MySQL 查询将 SUM 但 if 语句在其他字段中

Question

我在使用 mysql 查询时遇到问题，我想用 else if 语句选择 SUM，这就是我的故事。

我的查询:

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

上面的查询得到如下结果:

我想生成查询: 如果revenue_type=4 会改变value sum_revenue = value placement_id, 我想要的示例结果如下图所示:

谢谢你的帮助。

Answer 1

您可以使用CASE 表达式来获取结果:

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