posgresql exclude zero division error results

I am executing a query but for sum cases

SUM( CASE WHEN dismissal_kind = 'caught' THEN 1 ELSE 0 END )

this part of the code results into zero which causes zero division error.I am trying to not show result(not select) when

SUM( CASE WHEN dismissal_kind = 'caught' THEN 1 ELSE 0 END )

Pease help.

"""select distinct bowler as b,
    count(bowler)/SUM( CASE WHEN dismissal_kind = 'caught' THEN 1 ELSE 0 END ) from deliveries
    group by bowler; """

Answer

The simplest way is to remove the else 0:

SUM( CASE WHEN dismissal_kind = 'caught' THEN 1 END )

This returns NULL if nothing matches the condition. Dividing by NULL produces NULL and not an error.

For your query however, I recommend:

select bowler as b,
       count(*) / nullif(count(*) filter (where dismissal_kind = 'caught'), 0)
from deliveries
group by bowler;

nullif() is another way to avoid division by zero. filter is the recommended (and standard) syntax for conditional aggregation.

If you want to filter out the rows that are null, you can include a having clause:

select bowler as b,
       count(*) / nullif(count(*) filter (where dismissal_kind = 'caught'), 0)
from deliveries
group by bowler
having count(*) filter (where dismissal_kind = 'caught') > 0;