Special type without defining a special type in SQL

[emil-petras]

It would be great if we could generate custom Go types (like SpecialType), based on existing SQL types (like string), without having to define a new SQL type. Essentially, I want to create a Go type that wraps around an existing SQL type directly.

-- name: GetSpecialTypes :many SELECT id, name ::specialtype FROM table

And then have sqlc generate the following code:

type SpecialTable struct { ID int64 Name SpecialType }

This is currently possible, but you have to define a custom sql type.

Implementation:
One way to do this might be to add a tag or directive in the sqlc configuration or SQL queries. This would tell sqlc to use the desired Go type without needing a corresponding SQL type.