There is a typo in the parameter names of the make_interval() function. The parameter names are all defined with plural, not singular as it is shown in the Postgres 13 manual.
So instead of
make_interval ( [ year int [, month int [, week int [, day int [, hour int
[, min int [, sec double precision ]]]]]]] )
it should be
make_interval ( [ years int [, months int [, weeks int [, days int [,hours
int [, mins int [, secs double precision ]]]]]]] )
Thomas
