Method join_with_expr_keys

datafusion/expr/src/logical_plan/builder.rs:1456–1515

Apply a join with both explicit equijoin and non equijoin predicates. Note this is a low level API that requires identifying specific predicate types. Most users should use [`join_on`](Self::join_on) that automatically identifies predicates appropriately. `equi_exprs` defines equijoin predicates, of the form `l = r)` for each `(l, r)` tuple. `l`, the first element of the tuple, must only refer

(
        self,
        right: LogicalPlan,
        join_type: JoinType,
        equi_exprs: (Vec<impl Into<Expr>>, Vec<impl Into<Expr>>),
        filter: Option<Expr>,
    )

    /// join. Note that `equi_exprs` predicates are evaluated more efficiently
    /// than the filter expressions, so they are preferred.
    pub fn join_with_expr_keys(
        self,
        right: LogicalPlan,
        join_type: JoinType,
        equi_exprs: (Vec<impl Into<Expr>>, Vec<impl Into<Expr>>),
        filter: Option<Expr>,
    ) -> Result<Self> {
        if equi_exprs.0.len() != equi_exprs.1.len() {
            return plan_err!("left_keys and right_keys were not the same length");
        }

        let join_key_pairs = equi_exprs
            .0
            .into_iter()
            .zip(equi_exprs.1)
            .map(|(l, r)| {
                let left_key = l.into();
                let right_key = r.into();
                let mut left_using_columns  = HashSet::new();
                expr_to_columns(&left_key, &mut left_using_columns)?;
                let normalized_left_key = normalize_col_with_schemas_and_ambiguity_check(
                    left_key,
                    &[&[self.plan.schema()]],
                    &[],
                )?;

                let mut right_using_columns = HashSet::new();
                expr_to_columns(&right_key, &mut right_using_columns)?;
                let normalized_right_key = normalize_col_with_schemas_and_ambiguity_check(
                    right_key,
                    &[&[right.schema()]],
                    &[],
                )?;

                // find valid equijoin
                find_valid_equijoin_key_pair(
                        &normalized_left_key,
                        &normalized_right_key,
                        self.plan.schema(),
                        right.schema(),
                    )?.ok_or_else(||
                        plan_datafusion_err!(
                            "can't create join plan, join key should belong to one input, error key: ({normalized_left_key},{normalized_right_key})"
                        ))
            })
            .collect::<Result<Vec<_>>>()?;

        let join = Join::try_new(
            self.plan,
            Arc::new(right),
            join_key_pairs,
            filter,
            join_type,
            JoinConstraint::On,
            NullEquality::NullEqualsNothing,
            false, // null_aware
        )?;