pub fn hash_keys(
on: Option<&Expr>,
left: &[String],
right: &str,
) -> Vec<(Expr, Expr)>Expand description
The equality key pairs a hash join can use, as (left expr, right expr).
Returns an empty vector when the hash path is unavailable, in which case
the caller uses the nested loop. Note that non-equality conjuncts are NOT
extracted or rewritten — they stay in the ON expression and are evaluated
by the confirm step, so nothing here has to reason about their semantics.