Question

can we still simplify this query by using the derived column to be an input of another procedure

$query = "SELECT   table1.id,
         COUNT(DISTINCT arr1.element) AS Arr1,
         COUNT(DISTINCT arr2.element) AS Arr2,
         COUNT(DISTINCT arr1.element) +
         COUNT(DISTINCT arr2.element) AS tot,
(COUNT(DISTINCT arr1.element)/(COUNT(DISTINCT arr1.element)+COUNT(DISTINCT arr2.element)))*col3 AS c31,
(COUNT(DISTINCT arr2.element)/(COUNT(DISTINCT arr1.element)+COUNT(DISTINCT arr2.element)))*col3 AS c32
FROM table1 
WHERE col2 = 'x'" 

something like this

$query = "SELECT   table1.id,
         COUNT(DISTINCT arr1.element) AS Arr1,
         COUNT(DISTINCT arr2.element) AS Arr2,
         COUNT(DISTINCT arr1.element) +
         COUNT(DISTINCT arr2.element) AS tot,
        (Arr1/tot)*col3 AS c31,
        (Arr2/tot)*col3 AS c32
FROM  table1 
WHERE col2 = 'x'" 

thanks

Answer 1

You can try this:

$query = "
SELECT tab.id, tab.Arr1, tab.Arr2, tab.tot, (tab.Arr1/tab.tot) as c31, (tab.Arr2/tab.tot) as c32
from (
SELECT   table1.id,
         COUNT(DISTINCT arr1.element) AS Arr1,
         COUNT(DISTINCT arr2.element) AS Arr2,
         COUNT(DISTINCT arr1.element) +
         COUNT(DISTINCT arr2.element) AS tot
FROM table1 
WHERE col2 = 'x'
) as 'tab' "