Question

如果某个值超过3，我只想显示一行。这是我的代码。

SELECT cursus_id 
from cursussen 
WHERE cursus_id IN(
    SELECT cursussen.cursus_id 
    from cursussen 
    INNER JOIN inschrijvingen 
    ON cursussen.cursus_id=inschrijvingen.cursus_id 
    HAVING COUNT(cursussen.cursus_id) > 3
);

它只是一直给我同样的输出女巫是id。

我只想在桌面上显示超过3次的cursus_id。

请帮助我：D

Answer 1

-2已经不知道这个网站有如此势利

Answer 2

猜猜你想要这个：

SELECT c.cursus_id, COUNT(*) AS count
  FROM cursussen c
  INNER JOIN inschrijvingen i
  ON c.cursus_id = i.cursus_id
  GROUP BY c.cursus_id
  HAVING count > 3;

或

SELECT id FROM (
  SELECT c.cursus_id AS id, COUNT(*) AS count
    FROM cursussen c
    INNER JOIN inschrijvingen i
    ON c.cursus_id = i.cursus_id
    GROUP BY c.cursus_id
    HAVING count > 3;
  ) t;

计算一个值，然后仅显示其超过＆gt; SQL

2 个答案: