計數一個值，然後只顯示其結果> SQL

Question

我試圖只顯示一行，如果某個值超過3. 這是我的代碼。

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 
); 

它只是不斷給我相同的輸出女巫是ID爲1

我只是想顯示cursus_id這是我的表中的3倍以上。

，請幫助我：d

Answer 1

-2已經不知道這個網站whas如此勢利

Answer 2

猜你想這樣的：

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;