根據選擇更新MySQL表

Question

是否可以運行基於每行選擇的更新查詢？這裏就是我想嘗試：

UPDATE adverts SET advert_visits = (SELECT COUNT(earning_id) FROM earnings WHERE earning_advert_id = 1093) 

但我不知道如何使選擇從廣告表採用正確的advert_id的每一行？

或者，這可能只是一個完全無效的語法，我不確定。

Answer 1

只是簡單地指更新表：

UPDATE adverts 
SET advert_visits = (
    SELECT COUNT(earning_id) 
    FROM earnings 
    WHERE earning_advert_id = adverts.advert_id 
)