Question

仅在两个表中的FirstName LastName和DateofBirth列都匹配的情况下，我才打算用Patientdemographics2中名为custom的列来更新Patientdemograpics中的一列。

Update PatientDemographics
Set PatientDemographics.custom = PatientDemographics2.custom       
FROM            PatientDemographics INNER JOIN
                         PatientDemographics2 ON
                         Patientdemographics.FirstName = Patientdemographics2.FirstName and
                         Patientdemographics.LastName = Patientdemographics2.LastName  and 
                         Patientdemographics.DateofBirth = Patientdemographics.DateofBirth
                         where Patientdemographics.FirstName = Patientdemographics2.FirstName and
                         Patientdemographics.LastName = Patientdemographics2.LastName  and 
                         Patientdemographics.DateofBirth = Patientdemographics.DateofBirth

Answer 1

您在ON子句的最后一个条件中输入错误：

Patientdemographics.DateofBirth = Patientdemographics.DateofBirth

应该是：

Patientdemographics.DateofBirth = Patientdemographics2.DateofBirth

，还有一个无用 WHERE子句，因为它的所有条件都已在ON子句中应用。
还使用别名使代码更简单，更易读：

Update p
Set p.custom = p2.custom       
FROM PatientDemographics AS p INNER JOIN PatientDemographics2 AS p2 
ON
  p.FirstName = p2.FirstName and
  p.LastName = p2.LastName  and 
  p.DateofBirth = p2.DateofBirth

仅当记录匹配时，才从一个表更新另一个表中的记录

1 个答案: