Method distinct_on

datafusion/core/src/dataframe/mod.rs:964–978

Return a new `DataFrame` with duplicated rows removed as per the specified expression list according to the provided sorting expressions grouped by the `DISTINCT ON` clause expressions. # Example ``` # use datafusion::prelude::*; # use datafusion::error::Result; # use datafusion_common::assert_batches_sorted_eq; # #[tokio::main] # async fn main() -> Result<()> { let ctx = SessionContext::new(); l

(
        self,
        on_expr: Vec<Expr>,
        select_expr: Vec<Expr>,
        sort_expr: Option<Vec<SortExpr>>,
    )

    /// # }
    /// ```
    pub fn distinct_on(
        self,
        on_expr: Vec<Expr>,
        select_expr: Vec<Expr>,
        sort_expr: Option<Vec<SortExpr>>,
    ) -> Result<DataFrame> {
        let plan = LogicalPlanBuilder::from(self.plan)
            .distinct_on(on_expr, select_expr, sort_expr)?
            .build()?;
        Ok(DataFrame {
            session_state: self.session_state,
            plan,
            projection_requires_validation: true,
        })
    }

    /// Return a new `DataFrame` that has statistics for a DataFrame.
    ///