php - 两个表一起查询，只显示一条记录

Question

我正在构建一个投票系统，我现在有一个查询，它应该选择所有的民意调查并计算每个民意调查的所有选票(位于单独的表中)。所以我的表看起来像:

Polls:  
ID  
Title  
Body

Votes:  
ID  
PollID  
Vote  (This value is either 0 or 1)

总票数看起来正常，问题是它目前只显示一条记录。

目前我的查询是这样的:

SELECT POLLS.ID, 
       POLLS.TITLE, 
       POLLS.BODY, 
       Sum(CASE 
             WHEN VOTES.VOTE = 1 
                  AND VOTES.POLLID = POLLS.ID THEN 1 
             ELSE 0 
           END) AS yay, 
       Sum(CASE 
             WHEN VOTES.VOTE = 0 
                  AND VOTES.POLLID = POLLS.ID THEN 1 
             ELSE 0 
           END) AS nay, 
       FROM     polls, 
       VOTES 
ORDER  BY POLLS.ID 

我还使用 PHP 和 Codeigniter。

Answer 1

SELECT polls.ID,polls.title,polls.body,
  SUM(case when votes.vote = 1 then 1 else 0 end) AS yay,
  SUM(case when votes.vote = 0 then 1 else 0 end) AS nay,
FROM polls 
JOIN votes ON polls.ID = votes.pollID
  GROUP BY poll.ID, polls.title, polls.body
  ORDER BY polls.ID