sql-选择更多的行作为一列

我有一个MySQL问题

我想将下一个查询的结果存入一个var中,并使用它更新到触发器中,我正在尝试将名称逗号分隔

查询返回多一行

SELECT t.naam
FROM    trefwoorden t
INNER JOIN organisaties_has_trefwoorden AS o ON (t.id_trefwoorden = o.id_trefwoorden)
WHERE   o.id_organisaties = NEW.id_organisaties;

这是触发因素

CREATE TRIGGER updCheck_After AFTER
UPDATE ON organisaties_has_trefwoorden 
FOR EACH row    

    UPDATE organisaties o
    SET    o.trefwoorden_flat = 
    (
        SELECT t.naam
        FROM    trefwoorden t
        INNER JOIN organisaties_has_trefwoorden AS o ON (t.id_trefwoorden = o.id_trefwoorden)
        WHERE   o.id_organisaties = NEW.id_organisaties;        
    )
    WHERE  o.id_organisaties = NEW.id_organisaties  

问题是有可能选择更多行作为1列逗号分隔
还是有其他解决方案？

有人建议吗？

解决方法:

UPDATE  organisaties o
SET     o.trefwoorden_flat = 
        (
        SELECT  GROUP_CONCAT(t.naam SEPARATOR ',')
        FROM    trefwoorden t
        INNER JOIN
                organisaties_has_trefwoorden AS o
        ON      t.id_trefwoorden = o.id_trefwoorden
        WHERE   o.id_organisaties = NEW.id_organisaties       
        )
WHERE   o.id_organisaties = NEW.id_organisaties  

标签：sql,mysql,database,triggers
来源： https://codeday.me/bug/20191210/2099050.html