How can I find the percentage of records in a table in DB2? - select

Question

I have a single table - drivers
I want to know what percentage of the driver's have been terminated this month compared to all the active drivers. I think I have made it very complicated and while it does return a result it is just a 0. I tried using the cast as decimal but that doesn't work for me either as the calculation still results in 0.
WITH X AS
(
SELECT
CAST(COUNT(*) AS DECIMAL (5,2)) TERMINATED,
0 ACTIVE
FROM DRIVER WHERE
MONTH(TERMINATION_DATE) = MONTH(CURRENT TIMESTAMP) AND YEAR(TERMINATION_DATE) = YEAR(CURRENT TIMESTAMP)
UNION ALL
SELECT
0 TERMINATED,
CAST(COUNT(*) AS FLOAT) ACTIVE
FROM DRIVER WHERE
ACTIVE_IN_DISP = 'True'
)
SELECT
CAST(SUM(TERMINATED)/(SUM(ACTIVE) + SUM(TERMINATED)*100) AS DECIMAL (10,2))
FROM X

Answer 1

Your parentheses are a bit off, instead of SUM(TERMINATED)/(SUM(ACTIVE) + SUM(TERMINATED)*100)
it should read
SUM(TERMINATED)/(SUM(ACTIVE) + SUM(TERMINATED))*100
You got a too small number, that's why it wouldn't fit into two decimal places.
I would rewrite Your query like this:
WITH begin_of_month(begin_of_month) AS (VALUES CURRENT DATE - (DAY(CURRENT DATE)-1) DAYS),
X AS (
SELECT COUNT(*) AS terminated, 0 AS active
FROM driver
WHERE termination_date >= begin_of_month
AND termination_date < begin_of_month + 1 MONTH --index, if present, can be used!
UNION ALL
SELECT 0 AS terminated, COUNT(*) AS active
FROM driver
WHERE active_in_disp = 'True'
)
SELECT CAST(FLOAT(SUM(TERMINATED))/(SUM(ACTIVE) + SUM(TERMINATED))*100 AS DECIMAL (10,2)) --CAST only if You wish to display with 2 decimal places
FROM X