pub fn is_empty(&self) -> bool {
        if let MirRelationExpr::Constant { rows: Ok(rows), .. } = self {
            rows.is_empty()
        } else {
            false
        }
    }
/// Indicates if this is a constant empty collection.
///
/// A false value does not mean the collection is known to be non-empty,
/// only that we cannot currently determine that it is statically empty.
Indicates if this is a constant empty collection.
A false value does not mean the collection is known to be non-empty,
only that we cannot currently determine that it is statically empty.
Indicates if this is a constant empty collection . A false value does not mean the collection is known to be non - empty only that we cannot currently determine that it is statically empty .
pub fn is_empty(&self) -> bool {
        if let MirRelationExpr::Constant { rows: Ok(rows), .. } = self {
            rows.is_empty()
        } else {
            false
        }
    }
pub fn is_empty ( & self ) -> bool { if let MirRelationExpr :: Constant { rows : Ok ( rows ) , .. } = self { rows . is_empty ( ) } else { false } }
Indicates if this is a constant empty collection.
Indicates if this is a constant empty collection .
&self
&self