PostgreSQL adds trailing zeros to numeric

Question

Recently I migrated a DB to PostgreSQL that has some columns defined as numeric(9,3) and numeric(9,4). In testing the app I have found that when da

Answer 1

If you specify a precision and scale, Pg pads to that precision and scale.

regress=> SELECT '0'::NUMERIC(8,4);
 numeric 
---------
  0.0000
(1 row)

There's no way to turn that off. It's still the same number, and the precision is defined by the type, not the value.

If you want to have the precision defined by the value you have to use unconstrained numeric:

regress=> SELECT '0'::NUMERIC, '0.0'::NUMERIC;
 numeric | numeric 
---------+---------
       0 |     0.0                                                                                                                                                             
(1 row)