Question

我正在尝试使用join语句进行查询。这就是我所拥有的：

SELECT Person.Id,  
      Person.AddressLine1, Person.AddressLine2, Person.Name, 
      Person.City
  FROM Person WITH (NOLOCK) INNER JOIN
      Customer ON 
      Customer.Id = Person.Id
  WHERE (Person.IsRegular = 1)

但是当我使用它时（我在WHERE子句中添加了另一个参数）：

SELECT Person.Id,  
      Person.AddressLine1, Person.AddressLine2, Person.Name, 
      Person.City
  FROM Person WITH (NOLOCK) INNER JOIN
      Customer ON 
      Customer.Id = Person.Id
  WHERE (Person.IsRegular = 1) AND
      (Customer.RoleType = 'XX') AND 
      (Customer.LocType = 3)

即使我的Customer表中有一行与Person.Id匹配且该特定行包含RoleType =“XX”且LocType = 3的字段，也没有结果。

更新：修好了，但现在我遇到了问题..我这样做了：

SELECT Person.Id, Person.AddressLine1, Person.AddressLine2, Person.Name, Person.City 
FROM Person WITH (NOLOCK) 
INNER JOIN Customer ON Customer.Id = Person.Id WHERE (Person.IsRegular = 1) AND (Customer.RoleType = 'XX') AND (Customer.LocType = 3) 
AS xxx ON xxx.Id=1... it says:incorrect syntax near the keyword 'AS'

Answer 1

将INNER JOIN替换为您的第二个LEFT OUTER JOIN中的SELECT，以查看Customer表中实际检测到的内容，以及它是否符合预期。< / p>

检查数据类型：例如，RoleType是CHAR字段（带填充）而不是VARCHAR？

Answer 2

您是否应该加入customerid到personid？或者客户表中是否有personid列？那些可能不匹配...... 其中一个表可能包含外键。类似的东西：

SELECT Person.Id,         
Person.AddressLine1, 
Person.AddressLine2, Person.Name,        
Person.City   
FROM Person WITH (NOLOCK) INNER JOIN Customer ON
Customer.Id = Person.CustomerId   
WHERE (Person.IsRegular = 1)

根据表的布局方式，这可能是

Customer.PersonId = Person.Id

SQL连接查询没有返回任何内容

2 个答案: