Method column_refs

datafusion/expr/src/expr.rs:2061–2065

Return all references to columns in this expression. # Example ``` # use std::collections::HashSet; # use datafusion_common::Column; # use datafusion_expr::col; // For an expression `a + (b * a)` let expr = col("a") + (col("b") * col("a")); let refs = expr.column_refs(); // refs contains "a" and "b" assert_eq!(refs.len(), 2); assert!(refs.contains(&Column::new_unqualified("a"))); assert!(refs.con

(&self)

    /// assert!(refs.contains(&Column::new_unqualified("b")));
    /// ```
    pub fn column_refs(&self) -> HashSet<&Column> {
        let mut using_columns = HashSet::new();
        self.add_column_refs(&mut using_columns);
        using_columns
    }

    /// Adds references to all columns in this expression to the set
    ///