SELECT title FROM film
WHERE film_id in (
SELECT count(inventory.inventory_id) as counter
FROM inventory
WHERE film_id = film.film_id and counter = 8
)
我正在嘗試顯示“電影”中的所有電影標題，這些電影標題在庫存中正好有 8 份可用，但我似乎無法弄清楚使用子查詢的正確方法。
uj5u.com熱心網友回復：
您必須film_id在表中分組并為子句inventory中可用的 8 個副本設定條件：HAVING
SELECT title
FROM film
WHERE film_id in (
SELECT film_id
FROM inventory
GROUP BY film_id
HAVING COUNT(*) = 8
);
uj5u.com熱心網友回復：
這應該這樣做：
SELECT title
FROM film
WHERE film_id in (SELECT FILM_ID
FROM (SELECT FILM_ID, COUNT(*) AS COUNTER
FROM INVENTORY
GROUP BY FILM_ID)
WHERE COUNTER = 8)
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