根據條件檢索值

Question

請看下面的查詢。

SELECT `p_id`, COUNT(`p_id`) AS OverlapWords, `UniqueWordCount`, 
(COUNT(`p_id`)/`UniqueWordCount`) AS SimScore FROM `key_uniqueword` WHERE `word` IN 
('stand','on') GROUP BY (`p_id`) LIMIT 500 

我需要將SimScore轉換成百分比，並得到所有的記錄，其中SimScore小於90％。我怎樣才能在SQL中做到這一點？最後一次當我這樣做，它給我帶來了一個類似於如下錯誤：Invalid use of Group function

Answer 1

你試過嗎？

SELECT `p_id`, COUNT(`p_id`) AS OverlapWords, `UniqueWordCount`, 
     (COUNT(`p_id`)/`UniqueWordCount`) AS SimScore 
FROM `key_uniqueword` 
WHERE `word` IN ('stand','on') 
GROUP BY (`p_id`) 
HAVING SimScore < 0.9 
LIMIT 500; 

條件對聚合函數的結果所屬的having條款，而不是where子句。