Update README.md

Author: Pinghsuanlin

README.md

@@ -3,7 +3,7 @@ My past work in Microsoft SQL Server and Postgre environments.
 
 * The Basics.sql file contains function like CREATE TABLE, INSER INTO+VALUES, SELECT+FROM, WHERE, GROUP BY+ORDER BY statements.
 
-* In Intermediate.sql file, I played with functions like INNER/OUTER JOIN, UNION operator, CASE statement, HAVING clause, UPDATING/DELETING, ALIASING, and PARTITION BY
+* In Intermediate.sql file, I played with functions like INNER/OUTER JOIN, UNION (ALL) operator, CASE WHEN statement, HAVING clause, UPDATING/DELETING, ALIASING, and PARTITION BY.
 
 * In Advanced.sql file, I played with Common Table Expression (CTE), Temp tables, String functions, Stored procedures, and Subqueries.