select type,sum(if(numberData>=0,numberData,0)) as z, sum(if(numberData<0,numberData,0)) as f from tt group by type 如果一个类别里z或负为0的话就用null或是0代替:解释一下
如果一个类别里z或负为0的话就用null或是0代替:z不会为0吧 select type,sum(if(ifnull(numberData,0)>=0,numberData,0)) as z, sum(if(numberData<0,numberData,0)) as f from tt group by type
sum(if(numberData<0,numberData,0)) as f
from tt group by type
如果一个类别里z或负为0的话就用null或是0代替:解释一下
select type,sum(if(ifnull(numberData,0)>=0,numberData,0)) as z,
sum(if(numberData<0,numberData,0)) as f
from tt group by type