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。 n
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一、基础 g*c\'~f;
1、说明:创建数据库 /uz5V/i0
CREATE DATABASE database-name ?N?pe}
2、说明:删除数据库 pr,1Wp0l
drop database dbname %iS]+Sa.K
3、说明:备份sql server (*WZsfk>/<
--- 创建 备份数据的 device @[kM1:G-F{
USE master -hR\Y2?
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' q.b4m 'J
--- 开始 备份 8*PAgPj a
BACKUP DATABASE pubs TO testBack Hi"
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4、说明:创建新表 U9[A(
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) K2MNaB
根据已有的表创建新表: tKsM}+fq
A:create table tab_new like tab_old (使用旧表创建新表) W#\};P
B:create table tab_new as select col1,col2... from tab_old definition only "XsY~
5、说明:删除新表 N3c)ce7[
drop table tabname NEou2y+}
6、说明:增加一个列 "/Q(UV<d
Alter table tabname add column col type 5a|m}2IX
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。 [,$mpJCI
7、说明:添加主键: Alter table tabname add primary key(col) k8wi-z[dV
说明:删除主键: Alter table tabname drop primary key(col) _N f[HP
8、说明:创建索引:create [unique] index idxname on tabname(col....) aq \TO?
删除索引:drop index idxname @wgGnb)
注:索引是不可更改的,想更改必须删除重新建。 AG\852`1m
9、说明:创建视图:create view viewname as select statement }ZVv
删除视图:drop view viewname BOQV X&g%
10、说明:几个简单的基本的sql语句 si.a]k/f
选择:select * from table1 where 范围 ~(L +4]
插入:insert into table1(field1,field2) values(value1,value2) 9x^
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删除:delete from table1 where 范围 m:Cx~
更新:update table1 set field1=value1 where 范围
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 9.#R?YP$
排序:select * from table1 order by field1,field2 [desc] >8;%F<o2
总数:select count as totalcount from table1 d4h(F,K7V
求和:select sum(field1) as sumvalue from table1 C{,] 1X6g
平均:select avg(field1) as avgvalue from table1 zYF&Dv/u/
最大:select max(field1) as maxvalue from table1 )0d".Q|v4
最小:select min(field1) as minvalue from table1 +pViHOJu&V
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11、说明:几个高级查询运算词 #I~dv{RX
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A: UNION 运算符 7:q-NzE\6
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。 Yn2^nT=8
B: EXCEPT 运算符 +Qb/:xQu
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。 'p+QFT>Ca
C: INTERSECT 运算符 ;p!hd}C
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。 :BxYaAVt^
注:使用运算词的几个查询结果行必须是一致的。 &0Zk3D4
12、说明:使用外连接 ^K8a#-
A、left outer join: N_[ Q.HD"
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。 w/W?/1P>q
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 =V]i?31[
B:right outer join: Q09~vFBg
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。 Sz@?%PnU|
C:full outer join: 2#M:JgWV
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。 }gRLW2&mR>
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二、提升 QjN3j*@
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) g@f/OsR76
法一:select * into b from a where 1<>1 N%E2BJ?
法二:select top 0 * into b from a (MiOrzT
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) }(}vlL
insert into b(a, b, c) select d,e,f from b; s\FNKWQ
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) T\CQ
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 @Hdg-f>y]
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. > 0)`uJ
4、说明:子查询(表名1:a 表名2:b) Z@O
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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) 6v)eM=
5、说明:显示文章、提交人和最后回复时间 `|?$; )
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b @7 HBXP
6、说明:外连接查询(表名1:a 表名2:b) \JC(pn
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c :Zo2@8@7
7、说明:在线视图查询(表名1:a ) 5MU@g*gj,C
select * from (SELECT a,b,c FROM a) T where t.a > 1; @$}\S
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 r9*H-V$
select * from table1 where time between time1 and time2 l<_mag/j9o
select a,b,c, from table1 where a not between 数值1 and 数值2 '6J$X-
9、说明:in 的使用方法 k r^#B^
select * from table1 where a [not] in ('值1','值2','值4','值6') n8aiGnd=v
10、说明:两张关联表,删除主表中已经在副表中没有的信息 1U9N8{xg9
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) HTpd~W/\
11、说明:四表联查问题: 48rYs}
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 ..... }mZ*f y0t
12、说明:日程安排提前五分钟提醒 >(KUYX?p
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 4GA-dtyV&
13、说明:一条sql 语句搞定数据库分页 Xb
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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 t1s@Ub5);I
14、说明:前10条记录 ZaindX{.1
select top 10 * form table1 where 范围 G)|HFcE
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.) vGp@YABM
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) tzJtd
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 =H?5fT^
(select a from tableA ) except (select a from tableB) except (select a from tableC) _tJURk%
17、说明:随机取出10条数据 qqred>K
select top 10 * from tablename order by newid() qZ1PC>
18、说明:随机选择记录 d0E5 ;3tQ
select newid() aJ;R8(*;\
19、说明:删除重复记录 Nx
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) O4mWsr
20、说明:列出数据库里所有的表名 vAxtNRS
select name from sysobjects where type='U' aKr4E3`
21、说明:列出表里的所有的 o;/F=Zp
select name from syscolumns where id=object_id('TableName') :8T@96]P
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。 G=Bj1ss.
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 (7!(e
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显示结果: vG:,oB}
type vender pcs {'aqOlw3<j
电脑 A 1 vjS7nR"T
电脑 A 1 g&5VorGx
光盘 B 2 tvCTC ey
光盘 A 2 8#-}3~l[
手机 B 3 `P*j~ZLlXN
手机 C 3 WLFzLW=PD
23、说明:初始化表table1 XaSl6CH
TRUNCATE TABLE table1 NO1]JpR
24、说明:选择从10到15的记录 vbJMgdHFR
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc h0}-1kVT^
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三、技巧 t2<(by!
1、1=1,1=2的使用,在SQL语句组合时用的较多 J3^Ir [
"where 1=1" 是表示选择全部 "where 1=2"全部不选, b~echOj
如: +Q&@2 oY"
if @strWhere !='' u:?RdB}B_@
begin X)5O@"4 ?
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere mz'8
end n&&y\?n
else ?id^v 7d
begin ]TN}`]
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' .1M>KRSr,
end uS.a9
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我们可以直接写成 'iK*#b8l
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere :D-vE7
2、收缩数据库 u?/]"4
--重建索引 %&GQ]pmcY
DBCC REINDEX N`fY%"5U>
DBCC INDEXDEFRAG Fd'L:A~
--收缩数据和日志 X/"H+l
DBCC SHRINKDB W0hLh<Go
DBCC SHRINKFILE cH ?]uu(
3、压缩数据库 <3OV
dbcc shrinkdatabase(dbname) |[ofc!/
4、转移数据库给新用户以已存在用户权限 $nWmoe)
exec sp_change_users_login 'update_one','newname','oldname' =z.AQe+
go 2Ta F7Jn
5、检查备份集 =wc[r?7
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Hq8.O/Y"=
6、修复数据库 G9Ezm*I;:
ALTER DATABASE [dvbbs] SET SINGLE_USER #xB%v
GO GV/FK{v5
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK w"J(sVy4
GO ~coG8r"o
ALTER DATABASE [dvbbs] SET MULTI_USER ?c*d
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GO ~o$=(EC
7、日志清除 Sj+#yct -
SET NOCOUNT ON cFQa~
DECLARE @LogicalFileName sysname, lN"rhZ
@MaxMinutes INT, I}x*AM 7+
@NewSize INT B$j,: ^
USE tablename -- 要操作的数据库名 }o.ZCACYg
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 c:5BQr
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. ]T`qPIf;yJ
@NewSize = 1 -- 你想设定的日志文件的大小(M) 7ac3N
-- Setup / initialize /8R1$7
DECLARE @OriginalSize int 9G9lSj5>
SELECT @OriginalSize = size '@bA_F(
FROM sysfiles zvWQ&?&o2
WHERE name = @LogicalFileName 38^_(N
SELECT 'Original Size of ' + db_name() + ' LOG is ' + #'oKkrl
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + [g_@<?zg
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ]2'~e,"O
FROM sysfiles 4B]a8
WHERE name = @LogicalFileName Zup?nP2GkT
CREATE TABLE DummyTrans -Zh+5;8g
(DummyColumn char (8000) not null) Qfi5fp=f
DECLARE @Counter INT, lQjq6Fl2
@StartTime DATETIME, `{":*V
@TruncLog VARCHAR(255) <j'#mUzd
SELECT @StartTime = GETDATE(), `P~RG.HO
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' (;3jmdJhK
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 1GxYuTZ{
EXEC (@TruncLog) b04~z&Xv
-- Wrap the log if necessary. B~IOM
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired wv$=0zF
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) E}u\{uY
AND (@OriginalSize * 8 /1024) > @NewSize B#}RMFIj
BEGIN -- Outer loop. `JCC-\9T_
SELECT @Counter = 0 rO~D{)Nu
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 2ou?:5i
BEGIN -- update 60Z)AQs;+J
INSERT DummyTrans VALUES ('Fill Log') :H{8j}"
DELETE DummyTrans $) $sApB
SELECT @Counter = @Counter + 1 U?>cm`DBP
END qeYr= %)c
EXEC (@TruncLog) *`W82V
END ZmDr$iU~
SELECT 'Final Size of ' + db_name() + ' LOG is ' + f!yxS?j3
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + zob-z=='
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' w_ m
FROM sysfiles V SxLBwXf
WHERE name = @LogicalFileName )yk
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DROP TABLE DummyTrans 2#^[`sFPO
SET NOCOUNT OFF P\R3/g
8、说明:更改某个表 f]4gDmn^
exec sp_changeobjectowner 'tablename','dbo' E =E
9、存储更改全部表 /T@lHxX
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch d=pq+
@OldOwner as NVARCHAR(128), sC
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@NewOwner as NVARCHAR(128) T&%>/7I>
AS -T>`PJpJuL
DECLARE @Name as NVARCHAR(128) K67x.P Z
DECLARE @Owner as NVARCHAR(128) Onl:eG;@
DECLARE @OwnerName as NVARCHAR(128) mP-+];gg
DECLARE curObject CURSOR FOR sfLBi~*j
select 'Name' = name, 8c#*T%Vf
'Owner' = user_name(uid)
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from sysobjects V}*b^<2o5
where user_name(uid)=@OldOwner K;Ktx>Z/
order by name _Z%C{~,7)x
OPEN curObject 8LL);"$
FETCH NEXT FROM curObject INTO @Name, @Owner wRKGJ
WHILE(@@FETCH_STATUS=0) AjpQb~\
BEGIN 1g@kHq
if @Owner=@OldOwner P*}Oi7Z
begin 1/z1~:Il
set @OwnerName = @OldOwner + '.' + rtrim(@Name) +MEWAW[}^
exec sp_changeobjectowner @OwnerName, @NewOwner SE\`JGA[
end D_{J:Hb
-- select @name,@NewOwner,@OldOwner `CV a`%
FETCH NEXT FROM curObject INTO @Name, @Owner C1_NGOvT
END QwiC2}/
close curObject C$_H)I
deallocate curObject h1"#DnK7
GO 'ySWf,Q^
10、SQL SERVER中直接循环写入数据 iL(E`_I<
declare @i int e&:fzO<~I
set @i=1 +XQ6KG&
while @i<30 NXV%j},>
begin X'5te0v`3
insert into test (userid) values(@i) Eb*DP_
set @i=@i+1 R_lNC]b0
end -V\33cA
小记存储过程中经常用到的本周,本月,本年函数 eI@O9<.&
Dateadd(wk,datediff(wk,0,getdate()),-1) c;Li~FLR
Dateadd(wk,datediff(wk,0,getdate()),6) (C!fIRY
Dateadd(mm,datediff(mm,0,getdate()),0) kAqk~.
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) K3jno+U&
Dateadd(yy,datediff(yy,0,getdate()),0) e}kG1C8
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 6>l-jTM
上面的SQL代码只是一个时间段 ),n?"
Dateadd(wk,datediff(wk,0,getdate()),-1) Yy&0b(m U
Dateadd(wk,datediff(wk,0,getdate()),6) 2$jY_{B+x
就是表示本周时间段. ukN#>e+L1
下面的SQL的条件部分,就是查询时间段在本周范围内的: <1"6`24
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) dM
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而在存储过程中 6ik6JL$AI
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1)
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 7Kn=[2J5k'