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。 Rz%+E0
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一、基础 6XB9]it6
1、说明:创建数据库 R%54!f0
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CREATE DATABASE database-name [% YCupr#
2、说明:删除数据库 YHg4WW$
drop database dbname yg/.=M
3、说明:备份sql server q[**i[+%
--- 创建 备份数据的 device
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USE master keCM}V`?"
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 42X[Huy]
--- 开始 备份 N(&,+KJ)
BACKUP DATABASE pubs TO testBack L?<V KT
4、说明:创建新表 XG_lyx%:E
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) {n2jAR9nq
根据已有的表创建新表: zjB8~ku#
A:create table tab_new like tab_old (使用旧表创建新表) @k ~Xem%<
B:create table tab_new as select col1,col2... from tab_old definition only :/d#U:I
5、说明:删除新表 dsrzXmE0
drop table tabname M>8#is(pV
6、说明:增加一个列 s#64NG
Alter table tabname add column col type ~B|K]&/]
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。 Ws.F=kS>h
7、说明:添加主键: Alter table tabname add primary key(col) #!C/~"Y*`|
说明:删除主键: Alter table tabname drop primary key(col) sDw&U?gUv
8、说明:创建索引:create [unique] index idxname on tabname(col....) "J3@Z,qW
删除索引:drop index idxname U
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注:索引是不可更改的,想更改必须删除重新建。 3Sf<oYF
9、说明:创建视图:create view viewname as select statement $oe:km1-D
删除视图:drop view viewname mp>,TOi~s7
10、说明:几个简单的基本的sql语句 7WKb|
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选择:select * from table1 where 范围 45q-x_
插入:insert into table1(field1,field2) values(value1,value2) 7;0^r#:87#
删除:delete from table1 where 范围 ebp18_a|
更新:update table1 set field1=value1 where 范围 C.Y]PdYyj
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! L+(5`Y
排序:select * from table1 order by field1,field2 [desc] pma'C\b>
总数:select count as totalcount from table1 b~WiE?
求和:select sum(field1) as sumvalue from table1 GUJx?V/[
平均:select avg(field1) as avgvalue from table1 z3[
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最大:select max(field1) as maxvalue from table1 rp{q.fy'U
最小:select min(field1) as minvalue from table1 MCjf$pZN]
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11、说明:几个高级查询运算词 `og 3P:y
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A: UNION 运算符 ofC=S$wX
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 _2R;@[f2
B: EXCEPT 运算符 Fr`"XH
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 mr,IP=e~
C: INTERSECT 运算符 {D={>0
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 a;r,*zZ="
注:使用运算词的几个查询结果行必须是一致的。 +Vl\lL
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12、说明:使用外连接 G\@uj>Z
A、left outer join: J-P>
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左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 \Z{6j&;
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c h8iic
B:right outer join: nYhI0q
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 3MPmLV#f
C:full outer join: +*Y/+.4WE$
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。 omisfu_~E
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二、提升 !YYI{BJ7:N
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) dT?/9JIv
法一:select * into b from a where 1<>1 ~4IkQ|,
法二:select top 0 * into b from a #fk#RNt
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) #e|G!'wdj
insert into b(a, b, c) select d,e,f from b; SM;UNIRVE
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@m!k+0
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 T?B753I
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. bMv[.Z@v(
4、说明:子查询(表名1:a 表名2:b) zvdIwV&oT
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) q]SH'Wd
5、说明:显示文章、提交人和最后回复时间 x(~V7L>"i
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b N3oa!PE
6、说明:外连接查询(表名1:a 表名2:b) DNyt_5j&:
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 0I2?fz)
7、说明:在线视图查询(表名1:a ) #MiO4zXgd
select * from (SELECT a,b,c FROM a) T where t.a > 1; c%+uji6
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 B7oUS}M
select * from table1 where time between time1 and time2 roe_H>
select a,b,c, from table1 where a not between 数值1 and 数值2 =5YbK1Q^
9、说明:in 的使用方法 '0&HkM{ D
select * from table1 where a [not] in ('值1','值2','值4','值6') pigu]mj
10、说明:两张关联表,删除主表中已经在副表中没有的信息 %e|UA-(
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) CoWT
11、说明:四表联查问题: +"~*L,ken0
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 ..... wgq=9\+&
12、说明:日程安排提前五分钟提醒 cFuQ>xR1
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Kq+vAp).
13、说明:一条sql 语句搞定数据库分页 t? =V<Yd1
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 1YU?+K
14、说明:前10条记录 Fx)><+-
select top 10 * form table1 where 范围 EZhk(LE
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.) n,_9Eh#WD
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) [TxvZq*4
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 w6^TwjjZ$
(select a from tableA ) except (select a from tableB) except (select a from tableC) /sPa$D
17、说明:随机取出10条数据 s:z
select top 10 * from tablename order by newid() -Y N(j\
18、说明:随机选择记录 x@pzgqi3
select newid() :?i,!0#"
19、说明:删除重复记录 L},o;p:
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) Mt%Q5^
20、说明:列出数据库里所有的表名 f}?pY"yvO
select name from sysobjects where type='U' o_[I#PT
21、说明:列出表里的所有的 :X7O4?ww
select name from syscolumns where id=object_id('TableName') zn|O)"C
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 v`:!$U*
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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 6Yqqq[#V/
显示结果: Z 8GIZ
type vender pcs Wv,?xm
电脑 A 1 T ~p>Ed 9
电脑 A 1 H;Gs0Qi;
光盘 B 2 L[Wi[S6=)g
光盘 A 2 &[yYgfsp
手机 B 3 "39mhX2
手机 C 3 P;|63"U
23、说明:初始化表table1 ,I,Zl.5
TRUNCATE TABLE table1 f;&XTF5D^
24、说明:选择从10到15的记录 z@jKzyq
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc eq9qE^[Z&
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三、技巧 2%`8
1、1=1,1=2的使用,在SQL语句组合时用的较多 :
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, t6)R37
如: (;HO3Z".q$
if @strWhere !='' ?~]mOv>
begin QP@@h4J^
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 90wnwz
end !wro7ilMB
else 'w|N}
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begin vQDR;T"]
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ye| 2gH
end V9
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我们可以直接写成 .wtYostv
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere bF +d_t
2、收缩数据库 T+!0`~`
--重建索引 vgr5j
DBCC REINDEX ZalL}?E
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DBCC INDEXDEFRAG
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--收缩数据和日志 1O90 ]c0
DBCC SHRINKDB dcE(uf
DBCC SHRINKFILE Yg1HvSw\
3、压缩数据库 HLE%f;
dbcc shrinkdatabase(dbname) ,%y!F3m
4、转移数据库给新用户以已存在用户权限 aZta%3`)
exec sp_change_users_login 'update_one','newname','oldname' u:^9ZQ+
go Y@b|/+
5、检查备份集 a]I~.$G
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' )_Iu7b
6、修复数据库 j~hvPlho
ALTER DATABASE [dvbbs] SET SINGLE_USER >vuR:4B
GO U8zs=tA
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 6%&w\<(SG
GO ',6d0>4*
ALTER DATABASE [dvbbs] SET MULTI_USER A5G@u}YS5
GO ORfMp'uP=
7、日志清除 h>/L4j*Z
SET NOCOUNT ON pJQ_G`E
DECLARE @LogicalFileName sysname, mDA1$fj"
@MaxMinutes INT, c{i\F D
@NewSize INT 2y9$ k\<xV
USE tablename -- 要操作的数据库名 pEb/ yIT"
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 1EliR uJ
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 2j[;M-3
@NewSize = 1 -- 你想设定的日志文件的大小(M) mxCqN1:#
-- Setup / initialize YXGxE&!
DECLARE @OriginalSize int Ja%isIdh
SELECT @OriginalSize = size `>k7^!Ds
FROM sysfiles ;]%Syrzp
WHERE name = @LogicalFileName 08nA}+k
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ;O({|mpS\
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + z+Ej`$E{lD
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Qgl5Jr.
FROM sysfiles
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WHERE name = @LogicalFileName #|
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CREATE TABLE DummyTrans
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(DummyColumn char (8000) not null) bX+"G}CRP
DECLARE @Counter INT, + Ui%}^ZZ
@StartTime DATETIME, S$nEflcz
@TruncLog VARCHAR(255) WAb@d=H{+>
SELECT @StartTime = GETDATE(), h{e?Fl
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' stOD5yi
DBCC SHRINKFILE (@LogicalFileName, @NewSize) R^6^{q
EXEC (@TruncLog) M` |E)Y
-- Wrap the log if necessary. FW"gj\
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired PtOYlZTe?
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 257q%"
AND (@OriginalSize * 8 /1024) > @NewSize v
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BEGIN -- Outer loop. WL<f!
SELECT @Counter = 0 ujbJ&p
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ^W[3RiG
BEGIN -- update 8s6^!e&
INSERT DummyTrans VALUES ('Fill Log') S6c>D&Q
DELETE DummyTrans ajD/)9S
SELECT @Counter = @Counter + 1 oMF[<Xf
END jp#/]>(9Z
EXEC (@TruncLog) bVds23q
END zR }vw{
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Yr 1k\q
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + -W)8Z.
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 7iH%1f
FROM sysfiles tQIz
WHERE name = @LogicalFileName A{\!nq_~N
DROP TABLE DummyTrans bN.U2 %~!
SET NOCOUNT OFF s"0Hz"[^=
8、说明:更改某个表 =tqChw
exec sp_changeobjectowner 'tablename','dbo' 0|`iop%(n
9、存储更改全部表 6i*LP(n
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch gqACIXR
@OldOwner as NVARCHAR(128), QZ_8r#2x
@NewOwner as NVARCHAR(128) L7$1 rO<
AS Z`{GjV3%wH
DECLARE @Name as NVARCHAR(128) $R/@%U)-o
DECLARE @Owner as NVARCHAR(128) !+ ??3-q
DECLARE @OwnerName as NVARCHAR(128) -y)g}D%
DECLARE curObject CURSOR FOR 4XArpKA
select 'Name' = name, `:EU~4s\
'Owner' = user_name(uid) g42Z*+P6N
from sysobjects v^(J+d_>
where user_name(uid)=@OldOwner k\lU
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order by name ^
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OPEN curObject }1Km h]
FETCH NEXT FROM curObject INTO @Name, @Owner qJ<Ghd`8v
WHILE(@@FETCH_STATUS=0) U#F(%b-LC
BEGIN 8DZ
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if @Owner=@OldOwner n.xOu`gj
begin H.[t&VO
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 0`"DYJ}d
exec sp_changeobjectowner @OwnerName, @NewOwner !i?aRI/6
end \$D41_Wt|
-- select @name,@NewOwner,@OldOwner j'nrdr6n
FETCH NEXT FROM curObject INTO @Name, @Owner ? ]hS^&
END %scQP{%aD
close curObject Mg=R**s1x%
deallocate curObject A>QAR)YP
GO t%]b`ad
10、SQL SERVER中直接循环写入数据 )TyI~5>;
declare @i int A7sva@}W
set @i=1 MnD^jcx
while @i<30 =FXq=x%9+
begin #F6!x3Z
insert into test (userid) values(@i) o.KE=zp&z
set @i=@i+1 QF9$SCmv
end T6Ks]6m_
小记存储过程中经常用到的本周,本月,本年函数
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Dateadd(wk,datediff(wk,0,getdate()),-1) nO .:f
Dateadd(wk,datediff(wk,0,getdate()),6) lsRW.h,
Dateadd(mm,datediff(mm,0,getdate()),0) ;$rh&ET
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 1c}LX.9 K
Dateadd(yy,datediff(yy,0,getdate()),0) }tUr
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Q@? {|7:
上面的SQL代码只是一个时间段 DjQgF=;
Dateadd(wk,datediff(wk,0,getdate()),-1) ^F`\B'8MF
Dateadd(wk,datediff(wk,0,getdate()),6) 5u&hp
就是表示本周时间段. vON1\$bu`
下面的SQL的条件部分,就是查询时间段在本周范围内的: QDJe:\n
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) yh"48@L'D
而在存储过程中 Ts
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select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) [p&2k&.XYe
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) DyPb]Udb: