GROUP_CONCAT DISTINCT，DISTINCT无效

Question

SELECT
    GROUP_CONCAT( DISTINCT unit.`name` ORDER BY unit.`order_index` ASC SEPARATOR '/' ) AS nameGroup 
FROM
    pms_spec_unit unit
    JOIN pms_spec spec ON spec.id = unit.spec_id 
WHERE
    spec.`status` = 1 
GROUP BY
    unit.spec_id 
HAVING
    nameGroup LIKE '%年%'

重复结果

The results I got

mysql版本8.0.25

Answer 1

多亏了Akina的comment，我解决了这个问题。实际上unit.spec_id是不同的。使用SELECT DISTINCT GROUP_CONCAT(...。