feat: Merge Aggregate nodes with ProjectionDropOut

Author: MazterQyou

datafusion/core/src/execution/context.rs

@@ -69,6 +69,7 @@ use crate::optimizer::common_subexpr_eliminate::CommonSubexprEliminate;
 use crate::optimizer::filter_push_down::FilterPushDown;
 use crate::optimizer::limit_push_down::LimitPushDown;
 use crate::optimizer::optimizer::{OptimizerConfig, OptimizerRule};
+use crate::optimizer::projection_drop_out::ProjectionDropOut;
 use crate::optimizer::projection_push_down::ProjectionPushDown;
 use crate::optimizer::simplify_expressions::SimplifyExpressions;
 use crate::optimizer::single_distinct_to_groupby::SingleDistinctToGroupBy;
@@ -1150,6 +1151,7 @@ impl SessionState {
                 Arc::new(EliminateFilter::new()),
                 Arc::new(CommonSubexprEliminate::new()),
                 Arc::new(EliminateLimit::new()),
+                Arc::new(ProjectionDropOut::new()),
                 Arc::new(ProjectionPushDown::new()),
                 Arc::new(FilterPushDown::new()),
                 Arc::new(LimitPushDown::new()),