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我在数据库中有四个表：
CustomerMaster, Addresses, EmailAddresses, &PhoneNumbers

Addresses, EmailAddresses, & PhoneNumbersreferenceCustomerMaster的主键。

我想创建一个查询来获取每个客户的最新客户信息CustomerMaster。我知道如何将表连接在一起，但我不知道如何利用这些字段仅从、和中的每个客户的表中TimeStamp检索最新更新的数据。AddressesEmailAddressesPhoneNumbersCustomerMaster

SQL小提琴： Working Example

客户大师：

 | CUS_PK | CUS_FirstName | CUS_LastName | CUS_AccountNum
 | 1      | mickey        | mouse        | 000001
 | 2      | donald        | duck         | 100000

地址：

 | ADD_CUS_FK | ADD_StreetAddress | ADD_City | ADD_StateProvince | ADD_PostalCode | ADD_TimeStamp
 | 1          | Disney World      | Orlando  | Florida           | 99999          | 2000-01-01 12:00:00.000
 | 1          | Disney Land       | Anaheim  | California        | 12345          | 2012-12-23 12:00:00.000
 | 2          | Disney World      | Orlando  | Florida           | 99999          | 2001-01-01 12:00:00.000

电子邮件地址：

 | EMA_CUS_FK | EMA_EmailAddress       | EMA_TimeStamp
 | 1          | supermouse@disney.com  | 2005-01-01 12:00:00.000
 | 1          | mousehouse@disney.com  | 2006-01-01 12:00:00.000
 | 2          | scrougeheir@disney.com | 2001-01-01 12:00:00.000

电话号码：

 | PHO_CUS_FK | PHO_PhoneNumber | PHO_TimeStamp
 | 1          | 999-999-9999    | 2001-01-01 12:00:00.000
 | 1          | 012-345-6789    | 2013-01-01 12:00:00.000
 | 2          | 666-867-5309    | 2001-01-01 12:00:00.000

询问：

 SELECT DISTINCT cm.CUS_FirstName, cm.CUS_LastName, cm.CUS_AccountNum,
 addr.ADD_StreetAddress, addr.ADD_City, 
 addr.ADD_StateProvince, addr.ADD_PostalCode,
 email.EMA_EmailAddress, phone.PHO_PhoneNumber
 FROM  CustomerMaster AS cm
 JOIN  Addresses AS addr
 ON    cm.CUS_PK = addr.ADD_CUS_FK
 JOIN  EmailAddresses AS email
 ON    cm.CUS_PK = email.EMA_CUS_FK
 JOIN  PhoneNumbers AS phone
 ON    cm.CUS_PK = phone.PHO_CUS_FK
 ORDER BY cm.CUS_AccountNum

当前结果：

Mickey | Mouse | 000001 | Disney World | Orlando | Florida    | 99999 | supermouse@disney.com  | 999-999-9999 
Mickey | Mouse | 000001 | Disney World | Orlando | Florida    | 99999 | supermouse@disney.com  | 012-345-6789
Mickey | Mouse | 000001 | Disney World | Orlando | Florida    | 99999 | mousehouse@disney.com  | 999-999-9999 
Mickey | Mouse | 000001 | Disney World | Orlando | Florida    | 99999 | mousehouse@disney.com  | 012-345-6789
Mickey | Mouse | 000001 | Disney Land  | Anaheim | California | 12345 | supermouse@disney.com  | 999-999-9999 
Mickey | Mouse | 000001 | Disney Land  | Anaheim | California | 12345 | supermouse@disney.com  | 012-345-6789
Mickey | Mouse | 000001 | Disney Land  | Anaheim | California | 12345 | mousehouse@disney.com  | 999-999-9999 
Mickey | Mouse | 000001 | Disney Land  | Anaheim | California | 12345 | mousehouse@disney.com  | 012-345-6789
Donald | Duck  | 100000 | Disney World | Orlando | Florida    | 99999 | scrougeheir@disney.com | 666-867-5309

期望的结果：

Mickey | Mouse | 000001 | Disney Land  | Anaheim | California | 12345 | mousehouse@disney.com  | 012-345-6789
Donald | Duck  | 100000 | Disney World | Orlando | Florida    | 99999 | scrougeheir@disney.com | 666-867-5309

我需要如何编辑现有查询以获得所需的结果集？

请提供增强的 SQL 查询（最好是 SQL Fiddle）

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2 回答 2

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显然，LEFT JOIN检查NULL是解决方案：

询问：

 SELECT DISTINCT cm.CUS_FirstName, cm.CUS_LastName, cm.CUS_AccountNum,
 addrs1.ADD_StreetAddress, addrs1.ADD_City, addrs1.ADD_StateProvince,
 addrs1.ADD_PostalCode, email1.EMA_EmailAddress, phone1.PHO_PhoneNumber
 FROM  CustomerMaster AS cm

 JOIN       Addresses AS addrs1
 ON         cm.CUS_PK = addrs1.ADD_CUS_FK  
 LEFT JOIN  Addresses AS addrs2
 ON         cm.CUS_PK = addrs2.ADD_CUS_FK
 AND        addrs1.ADD_TimeStamp < addrs2.ADD_TimeStamp

 JOIN       EmailAddresses AS email1
 ON         cm.CUS_PK = email1.EMA_CUS_FK
 LEFT JOIN  EmailAddresses AS email2
 ON         cm.CUS_PK = email2.EMA_CUS_FK
 AND        email1.EMA_TimeStamp < email2.EMA_TimeStamp

 JOIN       PhoneNumbers AS phone1
 ON         cm.CUS_PK = phone1.PHO_CUS_FK
 LEFT JOIN  PhoneNumbers AS phone2
 ON         cm.CUS_PK = phone2.PHO_CUS_FK
 AND        phone1.PHO_TimeStamp < phone2.PHO_TimeStamp

 WHERE phone2.PHO_TimeStamp IS NULL
 AND   addrs2.ADD_TimeStamp IS NULL
 AND   email2.EMA_TimeStamp IS NULL
 ORDER BY cm.CUS_AccountNum

SQL小提琴： 在这里

于 2013-05-22T00:35:39.830 回答
-1

您不能只使用子查询作为 select 子句中的字段。您希望从中获取最新值的每个表一个子查询。例如，子查询可以是降序时间戳的“TOP 1”。

于 2013-05-20T16:43:07.840 回答