Struct WindowFunc 

pub struct WindowFunc<K> { /* private fields */ }

A bare, argument-free window function reference (row_number(), rank(), dense_rank()) — not yet a usable expression, since a window function has no meaning without an OVER (..) clause. See this module’s doc comment for why this is a separate type from Expr rather than Expr itself.

K is the row key .over(..) stamps onto the result, so a selected row_number() is readable as row.row_number() with nothing declared.

Implementations

impl<K> WindowFunc<K>

pub fn over<WindowReq>( self, window: Window<WindowReq>, ) -> Keyed<K, WindowReq, BigInt>

Every ranking function counts rows, so the result is BigInt rather than a parameter — an aggregate over a window, which would have the aggregate’s own type, is the separate shape this module defers.

Trait Implementations

impl<K: Spelled> LookupKey for WindowFunc<K>

So row.get(row_number()) works: the key is the function, and a window spec would only be noise at the lookup.

impl<K> RowKey for WindowFunc<K>

type Key = K