Lesson 1
Advanced uses of the SELECT statement in SQL
After you have a good understanding of what SQL can do, it is time to move on to more sophisticated queries. It's
important to understand what your database engine is capable of, and what your requirements are for pulling information
from your system.
This module will introduce you to some of the more advanced queries. These new clauses include grouping and filtering. You will see how to make sure you skip duplicate information in the database, making the information more meaningful and easier to digest.
One of the advanced uses of the Select statement is in Group functions Group functions are functions applied to a group of rows.
This module will introduce you to some of the more advanced queries. These new clauses include grouping and filtering. You will see how to make sure you skip duplicate information in the database, making the information more meaningful and easier to digest.
Examples of group functions are:
COUNT(*) - Returns the number of rows in the group. MIN(exp) - Returns the minimum value of the expression evaluated on each row of the group. MAX(exp) - Returns the maximum value of the expression evaluated on each row of the group. AVG(exp) - Returns the average value of the expression evaluated on each row of the group.
