Macro query_scalar

macro_rules! query_scalar {
    ($query:expr) => { ... };
    ($query:expr, $($args:tt)*) => { ... };
}

Available on crate feature macros only.

A variant of query! which expects a single column from the query and evaluates to an instance of QueryScalar.

The name of the column is not required to be a valid Rust identifier, however you can still use the column type override syntax in which case the column name does have to be a valid Rust identifier for the override to parse properly. If the override parse fails the error is silently ignored (we just don’t have a reliable way to tell the difference). If you’re getting a different type than expected, please check to see if your override syntax is correct before opening an issue.

Wildcard overrides like in query_as! are also allowed, in which case the output type is left up to inference.

See query! for more information.