Function merge_schema

datafusion/expr/src/utils.rs:1303–1315

merge inputs schema into a single schema. This function merges schemas from multiple logical plan inputs using [`DFSchema::merge`]. Refer to that documentation for details on precedence and metadata handling.

(inputs: &[&LogicalPlan])

/// This function merges schemas from multiple logical plan inputs using [`DFSchema::merge`].
/// Refer to that documentation for details on precedence and metadata handling.
pub fn merge_schema(inputs: &[&LogicalPlan]) -> DFSchema {
    if inputs.len() == 1 {
        inputs[0].schema().as_ref().clone()
    } else {
        inputs.iter().map(|input| input.schema()).fold(
            DFSchema::empty(),
            |mut lhs, rhs| {
                lhs.merge(rhs);
                lhs
            },
        )
    }
}

/// Build state name. State is the intermediate state of the aggregate function.
pub fn format_state_name(name: &str, state_name: &str) -> String {