MySQL的查詢將SUM，但如果在其他領域的語句

Question

我遇到了一個MySQL查詢的麻煩，我想選擇SUM，否則如果語句，這是我的故事。

我的查詢：

SELECT SUM(s.total_revenue) AS sum_revenue, m.revenue_type AS revenue_type, d.campaignid AS placement_id 
FROM ox_data_summary_ad_hourly AS s 
INNER JOIN ox_banners AS d ON (d.bannerid = s.ad_id) 
INNER JOIN ox_campaigns AS m ON (m.campaignid = d.campaignid) 
INNER JOIN ox_clients AS a ON (a.clientid = m.clientid) 
WHERE a.type = 0 
GROUP BY placement_id 
LIMIT 0 , 30 

而在上面的查詢得到的結果如下：

我要生成查詢，其中： 如果revenue_type = 4將值改爲sum_revenue =值placement_id， 示例結果我想要如下圖所示：

謝謝你的幫助。

Answer 1

可以使用CASE表達式得到的結果：

SELECT 
    case 
     when m.revenue_type = 4 
     then d.campaignid 
     else SUM(s.total_revenue) end AS sum_revenue, 
    m.revenue_type AS revenue_type, 
    d.campaignid AS placement_id 
FROM ox_data_summary_ad_hourly AS s 
INNER JOIN ox_banners AS d 
    ON (d.bannerid = s.ad_id) 
INNER JOIN ox_campaigns AS m 
    ON (m.campaignid = d.campaignid) 
INNER JOIN ox_clients AS a 
    ON (a.clientid = m.clientid) 
WHERE a.type = 0 
GROUP BY placement_id 
LIMIT 0 , 30 

Answer 2

SELECT情況下m.revenue_type = 4，則d.campaignid其他SUM（s.total_revenue）AS sum_revenue結束，m.revenue_type AS revenue_type ，d.campaignid AS PLACEMENT_ID FROM ox_data_summary_ad_hourly爲S INNER JOIN ox_banners AS d ON（d.bannerid = s.ad_id） INNER JOIN ox_campaigns AS米ON（m.campaignid = d.campaignid） INNER JOIN ox_clients AS一個ON （a.clientid = m.clientid） WHERE a.type = 0 GROUP BY放置_id 限制0，30