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。 h7W%}6Cqkw
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一、基础 A*26'
1、说明:创建数据库 +VpE-X=T
CREATE DATABASE database-name d;jJe0pH
2、说明:删除数据库 }^Ua
drop database dbname <{z3p:\
3、说明:备份sql server Lugk`NUvF
--- 创建 备份数据的 device Eztz~oFo
USE master IIt^e#s&
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' "JUQ)> !?
--- 开始 备份 ]x(2}h^S
BACKUP DATABASE pubs TO testBack z:Zn.e*$b
4、说明:创建新表 * /Ry6Yu
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..)
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根据已有的表创建新表: !wR{Y[Yu
A:create table tab_new like tab_old (使用旧表创建新表) .L(j@I t
B:create table tab_new as select col1,col2... from tab_old definition only 18w^7!F?~u
5、说明:删除新表 g7}z
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drop table tabname SeJFZ0p
6、说明:增加一个列 ,,H$>r_;
Alter table tabname add column col type I }W-5%
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。 KutgW#+40
7、说明:添加主键: Alter table tabname add primary key(col) :
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说明:删除主键: Alter table tabname drop primary key(col) I9G*iu=U
8、说明:创建索引:create [unique] index idxname on tabname(col....) /&!d
删除索引:drop index idxname ZEyGqCf3
注:索引是不可更改的,想更改必须删除重新建。 R#Nd|f<
9、说明:创建视图:create view viewname as select statement oQjB&0k4
删除视图:drop view viewname &_^*rD~
10、说明:几个简单的基本的sql语句 @Jn:!8U0
选择:select * from table1 where 范围 w KMk|y>
插入:insert into table1(field1,field2) values(value1,value2) y[5P<:&s
删除:delete from table1 where 范围 Ccd7|L1
更新:update table1 set field1=value1 where 范围 vyx\N{
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Lv5
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排序:select * from table1 order by field1,field2 [desc] 0qd;'r<
总数:select count as totalcount from table1 $I6eHjYT
求和:select sum(field1) as sumvalue from table1 io33+/
平均:select avg(field1) as avgvalue from table1 GqD!W8+
最大:select max(field1) as maxvalue from table1 Lvj5<4h;
最小:select min(field1) as minvalue from table1 m<'xlF
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11、说明:几个高级查询运算词 6 r-n6#=
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A: UNION 运算符 |e[0Qo@
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。 xjbyI_D
B: EXCEPT 运算符 llG#nDe
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。 gWv+i/,
C: INTERSECT 运算符 [QqNsco)
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。 Q]g 4gj
注:使用运算词的几个查询结果行必须是一致的。 GxDF7
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12、说明:使用外连接 ?nSp?m;
A、left outer join: NUnc"@
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。 @)'@LF1Z
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 F)iGD~
B:right outer join:
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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。 >/`cmNmb
C:full outer join: bq&S?! =s
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。 DUliU8B}\
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二、提升 (cA|N0
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) L(n~@gq
法一:select * into b from a where 1<>1 Jx>B %vZ\
法二:select top 0 * into b from a pD6g+Taj
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ;I))gY-n
insert into b(a, b, c) select d,e,f from b;
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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) CU`Oc>;*T
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 dQ|Ht[s=
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. @N_H]6z4
4、说明:子查询(表名1:a 表名2:b) od's1'cR
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) x)wt.T?eL
5、说明:显示文章、提交人和最后回复时间 ~)8i5p;P/k
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b |Ge/|;.v`
6、说明:外连接查询(表名1:a 表名2:b) 3a)Q:#okD
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c R}6la.mQ
7、说明:在线视图查询(表名1:a ) Tocdh.H|
select * from (SELECT a,b,c FROM a) T where t.a > 1; "XsY~
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 1@z@
select * from table1 where time between time1 and time2 ow$l!8
select a,b,c, from table1 where a not between 数值1 and 数值2 ;AB ,:*
9、说明:in 的使用方法 rJQ|Oi&1i
select * from table1 where a [not] in ('值1','值2','值4','值6') K/d&c]
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ^W[`##,{Od
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 4-rI4A<
11、说明:四表联查问题: L{,7(C=
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 ..... x&/Syb
12、说明:日程安排提前五分钟提醒 GhQ`{iJM
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 kDP^[V
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13、说明:一条sql 语句搞定数据库分页 5{/Pn%5
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 e27CbA{_w
14、说明:前10条记录 3v>,c>b([
select top 10 * form table1 where 范围 `"":
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.) RkP|_Bf8)
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) $5CY<,f
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 m:Cx~
(select a from tableA ) except (select a from tableB) except (select a from tableC) WJ4UJdf'
17、说明:随机取出10条数据 @%G"i:HZ&
select top 10 * from tablename order by newid() ]JPPL4wAT
18、说明:随机选择记录 \lIHC{V\
select newid() UXB8sS*wQ?
19、说明:删除重复记录 JU \J
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) _"bvT?|
20、说明:列出数据库里所有的表名 $<%
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select name from sysobjects where type='U' -t'oW*kdL
21、说明:列出表里的所有的 vk+%#w
select name from syscolumns where id=object_id('TableName') ZjW| qb
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 !enz05VW6.
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type EjE`S_i=
显示结果: XTaWd0Y
type vender pcs RW[<e
电脑 A 1 \0T*msYQ
电脑 A 1 Xt*%"7yTp
光盘 B 2 f /i,Zw
光盘 A 2 +9rbQ?'
手机 B 3 6U9Fa=%>}
手机 C 3 X&oy.Roo
23、说明:初始化表table1 |8{iIvi/
TRUNCATE TABLE table1 FH(+7Lz4;
24、说明:选择从10到15的记录 /_\W*@ E
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc +1fOW4!5
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三、技巧 }M@Jrq+7
1、1=1,1=2的使用,在SQL语句组合时用的较多 HwMsP$`q
"where 1=1" 是表示选择全部 "where 1=2"全部不选, }4]x"DfIg
如: 'wV26Dm
if @strWhere !='' V="f)'S$
begin *LdH/C.LIf
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere \#7%%>p=O'
end Riuv@i^6K
else 6;XpLivP7
begin MJpTr5Vs
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ,,wx197XeD
end c;}n=7,>:L
我们可以直接写成 bO%ck-om!
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere UI|@5:J
2、收缩数据库 !-nm7Q
--重建索引 :Zo2@8@7
DBCC REINDEX 5MU@g*gj,C
DBCC INDEXDEFRAG *<QL[qyV
--收缩数据和日志 9sU,.T
DBCC SHRINKDB TsW6 w
DBCC SHRINKFILE &-Er n/[
3、压缩数据库 eG>Fn6G<g
dbcc shrinkdatabase(dbname) IVODR
4、转移数据库给新用户以已存在用户权限 Cs=i9.-A
exec sp_change_users_login 'update_one','newname','oldname' =C1Qo#QQ%
go ([o:_5/8I
5、检查备份集 ]=<@G.[=
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' vg1s5Yqk
6、修复数据库 _!1c.[\T
ALTER DATABASE [dvbbs] SET SINGLE_USER %~XJwy-
GO &scD)
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK BTtYlpN6
GO {j*+:Gj0V
ALTER DATABASE [dvbbs] SET MULTI_USER 9gayu<J
GO IFoN<<7/2$
7、日志清除 oioN0EuDk
SET NOCOUNT ON Ps4A
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DECLARE @LogicalFileName sysname, ` &7?+s
@MaxMinutes INT, *X5LyO3-gP
@NewSize INT |q)Q<%VS'
USE tablename -- 要操作的数据库名 A~SSu.L@
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Mn;CG'FA
@MaxMinutes = 10, -- Limit on time allowed to wrap log. c4W"CD;D
@NewSize = 1 -- 你想设定的日志文件的大小(M) vAxtNRS
-- Setup / initialize aKr4E3`
DECLARE @OriginalSize int [c )\?MWW
SELECT @OriginalSize = size m]pvJJ@
FROM sysfiles <QLj6#d7Y
WHERE name = @LogicalFileName )@M|YM1+
SELECT 'Original Size of ' + db_name() + ' LOG is ' + *9^k^h(r&4
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ,1h(k<-
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' c{ (%+
FROM sysfiles rn*VL(Yd(
WHERE name = @LogicalFileName <WkLwP3^
CREATE TABLE DummyTrans 4yy
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(DummyColumn char (8000) not null) :\We =oX
DECLARE @Counter INT, D)6|| z}
@StartTime DATETIME, 1H@F>}DP
@TruncLog VARCHAR(255) $R36`wk
SELECT @StartTime = GETDATE(), KJZY.7
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 5|z[%x~f
DBCC SHRINKFILE (@LogicalFileName, @NewSize) $7g(-W
EXEC (@TruncLog) ^@eCT}p{
-- Wrap the log if necessary. zxHfQ(
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired s#49pDN
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) PmTd+Gj$
AND (@OriginalSize * 8 /1024) > @NewSize -W vAmi
BEGIN -- Outer loop. |8ZAE%/d
SELECT @Counter = 0 =5F49
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) c~;.m<yrf
BEGIN -- update \LXNdE2B
INSERT DummyTrans VALUES ('Fill Log') H[U*'
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DELETE DummyTrans |REU7?B
SELECT @Counter = @Counter + 1 3E:<
END [-a/]
EXEC (@TruncLog) "E#%x{d
END !OemS7{
SELECT 'Final Size of ' + db_name() + ' LOG is ' + oWOZ0]H1
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Zwl?*t\D
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' Os+=}
FROM sysfiles 1-<Xi-=^{t
WHERE name = @LogicalFileName qILr+zH
DROP TABLE DummyTrans 5J3kQ;5Q?
SET NOCOUNT OFF '-{jn+,
8、说明:更改某个表 oaE3Aa
exec sp_changeobjectowner 'tablename','dbo' ]P^ +~
9、存储更改全部表 6Wp:W1E{`
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch =wc[r?7
@OldOwner as NVARCHAR(128), Hq8.O/Y"=
@NewOwner as NVARCHAR(128) G9Ezm*I;:
AS ST.W{:X
DECLARE @Name as NVARCHAR(128) qxh\umm+2
DECLARE @Owner as NVARCHAR(128) b2H6}s"=w
DECLARE @OwnerName as NVARCHAR(128) 9!h+LGs(,
DECLARE curObject CURSOR FOR ~.tu#Y?
select 'Name' = name, K*[wr@)u
'Owner' = user_name(uid) ;rbn/6
from sysobjects @,.H)\a4
where user_name(uid)=@OldOwner dno*Usx5d0
order by name ,B><la87
OPEN curObject Ho|n\7$
FETCH NEXT FROM curObject INTO @Name, @Owner uqH;1T;s
WHILE(@@FETCH_STATUS=0) un=)k;oh
BEGIN 6!N&,I
if @Owner=@OldOwner A}# Mrb
begin -B!pg7>'##
set @OwnerName = @OldOwner + '.' + rtrim(@Name) rKxk?}
exec sp_changeobjectowner @OwnerName, @NewOwner ,"v%
end 9X~^w_cdk
-- select @name,@NewOwner,@OldOwner 2(|V1]6D?
FETCH NEXT FROM curObject INTO @Name, @Owner !b=$FOC>
END ^&%?Q_]
close curObject iV=#'yY
deallocate curObject L3\{{QOA
GO n\4+xZr
10、SQL SERVER中直接循环写入数据 -TWo-iu^
declare @i int lQjq6Fl2
set @i=1 .b"e`Bw_=
while @i<30 ~@bKQ>Xw
begin j!/(9*\
insert into test (userid) values(@i) Qzv_|U
set @i=@i+1 +Oa1FvoEA
end 7Ll(,i<,C
小记存储过程中经常用到的本周,本月,本年函数 ?a}~yz#B(
Dateadd(wk,datediff(wk,0,getdate()),-1) :OM>z4mQ
Dateadd(wk,datediff(wk,0,getdate()),6) \I=:,cz*,
Dateadd(mm,datediff(mm,0,getdate()),0) + h&V;
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) fA^ O
Dateadd(yy,datediff(yy,0,getdate()),0) AJ /_l;
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) EUgs2Fsb3
上面的SQL代码只是一个时间段 VTdZ&%@
Dateadd(wk,datediff(wk,0,getdate()),-1) ?{V[bm
Dateadd(wk,datediff(wk,0,getdate()),6) |r%P.f:y{X
就是表示本周时间段. ~+Y;jAdU
下面的SQL的条件部分,就是查询时间段在本周范围内的: $- L)>"
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) s*@.qN
而在存储过程中 w;"'l]W
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) f &|SGD*
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) \l~h#1|%;s