diff --git a/dialect/psql/function.go b/dialect/psql/function.go
index b32e3f5c..b3883878 100644
--- a/dialect/psql/function.go
+++ b/dialect/psql/function.go
@@ -4,7 +4,6 @@ import (
 	"io"
 
 	"github.com/stephenafamo/bob"
-	"github.com/stephenafamo/bob/clause"
 	"github.com/stephenafamo/bob/expr"
 )
 
@@ -59,11 +58,22 @@ func (f *function) WriteSQL(w io.Writer, d bob.Dialect, start int) ([]any, error
 	return args, nil
 }
 
+func (f *function) FilterWhere(e ...any) *functionOver {
+	f.filter = append(f.filter, e...)
+
+	fo := &functionOver{
+		function: f,
+	}
+	fo.windowChain = &windowChain[*functionOver]{wrap: fo}
+	fo.Base = fo
+	return fo
+}
+
 func (f *function) Over(window string) *functionOver {
 	fo := &functionOver{
 		function: f,
 	}
-	fo.def = fo
+	fo.windowChain = &windowChain[*functionOver]{wrap: fo}
 	fo.Base = fo
 	return fo
 }
@@ -97,8 +107,7 @@ func (c columnDef) WriteSQL(w io.Writer, d bob.Dialect, start int) ([]any, error
 
 type functionOver struct {
 	function *function
-	clause.WindowDef
-	windowChain[*functionOver]
+	*windowChain[*functionOver]
 	expr.Chain[Expression, Expression]
 }
 
@@ -108,7 +117,7 @@ func (wr *functionOver) WriteSQL(w io.Writer, d bob.Dialect, start int) ([]any,
 		return nil, err
 	}
 
-	winargs, err := bob.ExpressIf(w, d, start+len(fargs), wr.WindowDef, true, "OVER (", ")")
+	winargs, err := bob.ExpressIf(w, d, start+len(fargs), wr.def, true, "OVER (", ")")
 	if err != nil {
 		return nil, err
 	}
diff --git a/dialect/psql/mods.go b/dialect/psql/mods.go
index f222d950..4929d81a 100644
--- a/dialect/psql/mods.go
+++ b/dialect/psql/mods.go
@@ -313,54 +313,54 @@ func (l lockChain[Q]) SkipLocked() lockChain[Q] {
 
 type windowMod[Q interface{ AppendWindow(clause.NamedWindow) }] struct {
 	name string
-	clause.WindowDef
-	windowChain[*windowMod[Q]]
+	*windowChain[*windowMod[Q]]
 }
 
 func (w windowMod[Q]) Apply(q Q) {
 	q.AppendWindow(clause.NamedWindow{
 		Name:       w.name,
-		Definition: w.WindowDef,
+		Definition: w.def,
 	})
 }
 
-type windowChain[T clause.IWindow] struct {
-	def T
+type windowChain[T any] struct {
+	def  clause.WindowDef
+	wrap T
 }
 
 func (w *windowChain[T]) From(name string) T {
 	w.def.SetFrom(name)
-	return w.def
+	return w.wrap
 }
 
 func (w *windowChain[T]) PartitionBy(condition ...any) T {
 	w.def.AddPartitionBy(condition...)
-	return w.def
+	return w.wrap
 }
 
 func (w *windowChain[T]) OrderBy(order ...any) T {
 	w.def.AddOrderBy(order...)
-	return w.def
+	return w.wrap
 }
 
 func (w *windowChain[T]) Range() T {
 	w.def.SetMode("RANGE")
-	return w.def
+	return w.wrap
 }
 
 func (w *windowChain[T]) Rows() T {
 	w.def.SetMode("ROWS")
-	return w.def
+	return w.wrap
 }
 
 func (w *windowChain[T]) Groups() T {
 	w.def.SetMode("GROUPS")
-	return w.def
+	return w.wrap
 }
 
 func (w *windowChain[T]) FromUnboundedPreceding() T {
 	w.def.SetStart("UNBOUNDED PRECEDING")
-	return w.def
+	return w.wrap
 }
 
 func (w *windowChain[T]) FromPreceding(exp any) T {
@@ -369,12 +369,12 @@ func (w *windowChain[T]) FromPreceding(exp any) T {
 			return bob.ExpressIf(w, d, start, exp, true, "", " PRECEDING")
 		}),
 	)
-	return w.def
+	return w.wrap
 }
 
 func (w *windowChain[T]) FromCurrentRow() T {
 	w.def.SetStart("CURRENT ROW")
-	return w.def
+	return w.wrap
 }
 
 func (w *windowChain[T]) FromFollowing(exp any) T {
@@ -383,7 +383,7 @@ func (w *windowChain[T]) FromFollowing(exp any) T {
 			return bob.ExpressIf(w, d, start, exp, true, "", " FOLLOWING")
 		}),
 	)
-	return w.def
+	return w.wrap
 }
 
 func (w *windowChain[T]) ToPreceding(exp any) T {
@@ -392,12 +392,12 @@ func (w *windowChain[T]) ToPreceding(exp any) T {
 			return bob.ExpressIf(w, d, start, exp, true, "", " PRECEDING")
 		}),
 	)
-	return w.def
+	return w.wrap
 }
 
 func (w *windowChain[T]) ToCurrentRow(count int) T {
 	w.def.SetEnd("CURRENT ROW")
-	return w.def
+	return w.wrap
 }
 
 func (w *windowChain[T]) ToFollowing(exp any) T {
@@ -406,30 +406,30 @@ func (w *windowChain[T]) ToFollowing(exp any) T {
 			return bob.ExpressIf(w, d, start, exp, true, "", " FOLLOWING")
 		}),
 	)
-	return w.def
+	return w.wrap
 }
 
 func (w *windowChain[T]) ToUnboundedFollowing() T {
 	w.def.SetEnd("UNBOUNDED FOLLOWING")
-	return w.def
+	return w.wrap
 }
 
 func (w *windowChain[T]) ExcludeNoOthers() T {
 	w.def.SetExclusion("NO OTHERS")
-	return w.def
+	return w.wrap
 }
 
 func (w *windowChain[T]) ExcludeCurrentRow() T {
 	w.def.SetExclusion("CURRENT ROW")
-	return w.def
+	return w.wrap
 }
 
 func (w *windowChain[T]) ExcludeGroup() T {
 	w.def.SetExclusion("GROUP")
-	return w.def
+	return w.wrap
 }
 
 func (w *windowChain[T]) ExcludeTies() T {
 	w.def.SetExclusion("TIES")
-	return w.def
+	return w.wrap
 }
diff --git a/dialect/psql/select.go b/dialect/psql/select.go
index e2ce2f64..8f1ad8a6 100644
--- a/dialect/psql/select.go
+++ b/dialect/psql/select.go
@@ -208,7 +208,9 @@ func (selectQM) Window(name string) windowMod[*SelectQuery] {
 		name: name,
 	}
 
-	m.windowChain.def = &m
+	m.windowChain = &windowChain[*windowMod[*SelectQuery]]{
+		wrap: &m,
+	}
 	return m
 }