根据条件检索值

Question

请看下面的查询。

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 

我需要将SimScore转换成百分比，并得到所有的记录，其中SimScore小于90％。我怎样才能在SQL中做到这一点？最后一次当我这样做，它给我带来了一个类似于如下错误：Invalid use of Group function

Answer 1

你试过吗？

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; 

条件对聚合函数的结果所属的having条款，而不是where子句。