diff --git a/SQL - MySQL for Data Analytics and Business Intelligence/15.SQL Subqueries/15.Employees_SQL_SUBQUERIES.sql b/SQL - MySQL for Data Analytics and Business Intelligence/15.SQL Subqueries/15.Employees_SQL_SUBQUERIES.sql
index a7a8421..4dc050c 100644
--- a/SQL - MySQL for Data Analytics and Business Intelligence/15.SQL Subqueries/15.Employees_SQL_SUBQUERIES.sql	
+++ b/SQL - MySQL for Data Analytics and Business Intelligence/15.SQL Subqueries/15.Employees_SQL_SUBQUERIES.sql	
@@ -1,108 +1,79 @@
-/*Extract the information about all department managers who were hired between the 1st of January 1990 and the 1st of January 1995.*/
+-- Extract the information about all department managers who were hired between the 1st of January 1990 and the 1st of January 1995.
 SELECT *
 FROM dept_manager
 WHERE emp_no IN (
-	SELECT emp_no FROM employees
+    SELECT emp_no 
+    FROM employees
     WHERE hire_date BETWEEN '1990-01-01' AND '1995-01-01'
 );
 
-/*Select the entire information for all employees whose job title is “Assistant Engineer”. 
-Hint: To solve this exercise, use the 'employees' table.*/
+-- Select the entire information for all employees whose job title is “Assistant Engineer”.
+-- Hint: To solve this exercise, use the 'employees' table.
 SELECT *
 FROM employees e
-WHERE EXISTS(
-	SELECT emp_no FROM titles t
-    WHERE title LIKE 'Assistant Engineer'
+WHERE EXISTS (
+    SELECT 1 
+    FROM titles t
+    WHERE t.title = 'Assistant Engineer'
     AND e.emp_no = t.emp_no
 );
 
-/*Starting your code with “DROP TABLE”, create a table called “emp_manager” 
-(emp_no – integer of 11, not null; dept_no – CHAR of 4, null; manager_no – integer of 11, not null). */
+-- Starting your code with “DROP TABLE”, create a table called “emp_manager” 
+-- (emp_no – integer of 11, not null; dept_no – CHAR of 4, null; manager_no – integer of 11, not null).
 DROP TABLE IF EXISTS emp_manager;
 
-CREATE TABLE emp_manager(
-	emp_no INT NOT NULL,
+CREATE TABLE emp_manager (
+    emp_no INT NOT NULL,
     dept_no CHAR(4) NULL,
     manager_no INT NOT NULL
 );
 
-
-/*Fill emp_manager with data about employees, the number of the department they are working in, and their managers.
-Your output must contain 42 rows.*/
-INSERT INTO emp_manager
+-- Fill emp_manager with data about employees, the number of the department they are working in, and their managers.
+-- Your output must contain 42 rows.
+INSERT INTO emp_manager (emp_no, dept_no, manager_no)
 SELECT 
-    u.*
-FROM
-    (SELECT 
-        a.*
-    FROM
-        (SELECT 
-        e.emp_no AS employee_ID,
-            MIN(de.dept_no) AS department_code,
-            (SELECT 
-                    emp_no
-                FROM
-                    dept_manager
-                WHERE
-                    emp_no = 110022) AS manager_ID
-    FROM
-        employees e
+    u.emp_no, u.dept_no, u.manager_no
+FROM (
+    SELECT 
+        e.emp_no AS emp_no,
+        MIN(de.dept_no) AS dept_no,
+        110022 AS manager_no
+    FROM employees e
     JOIN dept_emp de ON e.emp_no = de.emp_no
-    WHERE
-        e.emp_no <= 10020
+    WHERE e.emp_no <= 10020
     GROUP BY e.emp_no
-    ORDER BY e.emp_no) AS a UNION SELECT 
-        b.*
-    FROM
-        (SELECT 
-        e.emp_no AS employee_ID,
-            MIN(de.dept_no) AS department_code,
-            (SELECT 
-                    emp_no
-                FROM
-                    dept_manager
-                WHERE
-                    emp_no = 110039) AS manager_ID
-    FROM
-        employees e
+
+    UNION
+
+    SELECT 
+        e.emp_no AS emp_no,
+        MIN(de.dept_no) AS dept_no,
+        110039 AS manager_no
+    FROM employees e
     JOIN dept_emp de ON e.emp_no = de.emp_no
-    WHERE
-        e.emp_no > 10020
+    WHERE e.emp_no > 10020
     GROUP BY e.emp_no
-    ORDER BY e.emp_no
-    LIMIT 20) AS b UNION SELECT 
-        c.*
-    FROM
-        (SELECT 
-        e.emp_no AS employee_ID,
-            MIN(de.dept_no) AS department_code,
-            (SELECT 
-                    emp_no
-                FROM
-                    dept_manager
-                WHERE
-                    emp_no = 110039) AS manager_ID
-    FROM
-        employees e
-    JOIN dept_emp de ON e.emp_no = de.emp_no
-    WHERE
-        e.emp_no = 110022
-    GROUP BY e.emp_no) AS c UNION SELECT 
-        d.*
-    FROM
-        (SELECT 
-        e.emp_no AS employee_ID,
-            MIN(de.dept_no) AS department_code,
-            (SELECT 
-                    emp_no
-                FROM
-                    dept_manager
-                WHERE
-                    emp_no = 110022) AS manager_ID
-    FROM
-        employees e
+    LIMIT 20
+
+    UNION
+
+    SELECT 
+        e.emp_no AS emp_no,
+        MIN(de.dept_no) AS dept_no,
+        110039 AS manager_no
+    FROM employees e
     JOIN dept_emp de ON e.emp_no = de.emp_no
-    WHERE
-        e.emp_no = 110039
-    GROUP BY e.emp_no) AS d) as u;
+    WHERE e.emp_no = 110022
+    GROUP BY e.emp_no
+
+    UNION
 
+    SELECT 
+        e.emp_no AS emp_no,
+        MIN(de.dept_no) AS dept_no,
+        110022 AS manager_no
+    FROM employees e
+    JOIN dept_emp de ON e.emp_no = de.emp_no
+    WHERE e.emp_no = 110039
+    GROUP BY e.emp_no
+) u;