Function exprlist_to_fields

datafusion/expr/src/utils.rs:755–765

Create schema fields from an expression list, for use in result set schema construction This function converts a list of expressions into a list of complete schema fields, making comprehensive determinations about each field's properties including: - **Data type**: Resolved based on expression type and input schema context - **Nullability**: Determined by expression-specific nullability rules - *

(
    exprs: impl IntoIterator<Item = &'a Expr>,
    plan: &LogicalPlan,
)

/// where each Field contains complete schema information (type, nullability, metadata)
/// and proper table reference scoping for the corresponding expression.
pub fn exprlist_to_fields<'a>(
    exprs: impl IntoIterator<Item = &'a Expr>,
    plan: &LogicalPlan,
) -> Result<Vec<(Option<TableReference>, Arc<Field>)>> {
    // Look for exact match in plan's output schema
    let input_schema = plan.schema();
    exprs
        .into_iter()
        .map(|e| e.to_field(input_schema))
        .collect()
}

/// Convert an expression into Column expression if it's already provided as input plan.
///