MySQL如何将一个表中的两个数据进行除运算？

Question

1.select count(*) from wzj_visitor where fwsj='chargeRequest';
2.select count(*) from wzj_visitor;

如何写成一段sql变为1/2?

Answer 1

select sum(case when fwsj='chargeRequest' then 1 else 0 end)/count(*) from wzj_visitor