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
