消除 GROUP_CONCAT 中的重复行

Question

我有使用这个 sql 的重复记录：

SELECT emp.id, first_name, second_name, last_name, department, positions,  
            GROUP_CONCAT(email, " ", email_type SEPARATOR " || ") AS mails,
            GROUP_CONCAT(number, " ", number_type SEPARATOR " || ") AS numbers
            FROM geography.employee AS emp
            INNER JOIN geography.employee_email AS ee ON emp.id = ee.email_FK
            LEFT JOIN geography.employee_number AS en ON emp.id = en.number_FK
            WHERE first_name = 'John' AND last_name = 'Ausini'
            GROUP BY emp.id

所以我得到了这些邮件结果：

heyhey@abv.bg personal || heyhey@abv.bg personal || summer_geals@bwtc.co work || summer_geals@bwtc.co work || ivanov@abv.bg personal || ivanov@abv.bg personal 

对于数字：

+7654656656565 work || +7654656465655 personal || +7654656656565 work || +7654656465655 personal || +7654656656565 work || +7654656465655 personal

奇怪的是，在我的第二条记录中，邮件没有重复，邮件：

hei@abv.bg personal || hurei@abv.bg personal || burei@abv.bg personal || work@bwtc.com work

...但是在这条记录中我没有数字，也许这与顶部的数字有所不同。 我的预期输出不是这样重复每条记录的数据（对于第一条记录示例）：

heyhey@abv.bg personal || summer_geals@bwtc.co work || ivanov@abv.bg personal

...而且数字也没有重复。 DISTINCT 也不起作用（如果我把它放在 SELECT 之后），我试过了，虽然我不喜欢掩盖问题。

我在表格中的数据：

Answer 1

由于您只获取单个用户的信息，因此我会选择 Salman A 的答案；但是，如果您要为多个（或所有）用户服务，并且用户往往有很多电子邮件和号码，那么这个版本可能会更快。

SELECT emp.id, first_name, second_name, last_name, department, positions, ee.mails, en.numbers
FROM geography.employee AS emp
INNER JOIN (SELECT email_FK, GROUP_CONCAT(email, " ", email_type SEPARATOR " || ") AS mails 
            FROM geography.employee_email 
            GROUP BY email_FK
) AS ee ON emp.id = ee.email_FK
LEFT JOIN (SELECT number_FK, GROUP_CONCAT(number, " ", number_type SEPARATOR " || ") AS numbers 
           FROM geography.employee_number 
           GROUP BY number_FK
) AS en ON emp.id = en.number_FK
;

Answer 2

MySQL GROUP_CONCAT 允许您指定DISTINCT，它应该在连接之前消除重复：

SELECT
    emp.id, first_name, second_name, last_name, department, positions,
    GROUP_CONCAT(DISTINCT email, " ", email_type SEPARATOR " || ") AS mails,
    GROUP_CONCAT(DISTINCT number, " ", number_type SEPARATOR " || ") AS numbers
FROM geography.employee AS emp
INNER JOIN geography.employee_email AS ee ON emp.id = ee.email_FK
LEFT JOIN geography.employee_number AS en ON emp.id = en.number_FK
WHERE first_name = 'John' AND last_name = 'Ausini'
GROUP BY emp.id