Question

我有一个包含Customer_ID，Customer_Name，Address1，Address2，Mail_Address1，Mail_Address2等的表。

在某些情况下，Mail_Address1 =＆＃39;相同＆＃39;或者＆＃39; ....这基本上意味着我需要提取Address1 + Address2，否则忽略并获取Mail_Address1 + Mail_Address2。

我的伪SQL查询如下所示： -

// The query that would give me all the records with the same address as Address1 for Mailing Address //
    SELECT Customer_ID, Customer_Name, Address1 + ', ' + Address2 as Address, .... 
    FROM Customers
    Where Customer_ID != 0 AND (Mail_Address1 ='Same' or Mail_Address1 ='')

和

    SELECT Customer_ID, Customer_Name, Mail_Address1 + ', ' + Mail_Address2 as Address, .... 
    FROM Customers
    Where Customer_ID != 0 AND Mail_Address1 !='Same' AND Mail_Address1 !=''

如何组合这两个查询，以便我可以根据条件选择一个正确的地址。（相同或空字符串）。

Answer 1

您是否考虑过CASE声明？

SELECT 
CASE 
    WHEN Customer_ID != 0 AND (Mail_Address1 ='Same' OR Mail_Address1 = '')
    THEN Address1 + ', ' + Address2
    ELSE Mail_Address1 + ', ' + Mail_Address2
END AS address
FROM Customers

SQL复合查询if-else或Case语句

1 个答案: