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。 +6jGU'}[
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一、基础 Kg>B$fBx)
1、说明:创建数据库 MnF|'t
CREATE DATABASE database-name 9e>2kd
2、说明:删除数据库 O|=?!|`o
drop database dbname @d|Sv1d%
3、说明:备份sql server uE (5q!/
--- 创建 备份数据的 device
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USE master Q$]1juqg
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' GBRiU&D
--- 开始 备份 t g-(e=S4P
BACKUP DATABASE pubs TO testBack DBcR1c&<H
4、说明:创建新表 +4T.3Njjn
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) F}meKc?a
根据已有的表创建新表: Vn{;8hZ:a
A:create table tab_new like tab_old (使用旧表创建新表) ^OIo
B:create table tab_new as select col1,col2... from tab_old definition only ^q/^.Gf
5、说明:删除新表 &1^~G0Rh\
drop table tabname OGJrwl
6、说明:增加一个列 +MaEet
Alter table tabname add column col type qk3~]</
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。 .-&
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7、说明:添加主键: Alter table tabname add primary key(col) Et-|[ eL
说明:删除主键: Alter table tabname drop primary key(col) ps,Kj3^T<
8、说明:创建索引:create [unique] index idxname on tabname(col....) zZRLFfz<9
删除索引:drop index idxname tB`"gC~
注:索引是不可更改的,想更改必须删除重新建。 f-[.^/
9、说明:创建视图:create view viewname as select statement <b_K*]Z
删除视图:drop view viewname sg}<()
10、说明:几个简单的基本的sql语句 iiJT%Zq`#
选择:select * from table1 where 范围 y $uq`FW
插入:insert into table1(field1,field2) values(value1,value2) iWr
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删除:delete from table1 where 范围 PZZPx<?N
更新:update table1 set field1=value1 where 范围 z@\mn
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! vShB26b
排序:select * from table1 order by field1,field2 [desc] Z"w}`&TC$^
总数:select count as totalcount from table1 4h--x~ @
求和:select sum(field1) as sumvalue from table1 04v
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平均:select avg(field1) as avgvalue from table1 VZ`YbY
最大:select max(field1) as maxvalue from table1 tS3&&t
最小:select min(field1) as minvalue from table1 AT3HHQD
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11、说明:几个高级查询运算词 t4:/qy
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A: UNION 运算符 <^{(?*
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。 Nr,I`x\N
B: EXCEPT 运算符 KV&6v`K/N
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。 F 8sOc&L
C: INTERSECT 运算符 $J)`Ru6.
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。 r]D>p&4
注:使用运算词的几个查询结果行必须是一致的。 }u0&> k|y
12、说明:使用外连接 fiSX( 9
A、left outer join: <GQ=PrT|/
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。 gjnEN1T22
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 'IIa,']H
B:right outer join: $[MAm)c:]{
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 KOXG=P0
C:full outer join: &K[~Ab_
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 o::9M_;
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二、提升 09Eg ti.
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) lcReRcjm
法一:select * into b from a where 1<>1 ]=xX_
法二:select top 0 * into b from a &vN!>bR
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) A(`Mwh+
insert into b(a, b, c) select d,e,f from b; |+sAqx1IF
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) p}gA8o
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 T5T[$%]6
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. T<Zi67QC@
4、说明:子查询(表名1:a 表名2:b) 5i'?oXL
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) L5KcI
5、说明:显示文章、提交人和最后回复时间 0
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select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 9X33{
6、说明:外连接查询(表名1:a 表名2:b) MuzQz.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 7AGUi+!ICl
7、说明:在线视图查询(表名1:a ) wEI?
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select * from (SELECT a,b,c FROM a) T where t.a > 1; ".#h$
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 ~Cyn w(
select * from table1 where time between time1 and time2 e F}KOOfC
select a,b,c, from table1 where a not between 数值1 and 数值2
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9、说明:in 的使用方法 UM21Cfqex
select * from table1 where a [not] in ('值1','值2','值4','值6') kqo4
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10、说明:两张关联表,删除主表中已经在副表中没有的信息 :2vuc!Pu
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) i7 YUyU
11、说明:四表联查问题: OR|Jc+LT
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 ..... b~)2`l
12、说明:日程安排提前五分钟提醒 -T+'3</T
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 a7u*d`3X=
13、说明:一条sql 语句搞定数据库分页 z}$.A9yn
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 [GI2%uA0
14、说明:前10条记录 !a!4^zqp
select top 10 * form table1 where 范围 {dE(.Z?]!#
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) RK$(
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) pTTM(Hrx
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 $X\2h+ Os
(select a from tableA ) except (select a from tableB) except (select a from tableC) :h3U^
17、说明:随机取出10条数据 {o*$|4q4
select top 10 * from tablename order by newid() 3X ',L*f
18、说明:随机选择记录
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select newid() <KCyXU*
19、说明:删除重复记录 ubVZEsoW?
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) K g.O2F77
20、说明:列出数据库里所有的表名 i 2uSPV!Tf
select name from sysobjects where type='U' P;'ZdZ(SLu
21、说明:列出表里的所有的 u:l<NWF^
select name from syscolumns where id=object_id('TableName') TPKD'@:x
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。 (./Iq#@S
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 8+Gwv
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显示结果: [fvjvN`
type vender pcs r5(efTgAd+
电脑 A 1 s+&0Z3+
电脑 A 1 N$:-q'hX
光盘 B 2 JlRNJ#h>
光盘 A 2 swJQwY
手机 B 3 Y;g\ @j
手机 C 3 =kK%,Mr
23、说明:初始化表table1 _E6N*ORV
TRUNCATE TABLE table1 n8T'}d+mm
24、说明:选择从10到15的记录 Clap3E|a
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Ja/
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三、技巧 }:J-o
1、1=1,1=2的使用,在SQL语句组合时用的较多 "K+EZ%~<
"where 1=1" 是表示选择全部 "where 1=2"全部不选, H<?s[MH[
如: d:_;
if @strWhere !='' #@1(
begin ;/+U.I%z
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ,i;#e
end ^%LyT!y
else Y5"HKW^
begin # M!1W5#
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' R)isWw4
end 6P,uy;PJ
我们可以直接写成 N:+d=G`x
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere V 7ZGT
2、收缩数据库 JZ:yPvJ
--重建索引 GWWaH+F[h
DBCC REINDEX >XM]UdP
DBCC INDEXDEFRAG :Y9/} b{
--收缩数据和日志 *_}0vd
DBCC SHRINKDB _bgv +/
DBCC SHRINKFILE YGc:84S
3、压缩数据库 PQh s^D
dbcc shrinkdatabase(dbname) !<~cjgdx
4、转移数据库给新用户以已存在用户权限 {5d 5Y%&
exec sp_change_users_login 'update_one','newname','oldname' F>X<=YO0
go pe3;pRh'
5、检查备份集 fl2XI=[v4
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Y
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6、修复数据库 \W=
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ALTER DATABASE [dvbbs] SET SINGLE_USER
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GO N&Ho$,2s
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK )t\aB_ =
GO K"X"2c1o
ALTER DATABASE [dvbbs] SET MULTI_USER %9S0!h\
GO 5)h fI7{d
7、日志清除 o?a3hD
SET NOCOUNT ON "QiLu=Rq
DECLARE @LogicalFileName sysname, YB2gxZ
@MaxMinutes INT, x#R6Ez7
@NewSize INT ?0+g.,9
USE tablename -- 要操作的数据库名 G\V*j$}!
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 &,{YfAxQ`
@MaxMinutes = 10, -- Limit on time allowed to wrap log. Jo~fri([%Q
@NewSize = 1 -- 你想设定的日志文件的大小(M) 0!$y]Gr
-- Setup / initialize 3 5L0CM
DECLARE @OriginalSize int n%4/@M
SELECT @OriginalSize = size (-&d0a9N
FROM sysfiles +PKsiUJ|
WHERE name = @LogicalFileName Y}<%~z#.4
SELECT 'Original Size of ' + db_name() + ' LOG is ' + MPw?HpM
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + S3E5^n\\
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' $7i[7S4
FROM sysfiles 3Z&!zSK^
WHERE name = @LogicalFileName FC+h
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CREATE TABLE DummyTrans D&~%w!
(DummyColumn char (8000) not null) Vry_X2
DECLARE @Counter INT, IvI..#EzG
@StartTime DATETIME, \/V#,O
@TruncLog VARCHAR(255) X:g#&e_
SELECT @StartTime = GETDATE(), 'V&Uh]>
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' $b53~
DBCC SHRINKFILE (@LogicalFileName, @NewSize) r`h".=oD
EXEC (@TruncLog) ~<s^HP2U{
-- Wrap the log if necessary. "h7Dye
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ;ny 9q
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) j F/S2Ty2
AND (@OriginalSize * 8 /1024) > @NewSize 8]R{5RGy
BEGIN -- Outer loop. n5^57[(
SELECT @Counter = 0 wEJzLFCn
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) v=cQ`nou
BEGIN -- update Ude?[6
INSERT DummyTrans VALUES ('Fill Log') p?4[nS-,
DELETE DummyTrans CXyb8z4/+
SELECT @Counter = @Counter + 1 +"=ydF.9
END A=p'`]Yld
EXEC (@TruncLog) oVPr`]
END 4neO$^i8J
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ylQj2B,CB
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + SO[ u4b_"h
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' [K'gvLt1
FROM sysfiles k6RVP:V
WHERE name = @LogicalFileName
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DROP TABLE DummyTrans ^w<aS
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SET NOCOUNT OFF L/]
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8、说明:更改某个表 yBIX<P)vE'
exec sp_changeobjectowner 'tablename','dbo' yTZo4c"
9、存储更改全部表 cF8 X
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch zR]!g|;f
@OldOwner as NVARCHAR(128), aW{5m@p{"
@NewOwner as NVARCHAR(128) x-%RRm<V
AS ftl?x'P%
DECLARE @Name as NVARCHAR(128) 9n;6zVV%`
DECLARE @Owner as NVARCHAR(128) 5$cjCjY
DECLARE @OwnerName as NVARCHAR(128) w-LENdw
DECLARE curObject CURSOR FOR X?n=UebO^
select 'Name' = name, : T7(sf*!*
'Owner' = user_name(uid) VO=Ibu&X
from sysobjects PJe_qP
where user_name(uid)=@OldOwner L
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order by name 8UqH"^9.Q7
OPEN curObject xSSEDfq
FETCH NEXT FROM curObject INTO @Name, @Owner tpO'<b
WHILE(@@FETCH_STATUS=0) bcpsjUiy#
BEGIN 5I^;v;F
if @Owner=@OldOwner 6o(IL-0]c
begin NRp
set @OwnerName = @OldOwner + '.' + rtrim(@Name) hwJ>IQ1
exec sp_changeobjectowner @OwnerName, @NewOwner NMf#0Nz-
end g=@d!]Z~[
-- select @name,@NewOwner,@OldOwner ^+CHp(X
FETCH NEXT FROM curObject INTO @Name, @Owner @|Yn~PwKs
END ka8Y+Gs
close curObject voN~f>
deallocate curObject LyWY\K a
GO [wnp]'+!
10、SQL SERVER中直接循环写入数据 #9!7-!4pW
declare @i int : MjDcI~
set @i=1 {+E]c:{
while @i<30 JTm'fo[
begin Y|Gp\
insert into test (userid) values(@i) qq)}GK8K&
set @i=@i+1 HK~SD:d
end W{tZX^|
小记存储过程中经常用到的本周,本月,本年函数 u;c
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Dateadd(wk,datediff(wk,0,getdate()),-1) 9q_{_%G%
Dateadd(wk,datediff(wk,0,getdate()),6) =W:=}ODD
Dateadd(mm,datediff(mm,0,getdate()),0) dr: x0>
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Xo/H+[;X
Dateadd(yy,datediff(yy,0,getdate()),0) Rb&9!z
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) gBcs
上面的SQL代码只是一个时间段 ; teM^zyI
Dateadd(wk,datediff(wk,0,getdate()),-1) ]S[?tn
Dateadd(wk,datediff(wk,0,getdate()),6) 0F/[GZ<k
就是表示本周时间段. 3]mprX'
下面的SQL的条件部分,就是查询时间段在本周范围内的: iRlZWgj4^
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ~"SQwE|
而在存储过程中 09jE7g @X}
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) }l[e@6r F
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) U$& '> %#