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。 Xj(>.E{~H
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一、基础 R@&?i=gk
1、说明:创建数据库 GajI\_o
CREATE DATABASE database-name "(N-h\7Ex9
2、说明:删除数据库 D"'#one
drop database dbname Rn8#0%/Q
3、说明:备份sql server 7F~xq#Wi#
--- 创建 备份数据的 device j ~.u>4
USE master jWhD5k@v
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' g{]e j
--- 开始 备份 sE}sE=\
BACKUP DATABASE pubs TO testBack ^&HI+M
4、说明:创建新表 h ;jsH!
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) I'P!,Y/>
根据已有的表创建新表: $:P[v+Uy
A:create table tab_new like tab_old (使用旧表创建新表) u>1v~3,r#
B:create table tab_new as select col1,col2... from tab_old definition only (a,6a
5、说明:删除新表 0oQ/J:
drop table tabname f}A^]6MO:
6、说明:增加一个列 _4O[[~
Alter table tabname add column col type %$^$'6\77
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。 >[hrJn[
7、说明:添加主键: Alter table tabname add primary key(col) g*^wF?t'T
说明:删除主键: Alter table tabname drop primary key(col) uz8nRS s
8、说明:创建索引:create [unique] index idxname on tabname(col....) '&+Z ,
删除索引:drop index idxname ga,A'Z
注:索引是不可更改的,想更改必须删除重新建。 $*g{[&L|6
9、说明:创建视图:create view viewname as select statement ^g\h]RD}
删除视图:drop view viewname -)<JBs>
10、说明:几个简单的基本的sql语句 JW2W>6Dgv[
选择:select * from table1 where 范围 .ZM]%[4
插入:insert into table1(field1,field2) values(value1,value2) U24V55ZnI
删除:delete from table1 where 范围 f7K8m|
更新:update table1 set field1=value1 where 范围 omr:C8T>
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! -B",&yTV
排序:select * from table1 order by field1,field2 [desc] 2zwuvgiZ
总数:select count as totalcount from table1 XNy:0C
求和:select sum(field1) as sumvalue from table1 MuN[U17FB
平均:select avg(field1) as avgvalue from table1 +h9`I/R
最大:select max(field1) as maxvalue from table1 !P+~c0DF
最小:select min(field1) as minvalue from table1 O'Vh{JHf
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11、说明:几个高级查询运算词 *'s&/vEy
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A: UNION 运算符 65 NWX8f}
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 J*/$ywI
B: EXCEPT 运算符 E\W;:p,{A
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。 VNr!|bp5
C: INTERSECT 运算符 4c~*hMry
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。 zaQ$ Ht
注:使用运算词的几个查询结果行必须是一致的。 &IxxDvP3k
12、说明:使用外连接 G;87in ,}
A、left outer join: ~y( ,EO
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。 `Nc`xO?
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 9*"[pt+tA
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。 T
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C:full outer join: @DRfNJ}
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。 )WzGy~p8K
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二、提升 jqV)V> M.
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 0q-0zXlSL
法一:select * into b from a where 1<>1 ZK W@pW]U
法二:select top 0 * into b from a _gis+f/8h
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 3(>(lk
insert into b(a, b, c) select d,e,f from b; `kI?Af*;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) BHIZHp
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 17?NR\Q
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 7]R6
4、说明:子查询(表名1:a 表名2:b) btJ,dpir
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) |s)VjS4@
5、说明:显示文章、提交人和最后回复时间 R;5QD`
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ?Yynd
6、说明:外连接查询(表名1:a 表名2:b) /r #b
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 7R%
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7、说明:在线视图查询(表名1:a ) $sB48LJuU'
select * from (SELECT a,b,c FROM a) T where t.a > 1; eA;j/&qH
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 iPR!JX
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select * from table1 where time between time1 and time2 zzDNWPzsA
select a,b,c, from table1 where a not between 数值1 and 数值2 i'[n`|c<
9、说明:in 的使用方法 HPv&vdr3
select * from table1 where a [not] in ('值1','值2','值4','值6') [J[ysW})W
10、说明:两张关联表,删除主表中已经在副表中没有的信息 9u-M! $
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) lyMJW}T+>
11、说明:四表联查问题: .2 N_?
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 ..... [M,27
12、说明:日程安排提前五分钟提醒 w yuJSB
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5
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13、说明:一条sql 语句搞定数据库分页
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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 81%qM7v9H
14、说明:前10条记录 WHdqO8
select top 10 * form table1 where 范围 j};pv 2
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.) , 4h!"c
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 8VBkI Ygb
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 v)v{QNQp^
(select a from tableA ) except (select a from tableB) except (select a from tableC) a!SR"3 k
17、说明:随机取出10条数据 %BT)oH}
select top 10 * from tablename order by newid() QBN=l\m+
18、说明:随机选择记录 0e7O#-
select newid() soFvrl^Ql+
19、说明:删除重复记录 @eAGN|C5
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) Q}k_#w
20、说明:列出数据库里所有的表名 7k[`]:*o
select name from sysobjects where type='U' dd
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21、说明:列出表里的所有的 +w_MSj#P
select name from syscolumns where id=object_id('TableName') J"a2
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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。 8H$@Xts
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type kOlI?wc
显示结果: P5ESrZ@f
type vender pcs @ B}c4,
电脑 A 1 [|m>vY!
电脑 A 1 &})4?5
光盘 B 2 _mI:Lr#dT
光盘 A 2 Y`[HjS,
手机 B 3 (<AM+|
手机 C 3 { 8|Z}?I
23、说明:初始化表table1 _Oaso >
TRUNCATE TABLE table1 ZQJw2LA gO
24、说明:选择从10到15的记录 KY(l<pm
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc [W8iM7D
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三、技巧 #7cf 8y
1、1=1,1=2的使用,在SQL语句组合时用的较多 M7cI$=G
"where 1=1" 是表示选择全部 "where 1=2"全部不选, '6Z/-V4k
如: !@]h@MC$7
if @strWhere !='' K_w0+oY a
begin *6\`A!C
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere =":V
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end =."WvBKg
else z?b(|f\!
begin ADwwiq#E
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' p1`'1`.3
end Rp4BU"&sU
我们可以直接写成 f@x( ,p
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere E}CqVuU$
2、收缩数据库 (fLbg,
--重建索引 =>9.@`.
DBCC REINDEX NiJ?no
DBCC INDEXDEFRAG ;MdK3c
--收缩数据和日志 q}7Df!<|
DBCC SHRINKDB e4NX\tCpw
DBCC SHRINKFILE j{Qbzczy,
3、压缩数据库 }1^tK(Am
dbcc shrinkdatabase(dbname) ?6l,
4、转移数据库给新用户以已存在用户权限 3vvFF]D5k
exec sp_change_users_login 'update_one','newname','oldname' _`Yvfz3
go #dn%KMo2r
5、检查备份集 $BO}D
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' EF7|%N
6、修复数据库 fAA@ziKg
ALTER DATABASE [dvbbs] SET SINGLE_USER ss M9t
GO 3\U,Kg
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ?U.&7yY
GO Bbe/w#Z
ALTER DATABASE [dvbbs] SET MULTI_USER N4GIb 6
GO uzn))/"
7、日志清除 /EAQ.vxI
SET NOCOUNT ON l8n[8AT1
DECLARE @LogicalFileName sysname, ]qP}\+:
@MaxMinutes INT, ?RjKP3P
@NewSize INT ~ @"Qm;}
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USE tablename -- 要操作的数据库名 Ul~}@^m]4}
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Ivgwm6M
@MaxMinutes = 10, -- Limit on time allowed to wrap log. V44sNi
@NewSize = 1 -- 你想设定的日志文件的大小(M) J Wyoh|
-- Setup / initialize
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DECLARE @OriginalSize int Zv7$epDUz
SELECT @OriginalSize = size TYLl_nGr
FROM sysfiles T;pn -
WHERE name = @LogicalFileName snk{u/0Xm
SELECT 'Original Size of ' + db_name() + ' LOG is ' + KX`nHu;
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 7!QXh;u
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ~>-;(YU"t
FROM sysfiles #p9z#kin
WHERE name = @LogicalFileName MH~qfH>K
CREATE TABLE DummyTrans :@4>}k*
(DummyColumn char (8000) not null) r3bvuq,6$
DECLARE @Counter INT, >A@D;vx
@StartTime DATETIME, p-03V"^&
@TruncLog VARCHAR(255) bJMcI8`
SELECT @StartTime = GETDATE(), ST[1'T+L
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' $4~}_phi
DBCC SHRINKFILE (@LogicalFileName, @NewSize) a_fW{;}[
EXEC (@TruncLog) LyPBFo[?
-- Wrap the log if necessary. ?Dp^dR
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired s$y#Ufz
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) /v ;Kb|e
AND (@OriginalSize * 8 /1024) > @NewSize a0W\?
BEGIN -- Outer loop. arH\QPaka'
SELECT @Counter = 0 kp>Z /kt
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 36Y[7m=
BEGIN -- update I z=w2\r
INSERT DummyTrans VALUES ('Fill Log') B+H9c~3$
DELETE DummyTrans rls#gw
SELECT @Counter = @Counter + 1 /WgW e
END T|iF/p]F
EXEC (@TruncLog) -v+^x`HR
END `j"G=%e3.
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 5 9J$SE
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + umn~hb5O
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' )PATz
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FROM sysfiles U=#ylQ
WHERE name = @LogicalFileName Z1lF[d,f;
DROP TABLE DummyTrans U$JIF/MO_
SET NOCOUNT OFF WsDe0F
8、说明:更改某个表 R3!vS+5rR
exec sp_changeobjectowner 'tablename','dbo' X|B;>q
9、存储更改全部表 < 3+&DV-<N
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch h}<ZZ
@OldOwner as NVARCHAR(128), pC.T)k
@NewOwner as NVARCHAR(128) : )*Ge3
AS m-FDCiN>
DECLARE @Name as NVARCHAR(128) &B,& *Lp
DECLARE @Owner as NVARCHAR(128) .E8p-R5)V>
DECLARE @OwnerName as NVARCHAR(128) T[=cKYp8\
DECLARE curObject CURSOR FOR Qi]Z)v{^
select 'Name' = name, ,%G2>PBt
'Owner' = user_name(uid) LsZ!':LN
from sysobjects 3kQ8*S
where user_name(uid)=@OldOwner SpiC0
order by name *K^O oS
OPEN curObject #]/T9:
FETCH NEXT FROM curObject INTO @Name, @Owner Ca"+t
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WHILE(@@FETCH_STATUS=0) S&)
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BEGIN g*imswj7
if @Owner=@OldOwner R2ZQBwB
begin AFJY!ou~6
set @OwnerName = @OldOwner + '.' + rtrim(@Name) IGV.0l
exec sp_changeobjectowner @OwnerName, @NewOwner 1>{-wL4rc
end __%E!*m"<_
-- select @name,@NewOwner,@OldOwner \k-juF80
FETCH NEXT FROM curObject INTO @Name, @Owner _%%"Y}
END (>`SS#(T!
close curObject
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;
deallocate curObject w:+#,,rwzV
GO Bzt`9lg
10、SQL SERVER中直接循环写入数据 QNwAuH T
declare @i int r:rJv
set @i=1 F76h
while @i<30 _VJwC|
begin oT{yttSNo
insert into test (userid) values(@i) 9yAu<a
set @i=@i+1 1Sk6[h'CL
end ,PxQ[CGg
小记存储过程中经常用到的本周,本月,本年函数 w o9f99
Dateadd(wk,datediff(wk,0,getdate()),-1) qyfxT Q5
Dateadd(wk,datediff(wk,0,getdate()),6) 3+uoK f[
Dateadd(mm,datediff(mm,0,getdate()),0) XB 7^Ka
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) '+tT$k
Dateadd(yy,datediff(yy,0,getdate()),0) cHct|Z
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) )Dpt<}}\
上面的SQL代码只是一个时间段 ^{bEq\5&
Dateadd(wk,datediff(wk,0,getdate()),-1) [
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Dateadd(wk,datediff(wk,0,getdate()),6) M 7$4KFNp
就是表示本周时间段. g$LwXfg
下面的SQL的条件部分,就是查询时间段在本周范围内的: &J M;jSz
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) dph6aN(49
而在存储过程中 k(+u"T
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) )B4c;O4t
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) WfO$q^'?DP