Method join

datafusion/core/src/dataframe/mod.rs:1282–1303

Join this `DataFrame` with another `DataFrame` using explicitly specified columns and an optional filter expression. See [`join_on`](Self::join_on) for a more concise way to specify the join condition. Since DataFusion will automatically identify and optimize equality predicates there is no performance difference between this function and `join_on` `left_cols` and `right_cols` are used to form "

(
        self,
        right: DataFrame,
        join_type: JoinType,
        left_cols: &[&str],
        right_cols: &[&str],
        filter: Option<Expr>,
    )

    /// # }
    /// ```
    pub fn join(
        self,
        right: DataFrame,
        join_type: JoinType,
        left_cols: &[&str],
        right_cols: &[&str],
        filter: Option<Expr>,
    ) -> Result<DataFrame> {
        let plan = LogicalPlanBuilder::from(self.plan)
            .join(
                right.plan,
                join_type,
                (left_cols.to_vec(), right_cols.to_vec()),
                filter,
            )?
            .build()?;
        Ok(DataFrame {
            session_state: self.session_state,
            plan,
            projection_requires_validation: true,
        })
    }

    /// Join this `DataFrame` with another `DataFrame` using the specified
    /// expressions.