表数据
统计每个name 的指标中红 / 黄 / 绿 / 灰 灯数量. 分组 使用sum()函数
select name, zhibiao1 as '指标1', zhibiao2 as '指标2', zhibiao3 as '指标3', sum(case when zhibiao1 ='红' then 1 else 0 end) + sum(case when zhibiao2 ='红' then 1 else 0 end)+sum(case when zhibiao3 ='红' then 1 else 0 end) as red_count , sum(case when zhibiao1 ='黄' then 1 else 0 end) + sum(case when zhibiao2 ='黄' then 1 else 0 end)+sum(case when zhibiao3 ='黄' then 1 else 0 end) as yellow_count , sum(case when zhibiao1 ='绿' then 1 else 0 end) + sum(case when zhibiao2 ='绿' then 1 else 0 end)+sum(case when zhibiao3 ='绿' then 1 else 0 end) as green_count , sum(case when zhibiao1 ='灰' then 1 else 0 end) + sum(case when zhibiao2 ='灰' then 1 else 0 end)+sum(case when zhibiao3 ='灰' then 1 else 0 end) as gray_count from info group by name
标签：case,end,多个,sum,when,zhibiao1,一行,else,mysql From： https://www.cnblogs.com/Avicii2018/p/17863139.html