消除GROUP_CONCAT中的重复行

Question

我使用此sql有重复的记录：

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

所以我得到了邮件的这些结果：

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 

和数字：

+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

...但是在此记录中，我没有数字，也许这与前一个数字有所不同。 我的预期输出不会像这样对每个记录重复数据（对于第一个记录示例）：

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

...也没有数字重复。 DISTINCT也不起作用（如果我把它放在SELECT之后），尽管我不喜欢掩盖问题，但我还是尝试了。

我在表中的数据：

Answer 1

MySQL GROUP_CONCAT允许您指定DISTINCT，它应在串联前消除重复项：

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

Answer 2

由于您仅获得单个用户的信息，因此我会推荐Salman A的答案；但是如果您要使用多个（或全部）用户，而用户往往会有很多电子邮件和电话号码，则此版本可能会更快。

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
;