MYSQL - 如何選擇CASE（兩個表，如果不在一個，檢查其他）

Question

我有兩個表內的一個MySQL數據庫。

一個表包含與價值"example@example.com"

其他表不...領域

我想要做的是檢查現場兩個表與匹配"example@example.com"的值。

這裏是我的查詢不工作：

(#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 13) 

SELECT CASE WHEN 
EXISTS (
    SELECT address, suburb, city, postCode, province 
    FROM user_postal 
    INNER JOIN user_info ON user_postal.id = user_info.id 
    WHERE user_info.emailContact = 'example@example.com' 
) 
OR EXISTS (
    SELECT address, suburb, city, postCode, province 
    FROM user_postal 
    INNER JOIN user_business_info ON user_postal.id = user_business_info.id 
    WHERE user_business_info.emailContact = 'example@example.com' 
) 

我想回與電子郵件example@example.com匹配用戶的ID的字段address, suburb, city, postCode, province的值。 （這可能是在兩個表中的任何一個，但它肯定是在一個或另一個）

任何人都可以啓發我，我哪裏出錯了？任何有關這方面的信息將不勝感激。謝謝！

Answer 1

如何：

SELECT address, suburb, city, postCode, province 
FROM user_postal 
INNER JOIN user_info ON user_postal.id = user_info.id 
WHERE user_info.emailContact = 'example@example.com' 

UNION 

SELECT address, suburb, city, postCode, province 
FROM user_postal 
INNER JOIN user_business_info ON user_postal.id = user_business_info.id 
WHERE user_business_info.emailContact = 'example@example.com' 

Answer 2

這是您要使用UNION的地方。

Answer 3

SELECT address, suburb, city, postCode, province 
FROM user_postal 
     INNER JOIN user_business_info ON (user_postal.id = user_business_info.id AND user_info.emailContact = 'example@example.com') 
             OR (user_postal.id = user_info.id AND user_business_info.emailContact = 'example@example.com')