Unsupported type NULL of column #1

[sidoki]

preliminary info:

db = sqlite
sqlx version = 0.8.5
features = [
    "runtime-tokio", 
    "tls-native-tls",
    "macros",
    "uuid",
    "chrono",
    "migrate",
    "sqlite",
    "derive",
]

Hi guys,

I encountering an issue that seems nothing wrong from the code, but have no idea.

This is the problematic code:

let result = sqlx::query_as!(
        Uuid,
        r#"
        SELECT subscriber_id
        FROM subscription_tokens
        WHERE subscription_token = $1
        "#,
        token
    )
    .fetch_optional(db_pool)
    .await
    .map_err(|e| {
        tracing::error!("Failed to execute query: {:?}", e);
        e
    })?;

    Ok(result.map(|r| r.subscriber_id))

And these are the errors:

Help me please.

[joeydewaal]

The query_as! macro maps the rows it finds (only subscriber_id in this case) to the given struct (Uuid), which would result in something like this:

let result = Uuid {
    subscriber_id: row.get(...),
};

I'm guessing here that the Uuid type is from the Uuid crate, which would result in an error. I'd recommend reading the docs for query_scalar and query_scalar! which is the macro (or function) you'd want.

However after reading the error message I think you're running into this issue, the only work around is to move away from the macro's in this case.

[sidoki]

Thanks for pointing out the issue. You're right, it seems the Uuid type can't be recognized well by the sqlx/sqlite.

I can see my code working well after altering the type into Text instead of Uuid.

Thanks @joeydewaal!