在mysql中過濾沒有重複項

Question

我從四個不同的表中獲取數據。這是我做的事：

select value_split.id, 
count(invoice_request.id) as counts, 
GROUP_CONCAT(`category`.`category_name`) as `category_name` 
from value_split 
left join invoice_request 
on invoice_request.id = value_split.id 
and MONTH(invoice_request.from_date) = '05' 
and YEAR(invoice_request.from_date) = '2016' 
and invoice_request.status = '1' 
left join `category_value` on value_split.id = category_value.id 
left join `category` on category_value.category_id = category.category_id 
where MONTH(value_split.date) = '05' 
and YEAR(value_split.date) = '2016' 
group by value_split.id, value_split.date 
limit 0, 2147483647 

預期的答案是：

id|counts|category_name 
1 | 1 | service, drop 
2 | 2 | drop 
3 | 1 | service 

但是，我得到的是：

id|counts|category_name 
1 | 5 | service, drop 
2 | 4 | drop 
3 | 5 | service 

如果我刪除線10和11，我得到的正確答案。但是，如果我包括他們，我會得到錯誤的。但是，我也想展示它。那麼，我該怎麼做才能獲得正確的輸出？這有什麼問題？

Answer 1

使用

COUNT(DISTINCT invoice_request.id) AS counts,