diff --git a/src/main/java/com/kamco/cd/kamcoback/postgres/repository/Inference/MapSheetLearnRepositoryImpl.java b/src/main/java/com/kamco/cd/kamcoback/postgres/repository/Inference/MapSheetLearnRepositoryImpl.java
index 07e78bbc..8d30c422 100644
--- a/src/main/java/com/kamco/cd/kamcoback/postgres/repository/Inference/MapSheetLearnRepositoryImpl.java
+++ b/src/main/java/com/kamco/cd/kamcoback/postgres/repository/Inference/MapSheetLearnRepositoryImpl.java
@@ -420,7 +420,7 @@ public class MapSheetLearnRepositoryImpl implements MapSheetLearnRepositoryCusto
 
     StringExpression pnu =
         Expressions.stringTemplate(
-            "coalesce(({0}), '')",
+            "nullif(({0}), '')",
             JPAExpressions.select(Expressions.stringTemplate("string_agg({0}, ',')", pnuEntity.pnu))
                 .from(pnuEntity)
                 .where(pnuEntity.geo.geoUid.eq(mapSheetAnalDataInferenceGeomEntity.geoUid)));