count_all() aggregations cannot be aliased

[BlakeOrth]

Describe the bug

Attempting to apply an alias to a count_all() aggregation results in an Internal Error with the following message:

called `Result::unwrap()` on an `Err` value: Internal("Invalid aggregate expression 'Alias(Alias { expr: AggregateFunction(AggregateFunction { func: AggregateUDF { inner: Count { name: \"count\", signature: Signature { type_signature: OneOf([VariadicAny, Nullary]), volatility: Immutable } } }, params: AggregateFunctionParams { args: [Literal(Int64(1), None)], distinct: false, filter: None, order_by: None, null_treatment: None } }), relation: None, name: \"count(*)\", metadata: None })'")

Presumably this is because count_all() already applies an alias as count(*). It looks like it's currently possible to work around this restriction by using count(lit(1)) in place of count_all().

To Reproduce

Tested using DataFusion 48.0.1, found in DataFusion 47.0.0

#[cfg(test)]
mod tests {
    use arrow::{
        array::StringArray,
        datatypes::{DataType, Field, Schema},
        record_batch::RecordBatch,
    };
    use datafusion::{functions_aggregate::count::count_all, prelude::SessionContext};
    use std::sync::Arc;

    #[tokio::test]
    async fn alias_count_all() {
        // Create a simple RecordBatch with a single row
        let schema = Schema::new(vec![Field::new("id", DataType::Utf8, false)]);
        let id_array = StringArray::from(vec!["test_id_1"]);
        let record_batch =
            RecordBatch::try_new(Arc::new(schema), vec![Arc::new(id_array)]).unwrap();

        // Create DataFusion context and DataFrame from the record batch
        let ctx = SessionContext::new();
        let df = ctx.read_batch(record_batch).unwrap();

        // Add count_all() aggregation and alias it as "TOTAL_COUNT"
        let df_with_count = df
            .aggregate(vec![], vec![count_all().alias("TOTAL_COUNT")])
            .unwrap();

        // Verify the column exists and is aliased as expected
        let results = df_with_count.collect().await.unwrap();
        assert_eq!(results.len(), 1);
        let batch = &results[0];
        let schema = batch.schema();
        let field = schema.field(0);
        assert_eq!(
            field.name(),
            "TOTAL_COUNT",
            "Column should be aliased to TOTAL_COUNT"
        );
    }
}

Expected behavior

Aliasing count_all() aggregations should result in the user supplied alias, not a runtime error.

Additional context

No response

[Loaki07]

take

[kosiew]

hi @Loaki07 ,

Are you still working on this?

[Loaki07]

yes, I'll do it.