diff --git a/Uebungszettel_13.sql b/Uebungszettel_13.sql
new file mode 100644
index 0000000..92aa8b9
--- /dev/null
+++ b/Uebungszettel_13.sql
@@ -0,0 +1,146 @@
+SET SERVEROUTPUT On
+
+-- 13.1
+CREATE OR REPLACE PROCEDURE Discount
+AS
+  CURSOR c_group_discount
+  IS
+  SELECT distinct s.course_no, c.description
+  FROM section s, enrollment e, course c
+  WHERE s.section_id = e.section_id
+  AND c.course_no = s.course_no
+  GROUP BY s.course_no, c.description,
+  e.section_id, s.section_id
+  HAVING COUNT(*) >=8;
+
+BEGIN
+  FOR r_group_discount IN c_group_discount LOOP
+    UPDATE course
+    SET cost = cost * .95
+    WHERE course_no = r_group_discount.course_no;
+    DBMS_OUTPUT.PUT_LINE('A 5% discount has been given to '||
+    r_group_discount.course_no||' '||r_group_discount.description);
+  END LOOP;
+END;
+/
+-- a) Es wird eine PROCEDURE namens Discount erstellt
+
+-- b)
+BEGIN
+  Discount;
+END;
+/
+
+-- c) Commit ist nicht notwendig, da Autocommit an ist
+
+--13.2
+CREATE OR REPLACE FUNCTION new_student_id
+RETURN student.student_id%TYPE
+AS
+    v_new_id student.student_id%TYPE;
+BEGIN
+    SELECT student_id_seq.NEXTVAL INTO v_new_id FROM dual;
+    RETURN v_new_id;
+END;
+/
+
+
+-- 13.3
+-- a)
+CREATE OR REPLACE PACKAGE school_api as
+  PROCEDURE discount;
+  FUNCTION new_instructor_id
+  RETURN instructor.instructor_id%TYPE;
+END school_api;
+/
+
+CREATE OR REPLACE PACKAGE BODY school_api 
+AS
+    PROCEDURE discount IS
+        CURSOR c_group_discount IS
+            SELECT DISTINCT s.course_no, c.description
+            FROM section s, enrollment e, course c
+            WHERE s.section_id = e.section_id
+            AND c.course_no = s.course_no
+            GROUP BY s.course_no, c.description,
+            e.section_id, s.section_id
+            HAVING COUNT(*) >= 8;
+
+    BEGIN
+        FOR r_group_discount IN c_group_discount LOOP
+            UPDATE course
+            SET cost = cost * .95
+            WHERE course_no = r_group_discount.course_no;
+            DBMS_OUTPUT.PUT_LINE('A 5% discount has been given to '||
+            r_group_discount.course_no||' '||r_group_discount.description);
+        END LOOP;
+    END discount;
+
+    FUNCTION new_instructor_id
+    RETURN instructor.instructor_id%TYPE IS
+        v_new_id instructor.instructor_id%TYPE;
+    BEGIN
+        SELECT instructor_id_seq.NEXTVAL INTO v_new_id FROM dual;
+        RETURN v_new_id;
+    END new_instructor_id;
+
+END school_api;
+/
+
+--13.4
+DECLARE
+  v_new_id instructor.instructor_id%TYPE;
+BEGIN
+  v_new_id := school_api.new_instructor_id;
+  DBMS_OUTPUT.PUT_LINE('New instructor ID: ' || v_new_id);
+END;
+/
+
+--13.5
+CREATE OR REPLACE PACKAGE BODY school_api 
+AS
+  PROCEDURE discount IS
+    CURSOR c_group_discount IS
+      SELECT DISTINCT s.course_no, c.description
+      FROM section s, enrollment e, course c
+      WHERE s.section_id = e.section_id
+      AND c.course_no = s.course_no
+      GROUP BY s.course_no, c.description,
+      e.section_id, s.section_id
+      HAVING COUNT(*) >= 8;
+
+  BEGIN
+    FOR r_group_discount IN c_group_discount LOOP
+      UPDATE course
+      SET cost = cost * .95
+      WHERE course_no = r_group_discount.course_no;
+      DBMS_OUTPUT.PUT_LINE('A 5% discount has been given to '||
+      r_group_discount.course_no||' '||r_group_discount.description);
+    END LOOP;
+  END discount;
+
+  FUNCTION new_instructor_id
+  RETURN instructor.instructor_id%TYPE IS
+    v_new_id instructor.instructor_id%TYPE;
+  BEGIN
+    SELECT instructor_id_seq.NEXTVAL INTO v_new_id FROM dual;
+    RETURN v_new_id;
+  END new_instructor_id;
+
+  FUNCTION get_course_descript_private (
+    p_course_no course.course_no%TYPE
+  ) RETURN course.description%TYPE IS
+    v_description course.description%TYPE;
+  BEGIN
+    SELECT description INTO v_description
+    FROM course
+    WHERE course_no = p_course_no;
+    
+    RETURN v_description;
+  EXCEPTION
+    WHEN NO_DATA_FOUND THEN
+      RETURN NULL;
+  END get_course_descript_private;
+
+END school_api;
+/
\ No newline at end of file
diff --git a/scripts_13.sql b/scripts_13.sql
new file mode 100644
index 0000000..254e110
--- /dev/null
+++ b/scripts_13.sql
@@ -0,0 +1,29 @@
+-- section 1
+CREATE OR REPLACE PROCEDURE Discount
+AS
+  CURSOR c_group_discount
+  IS
+  SELECT distinct s.course_no, c.description
+  FROM section s, enrollment e, course c
+  WHERE s.section_id = e.section_id
+  AND c.course_no = s.course_no
+  GROUP BY s.course_no, c.description,
+  e.section_id, s.section_id
+  HAVING COUNT(*) >=8;
+
+BEGIN
+  FOR r_group_discount IN c_group_discount LOOP
+    UPDATE course
+    SET cost = cost * .95
+    WHERE course_no = r_group_discount.course_no;
+    DBMS_OUTPUT.PUT_LINE('A 5% discount has been given to '||
+    r_group_discount.course_no||' '||r_group_discount.description);
+  END LOOP;
+END;
+
+-- section 3
+CREATE OR REPLACE PACKAGE school_api as
+  PROCEDURE discount;
+  FUNCTION new_instructor_id
+  RETURN instructor.instructor_id%TYPE;
+END school_api;
\ No newline at end of file