SQL -- Aggregate Functions (AVG)

Select the average price of all of the items ordered that were purchased in the month of Dec.

SELECT AVG(price)

FROM items_ordered

WHERE order_date LIKE '%Dec%';

SQL -- conditional selections

In the last example the condition was first should equal 'Eric'. Besides equal here are other conditional clauses used in SQL:

= Equal

> Greater than

< Less than

>= Greater than or equal

<= Less than or equal

<> Not equal to

LIKE pattern matching operator, use "%" as character wild card

Here is an example:

select first,

       last,

       city

  from empinfo

where city <>

  'Payson';

SQL -- Selecting Data

select *

                from empinfo

                where first = 'Eric'

The above examples SQL query selects all (*) columns from the empinfo table where the first name is Eric. See result of the query below.