根據用戶定義的限制選擇外鍵的數量

Question

我簡化了以下mysql查詢，它將table1中的主鍵作爲table2中的外鍵出現的次數。

SELECT table1.*, COUNT(table2.id) AS 'value' 

FROM table1 INNER JOIN table2 ON table1.id = table2.id 

WHERE table1.lastname LIKE 'smith' 

WHERE table1.firstname LIKE 'john' 

GROUP BY table2.id; 

我想修改它，使它只選擇那些超過一定的閾值數，也就是說，如果發生John Smith的ID在表2的10倍，而我的閾值是20，他的紀錄會不會選擇。

Answer 1

GROUP BY table2.id 
    HAVING COUNT(table2.id) >= @Threshold 

Answer 2

SELECT table1.*,table2.value as value 
FROM table1, 
(
SELECT table2.id, COUNT(table2.id) AS 'value' 

FROM table1 INNER JOIN table2 ON table1.id = table2.id 

WHERE table1.lastname LIKE 'smith' AND table1.firstname LIKE 'john' 

GROUP BY table2.id 
HAVING COUNT(table2.id)>=20 
) table2 
WHERE table1.id=table2.id;