Question

求SQl语句 例如：找出表中大于5的数值占总数值的比例

Answer 1

select (select count(*) from table where column>5)/(select count(*) from table) from table

Answer 2

select sum(case when column_name > 5 then 1 else 0 end) / count(*)

from table_name

追问

取出来直接是小于1的 就显示结果为0 了，如何保留小数点呢

追答

select round(sum(case when column_name > 5 then 1 else 0 end) / count(*), 2) from table_name

round是四舍五入的函数
round(数字，保留的小数位数)