mysql - 如何获取mysql中同一张表的计数值为零？

Question

这是MySql这句话

select if(b.opcionselec='Y','Yes','No') as opt, count(b.idPregunta) as val
from respuestabuleanas as b where b.idPregunta='1' group by (b.opcionselec);

查询结果

 opt           val
 No             1

我想要得到什么

 opt           val
 No             1
 Yes            0

有什么办法可以实现吗？

Answer 1

select if(b.opcionselec='Y','Yes','No') as opt, count(b.idPregunta) as val
from respuestabuleanas as b 

LEFT JOIN respuestabuleanas as b1 ON b1.idPregunta='1' group by (b.opcionselec);