Function plan_having 

pub fn plan_having(
    having: &Expr,
    projection: &[SelectItem],
    aggregates: &mut Vec<AggregateExpr>,
    functions: &FunctionRegistry,
    scope: &TableScope,
) -> Result<Vec<Filter>>

Convert a HAVING clause into filters over finalized group rows.

aggregates is extended in place with any aggregate that appears only in HAVING, so it is computed alongside the projected ones.