Why does Go treat a Postgresql numeric & decimal columns as []uint8?

Because there is no better solution. (At least wasn't until Go 1.5's big.Float). What other alternatives are there?

• Turn it into an integer. Obviously a bad solution since numerics can have a fractional part.

• Turn it into a float64. This is evil. Especially if you're working with money (where types like numeric and decimal have the most usage).

This particular database driver chooses instead to return a string containing the number - to let you decide, whether to lose some precision (by converting it into a float64 with strconv) or use a decimal/precise number library (like gmp or math/big).

Here is an issue with the answer to that questions from the developers: https://github.com/lib/pq/issues/648

It's not safe to use a float64 type for a decimal because floats can't represent all decimals. For example, decimals support exponents much larger than floats, and the coefficients of floats, when converted to their base-2 representation, will change. It is trivial in go to convert a string to a float, so we are going to keep this behavior.