Function find_column_exprs

datafusion/expr/src/utils.rs:801–807

Collect all deeply nested `Expr::Column`'s. They are returned in order of appearance (depth first), and may contain duplicates.

(exprs: &[Expr])

/// Collect all deeply nested `Expr::Column`'s. They are returned in order of
/// appearance (depth first), and may contain duplicates.
pub fn find_column_exprs(exprs: &[Expr]) -> Vec<Expr> {
    exprs
        .iter()
        .flat_map(find_columns_referenced_by_expr)
        .map(Expr::Column)
        .collect()
}

pub(crate) fn find_columns_referenced_by_expr(e: &Expr) -> Vec<Column> {
    let mut exprs = vec![];