HAVING子句中的Oracle PL/SQL變量

Question

我在將變量放在HAVING子句中遇到一些麻煩，問題是我需要COUNT（*）大於變量。

我使用Oracle數據庫XE 11.2

DECLARE 


    cnt1 NUMBER; 
    cnt2 NUMBER; 
    res NUMBER; 
BEGIN 
    SELECT COUNT(*) 
    INTO cnt1 
    FROM BESTELLING; 

    SELECT COUNT(*) 
    INTO cnt2 
    FROM ARTIKEL; 

    res := cnt1/cnt2; 
END; 
/

SELECT A.Naam, COUNT(*) AS HOEVEEL_VERKOCHT 
FROM Artikel A, Winkelwagen W 
WHERE A.Artikel_ID = W.Artikel_ID 
AND W.Datum_Besteld IS NOT NULL 
GROUP BY A.Naam 
HAVING COUNT(*) > ?res? 
ORDER BY COUNT(*) DESC; 

Answer 1

地查詢在主查詢，子查詢：

....... 
HAVING COUNT(*) > 
    ( SELECT COUNT(*) FROM BESTELLING) /
    ( SELECT COUNT(*) FROM ARTIKEL) 
ORDER BY COUNT(*) DESC; 

Answer 2

這樣的方式不會工作？

DECLARE 


    cnt1 NUMBER; 
    cnt2 NUMBER; 
    result NUMBER; 
BEGIN 
    SELECT COUNT(*) 
    INTO cnt1 
    FROM BESTELLING; 

    SELECT COUNT(*) 
    INTO cnt2 
    FROM ARTIKEL; 

    result := cnt1/cnt2; 
SELECT A.Naam, res, COUNT(*) AS HOEVEEL_VERKOCHT 
FROM Artikel A, Winkelwagen W 
WHERE A.Artikel_ID = W.Artikel_ID 
AND W.Datum_Besteld IS NOT NULL 
GROUP BY A.Naam, res 
HAVING COUNT(*) > result 
ORDER BY COUNT(*) DESC; 

END; 
/

我變變資源造成的，因爲它似乎你有列名爲res從PL/SQL直接