PostgreSQL - Default value for CURRENT_SETTING

Question

This is how I am accessing variable in PostgreSQL.

select CURRENT_SETTING('abc.var1')

Is there an optimal way so that I can get default value i.e. 0 in case variable doesn't exist, instead of receiving an error ?

Answer 1

Use the two parameter version of that function (which prevents an error if the variable is missing), then use coalesce():

select coalesce(current_setting('abc.var1', true), '0');