postgres function returns an integer instead of numeric

Question

This postgres function should return a decimal number, but instead the result is an integer. The SQL on its own works properly. What is wrong with the function structure? An example input is a degree minute second longitude in text - '1012104.00E'

CREATE OR REPLACE FUNCTION getSEC(inORD VARCHAR)
RETURNS NUMERIC(10) AS $$
DECLARE
 sec NUMERIC(10);
BEGIN
 sec := cast(right(substring(inOrd,0,length(inOrd)-3,2)as numeric(10))/3600;
RETURN sec;
END; $$
LANGUAGE plpgsql;

Thanks in advance.

Answer 1

numeric(10) is an integer - if you look at the docs, it takes a second option (scale) that affects how many decimal places it takes, and defaults to 0.

https://www.postgresql.org/docs/current/static/datatype-numeric.html

You could cast to decimal instead:

CREATE OR REPLACE FUNCTION getSEC(inORD VARCHAR)
RETURNS NUMERIC(10) AS $$
DECLARE
 sec NUMERIC(10);
BEGIN
 sec := cast(right(substring(inOrd,0,length(inOrd)-3,2)as numeric(10))/3600;
RETURN sec;
END; $$
LANGUAGE plpgsql;

Answer 2

numeric takes both a "precision" and "scale". Precision is the total number of digits. Scale is how many of those can be to the right of the decimal. The Postgres docs provide an example .

The precision of a numeric is the total count of significant digits in the whole number, that is, the number of digits to both sides of the decimal point. The scale of a numeric is the count of decimal digits in the fractional part, to the right of the decimal point. So the number 23.5141 has a precision of 6 and a scale of 4. Integers can be considered to have a scale of zero.

If you don't provide a scale, it defaults to 0 which means you get an integer. Thus numeric(10) is an integer with a max of 10 digits. The Postgres docs find this "feature" of the SQL standard particularly useless.

(The SQL standard requires a default scale of 0, ie, coercion to integer precision. We find this a bit useless. If you're concerned about portability, always specify the precision and scale explicitly.)

If you want 1012104.00 you'd need numeric(9, 2) . 9 digits, 2 of which are to the right of the decimal.