MySQL交叉表查询百分比计数？

Question

Good morning, is it possible to calculate the percentage of 2 calculated columns from a crosstab query, my cut down query is below?

Select
  a.ContactFullName As Adviser,
  Sum(Month(b.CaseDate) = 1) As Jan,
  Sum(Month(b.CaseDate) = 2) As Feb,
  Sum(Month(b.CaseDate) = 3) As Mar,
  Count(b.CaseID) As Total,
  Count(b.StatusSubmittedDate) As Comms

From
  tblcontacts a Inner Join
  tblcases b On a.ContactID = b.ContactAssignedTo
Group By
  a.ContactFullName With Rollup

This is outputting the months as columns displaying cases in each month, Total columns counts the row while Comms column counts only cases with a date. What I would like to do is calculate the percentage of Total/Comms;

Total | Comms | %_Share
100   | 50    | 50%
346   | 53    | 15%
278   | 89    | 32%

Am I looking at the the wrong way, should I be creating multiple queries to achieve?

Thanks for looking

Answer 1

Simply select another column:

Select …,
  100*Count(b.StatusSubmittedDate)/Count(b.CaseID) As `%_Share`
From …

This is 100*Comms/Total, the way your expected output indicates, not Total/Comms as you wrote in the text.

Directly reusing one calculated column to compute the value in another calculated column isn't possible, as far as I know. But the overhead for repeated evaluation of the Count shouldn't be too severe, and perhaps MySQL will even detect such common terms and compute them only once, I don't know.