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我有以下代碼:別名子查詢不工作
SELECT
CU.customer_ID AS "Customer ID",
CU.cust_LNAME AS "Last Name",
CU.cust_FNAME AS "First Name",
RH.movie_ID AS "Movie ID",
MO.movie_title AS "Movie Title",
MO.release_year AS "Release Year",
(
SELECT COUNT(*) FROM RentalHistory RH2 WHERE RH2.movie_ID = RH.movie_ID AND RH2.customer_ID = RH.customer_ID HAVING COUNT(*) > 1
) "Nbr. Of Times Rented"
FROM Customer CU
RIGHT JOIN Rentalhistory RH ON (RH.customer_ID = CU.customer_ID)
INNER JOIN Movie MO ON (MO.movie_ID = RH.movie_ID)
GROUP BY CU.customer_ID, RH.movie_ID
HAVING "Nbr. Of Times Rented" > 1
ORDER BY CU.cust_LNAME ASC, CU.cust_FNAME ASC;
我不斷收到無效的標識符別名子查詢?任何想法,我做錯了什麼?
實際上確實在某種程度上工作,客戶字段顯示爲空,可能必須調整JOIN來解決該問題。 – user3015045
@ user3015045。 。 。如果您在租賃歷史記錄表中存在不在客戶表中的'customer_id'(或者它們恰好在客戶表中爲「NULL」),就會發生這種情況。在大多數數據庫中,您不需要'Customer'和'RentalHistory'之間的'right join'。 –