diff --git a/db/StoredProcedures.sql b/db/StoredProcedures.sql
index 09eb731b4303f360d27e75c0b963cceb083297cc..5ce0b7aae749a4a7cf803e11279c3d9ae2f8e9dc 100644
--- a/db/StoredProcedures.sql
+++ b/db/StoredProcedures.sql
@@ -679,7 +679,7 @@ BEGIN
 			)
 	LIMIT 1;
 
-	RETURN mID;
+	RETURN (mID>0);
 
 END //
 
@@ -713,7 +713,7 @@ BEGIN
 	    INNER JOIN `disciplines` 		ON disciplines.ID = disciplines_teachers.DisciplineID
 	    CROSS JOIN `lessons` 			ON lessons.DisciplineTeacherID = disciplines_teachers.ID
 	    INNER JOIN `attending_groups` 	ON attending_groups.ID = lessons.AttendingGroupID
-	    CROSS JOIN `students` 			ON InternalOccurrenceChecker(students.ID, attending_groups.ID) > 0
+	    CROSS JOIN `students` 			ON InternalOccurrenceChecker(students.ID, attending_groups.ID) = TRUE
     	LEFT JOIN  `attending_groups_pool` ON attending_groups_pool.AttendingGroupID = attending_groups.ID AND attending_groups_pool.StudentID = students.ID
 	    INNER JOIN `study_groups` 		ON students.StudyGroupID = study_groups.ID
 	    WHERE 	disciplines_teachers.TeacherID = TeacherID AND