how to calculate prevalence using sql code

Question

I am trying to calculate prevalence in sql. kind of stuck in writing the code. I want to make automative code.

I have check that I have 1453477 of sample size and numbe

Answer 1

You can cast by

count(...)/count(...)::numeric(6,4) or

count(...)/count(...)::decimal

as two options.

Important point is apply cast to denominator or numerator part(in this case denominator), Do not apply to division as

(count(...)/count(...))::numeric(6,4) which again results an integer.