diff --git a/src/main/java/org/qed/Backends/Cockroach/helperfuncs.go b/src/main/java/org/qed/Backends/Cockroach/helperfuncs.go
index 8e5aa0d..5124546 100644
--- a/src/main/java/org/qed/Backends/Cockroach/helperfuncs.go
+++ b/src/main/java/org/qed/Backends/Cockroach/helperfuncs.go
@@ -3,19 +3,19 @@ package norm
 import (
 	"github.com/cockroachdb/cockroach/pkg/sql/opt"
 	"github.com/cockroachdb/cockroach/pkg/sql/opt/memo"
-	"github.com/cockroachdb/cockroach/pkg/sql/types"
 	"github.com/cockroachdb/cockroach/pkg/util/intsets"
+	"github.com/cockroachdb/cockroach/pkg/sql/types"
 	"github.com/cockroachdb/errors"
 )
 
 func (c *CustomFuncs) HasConstantGroupingCols(
 	input memo.RelExpr, groupingPrivate *memo.GroupingPrivate,
 ) bool {
-	_, _, _, ok := c.extractConstantGroupingColsAndBuildDummy(input, groupingPrivate)
+	_, _, _, ok := c.ExtractConstantGroupingColsAndBuildDummy(input, groupingPrivate)
 	return ok
 }
 
-func (c *CustomFuncs) extractConstantGroupingColsAndBuildDummy(
+func (c *CustomFuncs) ExtractConstantGroupingColsAndBuildDummy(
 	input memo.RelExpr, groupingPrivate *memo.GroupingPrivate,
 ) (constantCols opt.ColSet, constantValues memo.ScalarListExpr, dummyCols opt.ColList, ok bool) {
 	project, ok := input.(*memo.ProjectExpr)
@@ -51,21 +51,21 @@ func (c *CustomFuncs) extractConstantGroupingColsAndBuildDummy(
 func (c *CustomFuncs) GetConstantGroupingCols(
 	input memo.RelExpr, groupingPrivate *memo.GroupingPrivate,
 ) opt.ColSet {
-	constantCols, _, _, _ := c.extractConstantGroupingColsAndBuildDummy(input, groupingPrivate)
+	constantCols, _, _, _ := c.ExtractConstantGroupingColsAndBuildDummy(input, groupingPrivate)
 	return constantCols
 }
 
 func (c *CustomFuncs) GetConstantValues(
 	input memo.RelExpr, groupingPrivate *memo.GroupingPrivate,
 ) memo.ScalarListExpr {
-	_, constantValues, _, _ := c.extractConstantGroupingColsAndBuildDummy(input, groupingPrivate)
+	_, constantValues, _, _ := c.ExtractConstantGroupingColsAndBuildDummy(input, groupingPrivate)
 	return constantValues
 }
 
 func (c *CustomFuncs) GetDummyCols(
 	input memo.RelExpr, groupingPrivate *memo.GroupingPrivate,
 ) opt.ColList {
-	_, _, dummyCols, _ := c.extractConstantGroupingColsAndBuildDummy(input, groupingPrivate)
+	_, _, dummyCols, _ := c.ExtractConstantGroupingColsAndBuildDummy(input, groupingPrivate)
 	return dummyCols
 }
 
@@ -150,7 +150,7 @@ func (c *CustomFuncs) ConstructAggregateProjectConstantToDummyJoin(
 ) memo.RelExpr {
 	project := input.(*memo.ProjectExpr)
 
-	constantCols, constantValues, dummyCols, ok := c.extractConstantGroupingColsAndBuildDummy(project, groupingPrivate)
+	constantCols, constantValues, dummyCols, ok := c.ExtractConstantGroupingColsAndBuildDummy(project, groupingPrivate)
 	if !ok {
 		panic(errors.AssertionFailedf("should have matched"))
 	}
@@ -771,7 +771,7 @@ func (c *CustomFuncs) IsSemiJoin(input memo.RelExpr) bool {
 	}
 }
 
-func (c *CustomFuncs) UnbindFiltersFromProjections(
+func (c *CustomFuncs) RebuildFiltersWithRemappedCols(
 	projections memo.ProjectionsExpr, filters memo.FiltersExpr,
 ) memo.FiltersExpr {
 	var colMap opt.ColMap
@@ -809,47 +809,6 @@ func (c *CustomFuncs) BindFiltersToProjections(
 }
 
 
-func deriveGroupByRejectNullCols(
-	mem *memo.Memo, in memo.RelExpr, disabledRules intsets.Fast,
-) opt.ColSet {
-	input := in.Child(0).(memo.RelExpr)
-	aggs := *in.Child(1).(*memo.AggregationsExpr)
-
-	var rejectNullCols opt.ColSet
-	var savedInColID opt.ColumnID
-	for i := range aggs {
-		agg := memo.ExtractAggFunc(aggs[i].Agg)
-		aggOp := agg.Op()
-
-		if aggOp == opt.ConstAggOp {
-			continue
-		}
-
-		if !opt.AggregateIgnoresNulls(aggOp) || !opt.AggregateIsNullOnEmpty(aggOp) {
-			return opt.ColSet{}
-		}
-
-		var inColID opt.ColumnID
-		if v, ok := agg.Child(0).(*memo.VariableExpr); ok {
-			inColID = v.Col
-		} else {
-			return opt.ColSet{}
-		}
-
-		if savedInColID != 0 && savedInColID != inColID {
-			return opt.ColSet{}
-		}
-		savedInColID = inColID
-
-		if !DeriveRejectNullCols(mem, input, disabledRules).Contains(inColID) {
-			return opt.ColSet{}
-		}
-
-		rejectNullCols.Add(aggs[i].Col)
-	}
-	return rejectNullCols
-}
-
 func (c *CustomFuncs) AllFiltersCanMapOnSetOp(filters memo.FiltersExpr) bool {
 	for i := range filters {
 		if !c.CanMapOnSetOp(&filters[i]) {
@@ -987,4 +946,3 @@ func (c *CustomFuncs) MakeSetPrivate(
 		OutCols:   outColsCopy,
 	}
 }
-