@
19、说明:删除重复记录 yRyUOTK
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ]I<w;.z
20、说明:列出数据库里所有的表名 u"s@eN
select name from sysobjects where type='U' 92 oUQ EK
21、说明:列出表里的所有的 mNk@WY_F
select name from syscolumns where id=object_id('TableName') # X`t~Y'
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。 $3'xb/3|
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type W_bp~Wu
显示结果: GnFm*L
type vender pcs pg9feIW1
电脑 A 1 s,;7m
电脑 A 1 \0,8?S
光盘 B 2 E3"j7y[S
光盘 A 2 ][TA7pDPV
手机 B 3 +
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手机 C 3 vXLGdv::
23、说明:初始化表table1 Mc@_[q!xY?
TRUNCATE TABLE table1 6F8TiR&
24、说明:选择从10到15的记录 vi;yT.
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc _X]\#^UiO2
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三、技巧 X@pcL{T!
1、1=1,1=2的使用,在SQL语句组合时用的较多 jb83Y>
"where 1=1" 是表示选择全部 "where 1=2"全部不选, n3"
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如: UpSa7F:Uw
if @strWhere !='' 'Y22HVUX
begin [R(d Cq>
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere dh-?_|"
end S[5OTwa8L
else W1
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begin vtw97G
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ecMpU8}rR
end Ie7S'.Lmq
我们可以直接写成 q${+I(b,
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere n3_|#1Qu
2、收缩数据库 %{B4M#~
--重建索引 >uP1k.z'I
DBCC REINDEX ufB9\yl{~
DBCC INDEXDEFRAG cMoBYk
--收缩数据和日志 W_bA.zT{
DBCC SHRINKDB XES$V15
DBCC SHRINKFILE qNX+!Y}y
3、压缩数据库 qoAJcr2uN
dbcc shrinkdatabase(dbname) U]PsL3:
4、转移数据库给新用户以已存在用户权限 RH^;M-'
exec sp_change_users_login 'update_one','newname','oldname' WiqkC#N
go -?L3"rxAP
5、检查备份集 #:E^($v
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' x }.&?m
6、修复数据库 =6d'/D#J
ALTER DATABASE [dvbbs] SET SINGLE_USER Zfc{}ius
GO T?KM}<$(O
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK },%,v2}
GO V( =3K"j
ALTER DATABASE [dvbbs] SET MULTI_USER R,+"^:}
GO 'NN3XyD
7、日志清除 J?/NJ-F
SET NOCOUNT ON nkkUby9
DECLARE @LogicalFileName sysname, c?}{>ig/)
@MaxMinutes INT, i;<K)5Z
@NewSize INT 1Gw_S?$7
USE tablename -- 要操作的数据库名 M!Ywjvw*)3
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 \=j|ju3
@MaxMinutes = 10, -- Limit on time allowed to wrap log. #&Fd16ov
@NewSize = 1 -- 你想设定的日志文件的大小(M) T~naAP
-- Setup / initialize Z|BOuB^
DECLARE @OriginalSize int 9Idgib&
SELECT @OriginalSize = size 5|g#>sx>`q
FROM sysfiles hY/i)T{
WHERE name = @LogicalFileName F>
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + *fp4u_:`
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + tN_~zP
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' "u3 N9
FROM sysfiles M5`wfF,j
WHERE name = @LogicalFileName iUk#0 I
CREATE TABLE DummyTrans 7!A3PDAe
(DummyColumn char (8000) not null) Q5c13g2(c
DECLARE @Counter INT, X=[`+=
@StartTime DATETIME, k8w:8*y'.
@TruncLog VARCHAR(255) _Kv;hR>
SELECT @StartTime = GETDATE(), IFkU8EK&B
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' oRHWb_$"
DBCC SHRINKFILE (@LogicalFileName, @NewSize) c HUj6'neO
EXEC (@TruncLog) Tl
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-- Wrap the log if necessary. N#8$pE
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired eo<=Q|nI&
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) GC)xQZU)s
AND (@OriginalSize * 8 /1024) > @NewSize P`y 0FKS
BEGIN -- Outer loop. I{7Hz{
SELECT @Counter = 0 `r+`vJ$
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ]64?S0p1c!
BEGIN -- update Q@-
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INSERT DummyTrans VALUES ('Fill Log') EoOwu-{
DELETE DummyTrans ;|.IUXEgcF
SELECT @Counter = @Counter + 1 yG:Pg MrB
END "FXT8Qxg
EXEC (@TruncLog) '_%`0p1
END k7=mxXF
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 3M[5_OK
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ePY69!pO5e
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ol@LLT_m
FROM sysfiles TN.&FDqC9
WHERE name = @LogicalFileName RQW<Sp~
DROP TABLE DummyTrans YA@OA$`E
SET NOCOUNT OFF 2@f?yh0
8、说明:更改某个表 $jN,]N~
exec sp_changeobjectowner 'tablename','dbo' F17nWvF
9、存储更改全部表 0[!38
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ZZU"Q7`^
@OldOwner as NVARCHAR(128), '
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@NewOwner as NVARCHAR(128) gro@+^DmT
AS $-lP"m@}
DECLARE @Name as NVARCHAR(128) f/]g@/`
DECLARE @Owner as NVARCHAR(128) +"D*0gYD
DECLARE @OwnerName as NVARCHAR(128) |^t8ct?x~
DECLARE curObject CURSOR FOR T0lbMp
select 'Name' = name, Q);^gV
'Owner' = user_name(uid) /Avl&Rd
from sysobjects E{E%nXR)
where user_name(uid)=@OldOwner :\,3=suWq
order by name X-J<gI(Y
OPEN curObject A!p70km2
FETCH NEXT FROM curObject INTO @Name, @Owner Y?V>%eBu
WHILE(@@FETCH_STATUS=0) ]F1ZeAh5
BEGIN S<DS|qOo
if @Owner=@OldOwner >TwL&la
begin v1~`76^
set @OwnerName = @OldOwner + '.' + rtrim(@Name) Oxr?y8C~
exec sp_changeobjectowner @OwnerName, @NewOwner )Tj\ym-Vl
end r?wE ;gH
-- select @name,@NewOwner,@OldOwner -,}ppTG
FETCH NEXT FROM curObject INTO @Name, @Owner M\jTeB"Z
END 2Ls
close curObject 5:~BGK&{Y
deallocate curObject c!=^C/5Ee
GO &HYs^|ydrr
10、SQL SERVER中直接循环写入数据 L
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declare @i int Wf:I
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set @i=1 O)9{qU:[b
while @i<30 kV3Zt@+
begin /WE1afe_R
insert into test (userid) values(@i)
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set @i=@i+1 3bPF+(`J
end A+bU{oLr
小记存储过程中经常用到的本周,本月,本年函数 < e7
Dateadd(wk,datediff(wk,0,getdate()),-1) [";<YR7iRN
Dateadd(wk,datediff(wk,0,getdate()),6) $.-\2;U
Dateadd(mm,datediff(mm,0,getdate()),0) 1U< g
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) "+:~#&r
Dateadd(yy,datediff(yy,0,getdate()),0) cQldBc
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 7cMSJM(]G
上面的SQL代码只是一个时间段 PK|"+I0
Dateadd(wk,datediff(wk,0,getdate()),-1) Ae 3:"
Dateadd(wk,datediff(wk,0,getdate()),6) xk$U+8K
就是表示本周时间段. \t
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下面的SQL的条件部分,就是查询时间段在本周范围内的: H}B%OFI \+
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) [_?dp aTt
而在存储过程中 q/HwcX+[b
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) mo-
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) iLD:}yK