diff --git a/yawn-api/src/main/kotlin/com/faire/yawn/project/YawnProjections.kt b/yawn-api/src/main/kotlin/com/faire/yawn/project/YawnProjections.kt
index 1750a64..16c94b8 100644
--- a/yawn-api/src/main/kotlin/com/faire/yawn/project/YawnProjections.kt
+++ b/yawn-api/src/main/kotlin/com/faire/yawn/project/YawnProjections.kt
@@ -1,6 +1,6 @@
 package com.faire.yawn.project
 
-import com.faire.yawn.YawnTableDef
+import com.faire.yawn.YawnDef
 import com.faire.yawn.query.YawnCompilationContext
 import org.hibernate.criterion.Projection
 import org.hibernate.criterion.Projections
@@ -28,7 +28,7 @@ object YawnProjections {
     }
 
     internal class Count<SOURCE : Any, FROM : Any?>(
-        private val columnDef: YawnTableDef<SOURCE, *>.ColumnDef<FROM>,
+        private val columnDef: YawnDef<SOURCE, *>.YawnColumnDef<FROM>,
     ) : YawnQueryProjection<SOURCE, Long> {
         override fun compile(
             context: YawnCompilationContext,
@@ -38,13 +38,13 @@ object YawnProjections {
     }
 
     fun <SOURCE : Any, FROM : Any?> count(
-        columnDef: YawnTableDef<SOURCE, *>.ColumnDef<FROM>,
+        columnDef: YawnDef<SOURCE, *>.YawnColumnDef<FROM>,
     ): YawnQueryProjection<SOURCE, Long> {
         return Count(columnDef)
     }
 
     internal class CountDistinct<SOURCE : Any, FROM : Any?>(
-        private val columnDef: YawnTableDef<SOURCE, *>.ColumnDef<FROM>,
+        private val columnDef: YawnDef<SOURCE, *>.YawnColumnDef<FROM>,
     ) : YawnQueryProjection<SOURCE, Long> {
         override fun compile(
             context: YawnCompilationContext,
@@ -54,13 +54,13 @@ object YawnProjections {
     }
 
     fun <SOURCE : Any, FROM : Any?> countDistinct(
-        columnDef: YawnTableDef<SOURCE, *>.ColumnDef<FROM>,
+        columnDef: YawnDef<SOURCE, *>.YawnColumnDef<FROM>,
     ): YawnQueryProjection<SOURCE, Long> {
         return CountDistinct(columnDef)
     }
 
     internal class SumNullable<SOURCE : Any, FROM : Number?>(
-        private val columnDef: YawnTableDef<SOURCE, *>.ColumnDef<FROM>,
+        private val columnDef: YawnDef<SOURCE, *>.YawnColumnDef<FROM>,
     ) : YawnQueryProjection<SOURCE, Long?> {
         override fun compile(
             context: YawnCompilationContext,
@@ -71,13 +71,13 @@ object YawnProjections {
 
     @JvmName("sumNullable")
     fun <SOURCE : Any, FROM : Number?> sum(
-        columnDef: YawnTableDef<SOURCE, *>.ColumnDef<FROM>,
+        columnDef: YawnDef<SOURCE, *>.YawnColumnDef<FROM>,
     ): YawnQueryProjection<SOURCE, Long?> {
         return SumNullable(columnDef)
     }
 
     internal class Sum<SOURCE : Any, FROM : Number>(
-        private val columnDef: YawnTableDef<SOURCE, *>.ColumnDef<FROM>,
+        private val columnDef: YawnDef<SOURCE, *>.YawnColumnDef<FROM>,
     ) : YawnQueryProjection<SOURCE, Long> {
         override fun compile(
             context: YawnCompilationContext,
@@ -87,13 +87,13 @@ object YawnProjections {
     }
 
     fun <SOURCE : Any, FROM : Number> sum(
-        columnDef: YawnTableDef<SOURCE, *>.ColumnDef<FROM>,
+        columnDef: YawnDef<SOURCE, *>.YawnColumnDef<FROM>,
     ): YawnQueryProjection<SOURCE, Long> {
         return Sum(columnDef)
     }
 
     internal class AvgNullable<SOURCE : Any, FROM : Any?>(
-        private val columnDef: YawnTableDef<SOURCE, *>.ColumnDef<FROM>,
+        private val columnDef: YawnDef<SOURCE, *>.YawnColumnDef<FROM>,
     ) : YawnQueryProjection<SOURCE, Double?> {
         override fun compile(
             context: YawnCompilationContext,
@@ -104,13 +104,13 @@ object YawnProjections {
 
     @JvmName("avgNullable")
     fun <SOURCE : Any, FROM : Number?> avg(
-        columnDef: YawnTableDef<SOURCE, *>.ColumnDef<FROM>,
+        columnDef: YawnDef<SOURCE, *>.YawnColumnDef<FROM>,
     ): YawnQueryProjection<SOURCE, Double?> {
         return AvgNullable(columnDef)
     }
 
     internal class Avg<SOURCE : Any, FROM : Number>(
-        private val columnDef: YawnTableDef<SOURCE, *>.ColumnDef<FROM>,
+        private val columnDef: YawnDef<SOURCE, *>.YawnColumnDef<FROM>,
     ) : YawnQueryProjection<SOURCE, Double> {
         override fun compile(
             context: YawnCompilationContext,
@@ -120,13 +120,13 @@ object YawnProjections {
     }
 
     fun <SOURCE : Any, FROM : Number> avg(
-        columnDef: YawnTableDef<SOURCE, *>.ColumnDef<FROM>,
+        columnDef: YawnDef<SOURCE, *>.YawnColumnDef<FROM>,
     ): YawnQueryProjection<SOURCE, Double> {
         return Avg(columnDef)
     }
 
     internal class Max<SOURCE : Any, FROM : Comparable<FROM>?>(
-        private val columnDef: YawnTableDef<SOURCE, *>.ColumnDef<FROM>,
+        private val columnDef: YawnDef<SOURCE, *>.YawnColumnDef<FROM>,
     ) : YawnQueryProjection<SOURCE, FROM> {
         override fun compile(
             context: YawnCompilationContext,
@@ -137,13 +137,13 @@ object YawnProjections {
     }
 
     fun <SOURCE : Any, FROM : Comparable<FROM>?> max(
-        columnDef: YawnTableDef<SOURCE, *>.ColumnDef<FROM>,
+        columnDef: YawnDef<SOURCE, *>.YawnColumnDef<FROM>,
     ): YawnQueryProjection<SOURCE, FROM> {
         return Max(columnDef)
     }
 
     internal class Min<SOURCE : Any, FROM : Comparable<FROM>?>(
-        private val columnDef: YawnTableDef<SOURCE, *>.ColumnDef<FROM>,
+        private val columnDef: YawnDef<SOURCE, *>.YawnColumnDef<FROM>,
     ) : YawnQueryProjection<SOURCE, FROM> {
         override fun compile(
             context: YawnCompilationContext,
@@ -154,13 +154,13 @@ object YawnProjections {
     }
 
     fun <SOURCE : Any, FROM : Comparable<FROM>?> min(
-        columnDef: YawnTableDef<SOURCE, *>.ColumnDef<FROM>,
+        columnDef: YawnDef<SOURCE, *>.YawnColumnDef<FROM>,
     ): YawnQueryProjection<SOURCE, FROM> {
         return Min(columnDef)
     }
 
     internal class GroupBy<SOURCE : Any, FROM : Any?>(
-        private val columnDef: YawnTableDef<SOURCE, *>.ColumnDef<FROM>,
+        private val columnDef: YawnDef<SOURCE, *>.YawnColumnDef<FROM>,
     ) : YawnQueryProjection<SOURCE, FROM> {
         override fun compile(
             context: YawnCompilationContext,
@@ -171,7 +171,7 @@ object YawnProjections {
     }
 
     fun <SOURCE : Any, FROM : Any?> groupBy(
-        columnDef: YawnTableDef<SOURCE, *>.ColumnDef<FROM>,
+        columnDef: YawnDef<SOURCE, *>.YawnColumnDef<FROM>,
     ): YawnQueryProjection<SOURCE, FROM> {
         return GroupBy(columnDef)
     }
diff --git a/yawn-database-test/src/test/kotlin/com/faire/yawn/database/YawnAggregationNullabilityTest.kt b/yawn-database-test/src/test/kotlin/com/faire/yawn/database/YawnAggregationNullabilityTest.kt
new file mode 100644
index 0000000..1f523d3
--- /dev/null
+++ b/yawn-database-test/src/test/kotlin/com/faire/yawn/database/YawnAggregationNullabilityTest.kt
@@ -0,0 +1,106 @@
+package com.faire.yawn.database
+
+import com.faire.yawn.project.YawnProjections
+import com.faire.yawn.setup.entities.BookTable
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Test
+
+internal class YawnAggregationNullabilityTest : BaseYawnDatabaseTest() {
+    @Test
+    fun `count with addIsNotNull`() {
+        transactor.open { session ->
+            val count = session.project(BookTable) { books ->
+                val notes = addIsNotNull(books.notes)
+                project(YawnProjections.count(notes))
+            }.uniqueResult()!!
+
+            // 3 books have notes: harry potter, lord of the rings, the hobbit
+            assertThat(count).isEqualTo(3)
+        }
+    }
+
+    @Test
+    fun `countDistinct with addIsNotNull`() {
+        transactor.open { session ->
+            val distinctCount = session.project(BookTable) { books ->
+                val notes = addIsNotNull(books.notes)
+                project(YawnProjections.countDistinct(notes))
+            }.uniqueResult()!!
+
+            // harry potter and the hobbit share the same note
+            assertThat(distinctCount).isEqualTo(2)
+        }
+    }
+
+    @Test
+    fun `sum with addIsNotNull`() {
+        transactor.open { session ->
+            val total = session.project(BookTable) { books ->
+                val rating = addIsNotNull(books.rating)
+                project(YawnProjections.sum(rating))
+            }.uniqueResult()!!
+
+            // lord of the rings (10) + the hobbit (9)
+            assertThat(total).isEqualTo(19)
+        }
+    }
+
+    @Test
+    fun `avg with addIsNotNull`() {
+        transactor.open { session ->
+            val average = session.project(BookTable) { books ->
+                val rating = addIsNotNull(books.rating)
+                project(YawnProjections.avg(rating))
+            }.uniqueResult()!!
+
+            // (10 + 9) / 2
+            assertThat(average).isEqualTo(9.5)
+        }
+    }
+
+    @Test
+    fun `max with addIsNotNull`() {
+        transactor.open { session ->
+            val maxRating = session.project(BookTable) { books ->
+                val rating = addIsNotNull(books.rating)
+                project(YawnProjections.max(rating))
+            }.uniqueResult()!!
+
+            assertThat(maxRating).isEqualTo(10)
+        }
+    }
+
+    @Test
+    fun `min with addIsNotNull`() {
+        transactor.open { session ->
+            val minRating = session.project(BookTable) { books ->
+                val rating = addIsNotNull(books.rating)
+                project(YawnProjections.min(rating))
+            }.uniqueResult()!!
+
+            assertThat(minRating).isEqualTo(9)
+        }
+    }
+
+    @Test
+    fun `groupBy with addIsNotNull`() {
+        transactor.open { session ->
+            val results = session.project(BookTable) { books ->
+                val notes = addIsNotNull(books.notes)
+                val rating = addIsNotNull(books.rating)
+                project(
+                    YawnProjections.pair(
+                        YawnProjections.groupBy(notes),
+                        YawnProjections.sum(rating),
+                    ),
+                )
+            }.list()
+
+            // lord of the rings has rating 10, the hobbit has rating 9
+            assertThat(results).containsExactlyInAnyOrder(
+                "Note for The Hobbit and Harry Potter" to 9L,
+                "Note for Lord of the Rings" to 10L,
+            )
+        }
+    }
+}