mySQL Theory

mySQL Theory

1. GROUP BY

   • Used in aggregate functions
   • Group by result by one or more columns

2. WHERE

   • Used to extract only records in specified condition

3. HAVING

   • Introduced because WHERE cannot be used with aggregate functions

4. ORDER BY

   • Group one or more columns in a particular order

5. DROP

   • Remove an db object such as a table

6. DELETE

   • Remove content of a db object