How to handle an optional value returned by a query using the postgres crate?

Question

I\'m trying to get a value for a query, but this value can be NULL and I don\'t know how to handle it in Rust. Here is my code:

let stmt = conn.prepare(\"SEL         


        

Answer 1

As described in the documentation:

Nullability

In addition to the types listed above, FromSql is implemented for Option<T> where T implements FromSql. An Option<T> represents a nullable Postgres value.

Request an Option<Type> for the field that can be NULL; then the library will automatically convert NULL to None:

let rating: Option<String> = row.get("rating");