通过mysql中的条件计算总投票作为减去upvote与group downvote

Question

Database table: 
+----------------------------------------------+
| vote_id | user_id | vote_type | fieldset_id  |
+----------------------------------------------+
|   1     |  1      |  up       |  111         |
|   2     |  2      |  up       |  111         |
|   3     |  3      |  down     |  111         |
|   4     |  4      |  up       |  111         |
+----------------------------------------------+

Mysql查询：

select vote_type,count(vote_type) as total_vote 
   from vote_mst 
   where fieldset_id='111' 
   group by vote_type

预期输出： +3

我正在接受

+-------------------------+
| vote_type  | total_vote |
+-------------------------+
|   up       |  3         |
|   down     |  1         |
+-------------------------+

在MysQL查询中计算（Upvote-Downvote）

Answer 1

我想你想要这样的东西：

select sum(vote_type = 'up') - sum(vote_type = 'down') as net_votes,
       count(*) as total_votes
from vote_mst 
where fieldset_id = '111' ;

Answer 2

试试这个：

select `fieldset_id`,`vote_type`,SUM(IF(`vote_type`='up',1,-1)) as `total_vote` 
from `vote_mst` 
GROUP BY `fieldset_id`