diff --git a/backend/src/main/java/ru/micord/ervu_dashboard/dao/LessJoinsDao.java b/backend/src/main/java/ru/micord/ervu_dashboard/dao/LessJoinsDao.java
index 7875eed8..b8cbf7fa 100644
--- a/backend/src/main/java/ru/micord/ervu_dashboard/dao/LessJoinsDao.java
+++ b/backend/src/main/java/ru/micord/ervu_dashboard/dao/LessJoinsDao.java
@@ -6,15 +6,14 @@ import java.util.Map;
 import java.util.Set;
 import java.util.stream.Collectors;
 
-import org.jooq.Condition;
-import org.jooq.Field;
+import org.jooq.*;
+
 import org.jooq.Record;
 import org.jooq.SelectConnectByStep;
 import org.jooq.SelectForUpdateStep;
 import org.jooq.SelectJoinStep;
 import org.jooq.SelectLimitStep;
 import org.jooq.SelectOnConditionStep;
-import org.jooq.SelectSelectStep;
 import org.jooq.Table;
 import org.springframework.util.CollectionUtils;
 
@@ -68,8 +67,9 @@ public class LessJoinsDao extends CustomCoalesceDao {
         ));
 
     List<Field<?>> fieldList = convertEntityColumnsToJooqFields(columns);
+    Field<?> mainPkField = QueryUtils.toJooqField(mainNodePkColumns[0], this.getDsl().dialect(), true);
     SelectJoinStep<Record> selectStep = selectByJooqColumns(fieldList, fieldsEntityNames,
-        entitiesConditionsMap
+        entitiesConditionsMap, mainPkField
     );
 
     SelectConnectByStep<Record> joinStep = buildWhereStep(selectStep,
@@ -84,11 +84,11 @@ public class LessJoinsDao extends CustomCoalesceDao {
   }
 
   private SelectJoinStep<Record> selectByJooqColumns(List<Field<?>> fieldList,
-      Set<String> fieldsEntityNames, Map<String, List<Condition>> entitiesConditionsMap) {
-    SelectSelectStep<Record> select = uniqueResult
-                                      ? getDsl().selectDistinct(fieldList)
-                                      : getDsl().select(fieldList);
-    DefaultGraphNode mainNode = graph.getMainNode();
+      Set<String> fieldsEntityNames, Map<String, List<Condition>> entitiesConditionsMap, Field<?> mainPkField) {
+      SelectIntoStep<Record> select = uniqueResult
+              ? getDsl().select(fieldList).distinctOn(mainPkField)
+              : getDsl().select(fieldList);
+      DefaultGraphNode mainNode = graph.getMainNode();
     SelectJoinStep<Record> selectJoinStep = select.from(getTableWithAlias(mainNode));
     addJoins(
         selectJoinStep, graph.getMainNodeIndex(), -1, getMatrix(),