软件开发高手须掌握的4大SQL精髓语句（三）

软件开发高手须掌握的4大SQL精髓语句（三）

                马根峰

(广东联合电子收费股份有限公司,广州 510300)

 

作者博客：

CSDN博客：http://blog.csdn.net/magenfeng

新浪博客： http://blog.sina.com.cn/magenfeng

QQ空间： http://user.qzone.qq.com/630414817/main#!

 

 

 

0       引言  

 

随着计算机在社会各领域应用的深入，软件开发人员不得不面临着或多或少的数据处理、数据库访问。

在SQL（Structured Query Language）语言DML中，有四大语句堪称其精髓部分。下面就讲述一下其中之一，WITH AS语句的用法。

WITH AS短语，也叫做子查询部分，可以让你做很多事情，定义一个SQL片断，该SQL片断会被整个SQL语句所用到。有的时候，是为了让SQL语句的可读性更高些，也有可能是在UNION ALL的不同部分，作为提供数据的部分。

特别对于UNION ALL比较有用。因为UNIONALL的每个部分可能相同，但是如果每个部分都去执行一遍的话，则成本太高，所以可以使用WITH AS短语，则只要执行一遍即可。

 

语法如下：

[ WITH table_name ]

AS

(query_definition )

 

 

 

 

1       本例所用工具简单说明

 

下面就以DB2数据库为例，以“万能数据库查询分析器”中文版本《DB查询分析器》、英文版本《DB Query Analyzer》作为客户端工具来来演示一下Inner Join和 Outer Join语句的用法。

之所以选择“万能数据库查询分析器”作为客户端工具，主要是因为，一方面，“万能数据库查询分析器”具有强大的功能、友好的操作界面、良好的操作性、跨越数据库平台。在《程序员》2007第2期的“新产品&工具点评”部分，编辑“特别推荐”了“万能数据库查询分析器”发布。

另一方面，截止到目前，中文版本《DB查询分析器》在国内最著名的软件下载网站“中关村在线”中下载量近9万次，位居整个数据库类排行谤中前20位。

 

 

 

  

2       “万能数据库查询分析器”中文版本《DB查询分析器》为例

 

下面就以DB2数据库为例，以“万能数据库查询分析器”英文版本《DB查询分析器》在Windows XP上运行，来作为客户端工具来来演示一下With As结合Outer Join、 Inner Join语句的使用。 

 

运行《DB查询分析器》，连接上数据源unit4_2,然后输入以下命令：

 

with w_XROADLEVELas

(

   select *from TB_XROADLEVELwhere (areano,roadno)in

   (select areano,roadnofrom tb_roadwhere level=2)

) 

select u.incroadno,r.roadname,squaddate,

sum(casewhen u.areano=4407and u.outroadno= 1then unpaymoney/100.0else 0end)as out__1,

sum(casewhen u.areano=4407and u.outroadno= 2then unpaymoney/100.0else 0end)as out__2,

sum(casewhen u.areano=4407and u.outroadno= 17then unpaymoney/100.0else 0end)as out_17,

sum(casewhen u.areano=4407and u.outroadno= 22then unpaymoney/100.0else 0end)as out_22,

sum(casewhen u.areano=4407and u.outroadno= 27then unpaymoney/100.0else 0end)as out_27,

sum(casewhen u.areano=4407and u.outroadno= 37then unpaymoney/100.0else 0end)as out_37,

sum(casewhen u.areano=4407and u.outroadno= 40then unpaymoney/100.0else 0end)as out_40,

sum(casewhen u.areano=4407and u.outroadno= 41then unpaymoney/100.0else 0end)as out_41,

sum(casewhen u.areano=4407and u.outroadno= 48then unpaymoney/100.0else 0end)as out_48,

sum(casewhen u.areano=4407and u.outroadno= 49then unpaymoney/100.0else 0end)as out_49,

sum(casewhen u.areano=4407and u.outroadno= 50then unpaymoney/100.0else 0end)as out_50,

sum(casewhen u.areano=4407and u.outroadno= 57then unpaymoney/100.0else 0end)as out_57,

sum(casewhen u.areano=4407and u.outroadno= 58then unpaymoney/100.0else 0end)as out_58,

sum(casewhen u.areano=4407and u.outroadno= 60then unpaymoney/100.0else 0end)as out_60,

sum(casewhen u.areano=4407and u.outroadno= 63then unpaymoney/100.0else 0end)as out_63,

sum(casewhen u.areano=4407and u.outroadno= 70then unpaymoney/100.0else 0end)as out_70,

sum(casewhen u.areano=4407and u.outroadno= 71then unpaymoney/100.0else 0end)as out_71,

sum(casewhen u.areano=4407and u.outroadno= 75then unpaymoney/100.0else 0end)as out_75,

sum(casewhen u.areano=4407and u.outroadno= 80then unpaymoney/100.0else 0end)as out_80,

sum(casewhen u.areano=4407and u.outroadno= 83then unpaymoney/100.0else 0end)as out_83,

sum(casewhen u.areano=4407and u.outroadno= 84then unpaymoney/100.0else 0end)as out_84,

sum(casewhen u.areano=4407and u.outroadno=262then unpaymoney/100.0else 0end)as out262,

sum(casewhen u.areano=4407and u.outroadno=263then unpaymoney/100.0else 0end)as out263,

sum(casewhen u.areano=4407and u.outroadno=264then unpaymoney/100.0else 0end)as out264,

sum(casewhen u.areano=4407and u.outroadno=265then unpaymoney/100.0else 0end)as out265,

sum(casewhen u.areano=4407and u.outroadno=266then unpaymoney/100.0else 0end)as out266,

sum(casewhen u.areano=4407and u.outroadno=267then unpaymoney/100.0else 0end)as out267,

sum(casewhen u.areano=4407and u.outroadno=268then unpaymoney/100.0else 0end)as out268,

sum(casewhen u.areano=4407and u.outroadno=269then unpaymoney/100.0else 0end)as out269,

sum(casewhen u.areano=4407and u.outroadno=272then unpaymoney/100.0else 0end)as out272,

sum(casewhen u.areano=4407and u.outroadno=273then unpaymoney/100.0else 0end)as out273 

from

(

 select a.areano,a.SquadDate,a.unpaymoney,

       case ri.levelwhen 0then a.incroadnowhen 3then xi.roadno

            endas incroadno,

 

       case ro.levelwhen 0then a.outroadnowhen 3then xo.roadno

            endas outroadno

 from w_unpay_veh a

 innerjoin tb_road rion a.areano=ri.areanoand a.incroadno=ri.roadno

 innerjoin tb_road roon a.areano=ro.areanoand a.outroadno=ro.roadno

 leftouterjoin w_XROADLEVEL xion xi.areano=a.areanoand xi.SUBROADNO=a.incroadno

 leftouterjoin w_XROADLEVEL xoon xo.areano=a.areanoand xo.SUBROADNO=a.outroadno

 where SQUADDATE>='2012-08-01' and SQUADDATE<'2012-09-01'

)as u, tb_road r

where r.areano=4407and u.areano=r.areanoand u.incroadno=r.roadno

groupby u.incroadno,r.roadname,squaddateorderby u.incroadno,squaddate;

 

          图1  输入SQL语句，准备执行（一）

 

 

          图2  输入SQL语句，准备执行（二）

 

 

 

           图3  执行结果                        

 

 

 

3       “万能数据库查询分析器”英文版本《DB Query Analzyer》为例

 

下面就以DB2数据库为例，以“万能数据库查询分析器”英文版本《DB Query Analyzer》在Windows 2000上运行，来作为客户端工具来来演示一下With As结合Outer Join、 Inner Join语句的使用。 

 

运行《DB Query Analyzer》，连接上数据源unit4_2,然后输入以下命令：

 

with w_XROADLEVELas

(

   select *from TB_XROADLEVELwhere (areano,roadno)in

   (select areano,roadnofrom tb_roadwhere level=2)

) 

select u.incroadno,r.roadname,squaddate,

sum(casewhen u.areano=4407and u.outroadno= 1then unpaymoney/100.0else 0end)as out__1,

sum(casewhen u.areano=4407and u.outroadno= 2then unpaymoney/100.0else 0end)as out__2,

sum(casewhen u.areano=4407and u.outroadno= 17then unpaymoney/100.0else 0end)as out_17,

sum(casewhen u.areano=4407and u.outroadno= 22then unpaymoney/100.0else 0end)as out_22,

sum(casewhen u.areano=4407and u.outroadno= 27then unpaymoney/100.0else 0end)as out_27,

sum(casewhen u.areano=4407and u.outroadno= 37then unpaymoney/100.0else 0end)as out_37,

sum(casewhen u.areano=4407and u.outroadno= 40then unpaymoney/100.0else 0end)as out_40,

sum(casewhen u.areano=4407and u.outroadno= 41then unpaymoney/100.0else 0end)as out_41,

sum(casewhen u.areano=4407and u.outroadno= 48then unpaymoney/100.0else 0end)as out_48,

sum(casewhen u.areano=4407and u.outroadno= 49then unpaymoney/100.0else 0end)as out_49,

sum(casewhen u.areano=4407and u.outroadno= 50then unpaymoney/100.0else 0end)as out_50,

sum(casewhen u.areano=4407and u.outroadno= 57then unpaymoney/100.0else 0end)as out_57,

sum(casewhen u.areano=4407and u.outroadno= 58then unpaymoney/100.0else 0end)as out_58,

sum(casewhen u.areano=4407and u.outroadno= 60then unpaymoney/100.0else 0end)as out_60,

sum(casewhen u.areano=4407and u.outroadno= 63then unpaymoney/100.0else 0end)as out_63,

sum(casewhen u.areano=4407and u.outroadno= 70then unpaymoney/100.0else 0end)as out_70,

sum(casewhen u.areano=4407and u.outroadno= 71then unpaymoney/100.0else 0end)as out_71,

sum(casewhen u.areano=4407and u.outroadno= 75then unpaymoney/100.0else 0end)as out_75,

sum(casewhen u.areano=4407and u.outroadno= 80then unpaymoney/100.0else 0end)as out_80,

sum(casewhen u.areano=4407and u.outroadno= 83then unpaymoney/100.0else 0end)as out_83,

sum(casewhen u.areano=4407and u.outroadno= 84then unpaymoney/100.0else 0end)as out_84,

sum(casewhen u.areano=4407and u.outroadno=262then unpaymoney/100.0else 0end)as out262,

sum(casewhen u.areano=4407and u.outroadno=263then unpaymoney/100.0else 0end)as out263,

sum(casewhen u.areano=4407and u.outroadno=264then unpaymoney/100.0else 0end)as out264,

sum(casewhen u.areano=4407and u.outroadno=265then unpaymoney/100.0else 0end)as out265,

sum(casewhen u.areano=4407and u.outroadno=266then unpaymoney/100.0else 0end)as out266,

sum(casewhen u.areano=4407and u.outroadno=267then unpaymoney/100.0else 0end)as out267,

sum(casewhen u.areano=4407and u.outroadno=268then unpaymoney/100.0else 0end)as out268,

sum(casewhen u.areano=4407and u.outroadno=269then unpaymoney/100.0else 0end)as out269,

sum(casewhen u.areano=4407and u.outroadno=272then unpaymoney/100.0else 0end)as out272,

sum(casewhen u.areano=4407and u.outroadno=273then unpaymoney/100.0else 0end)as out273 

from

(

 select a.areano,a.SquadDate,a.unpaymoney,

       case ri.levelwhen 0then a.incroadnowhen 3then xi.roadno

            endas incroadno,

 

       case ro.levelwhen 0then a.outroadnowhen 3then xo.roadno

            endas outroadno

 from w_unpay_veh a

 innerjoin tb_road rion a.areano=ri.areanoand a.incroadno=ri.roadno

 innerjoin tb_road roon a.areano=ro.areanoand a.outroadno=ro.roadno

 leftouterjoin w_XROADLEVEL xion xi.areano=a.areanoand xi.SUBROADNO=a.incroadno

 leftouterjoin w_XROADLEVEL xoon xo.areano=a.areanoand xo.SUBROADNO=a.outroadno

 where SQUADDATE>='2012-08-01' and SQUADDATE<'2012-09-01'

)as u, tb_road r

where r.areano=4407and u.areano=r.areanoand u.incroadno=r.roadno

groupby u.incroadno,r.roadname,squaddateorderby u.incroadno,squaddate;

 

          图1  输入SQL语句，准备执行（一）

   

 

          图2  输入SQL语句，准备执行（二）

 

 

          图3  执行结果                        

 

 

 

 

 

 

DB 查询分析器 5.03  下载地址：

http://xiazai.zol.com.cn/detail/27/264455.shtml

 

 

DB Query Analyzer 5.03下载地址： 

http://xiazai.zol.com.cn/detail/43/420901.shtml

 

 

软件开发高手须掌握的4大SQL精髓语句 系列：

 

软件开发高手须掌握的4大SQL精髓语句（四）

http://blog.csdn.net/magenfeng/article/details/8050612

 

软件开发高手须掌握的4大SQL精髓语句（三）

http://blog.csdn.net/magenfeng/article/details/8015093

 

软件开发高手须掌握的4大SQL精髓语句（二）

http://blog.csdn.net/magenfeng/article/details/8003558

 

软件开发高手须掌握的4大SQL精髓语句（一）

http://blog.csdn.net/magenfeng/article/details/7969385

 

 

《程序员》“特别推荐”了“万能数据库查询分析器”：

 

在《程序员》2007第2期的“新产品&工具点评”部分，编辑“特别推荐”了“万能数据库查询分析器”发布。

http://blog.csdn.net/magenfeng/article/details/7192368

 

我

              马根峰本人的微信公众号：

              万能数据库查询分析器

 马根峰的博客：

CSDN博客：http://blog.csdn.net/magenfeng

新浪博客：  http://blog.sina.com.cn/magenfeng

官方网址：   http://www.unitedpowersoft.com/

                                       

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