Rather than selecting all the records from the Employee table, you can select exactly which records you’d like to work with by applying a condition. To do this, you use the WHERE command.
For example, to work with only those employees who are in the sales department:
SELECT Department, FirstName, LastName FROM Employee WHERE Department = "SALES";
The results table would look like this:
Department |
FirstName |
LastName |
SALES |
Andreas |
Smith |
SALES |
Julia |
Allan |
Here’s another example:
SELECT FirstName, LastName FROM Employee WHERE Age >= 30 ORDER BY LastName;
This returns a sorted list of employees over the age of 29.
The part of the SQL statement following the WHERE key word and preceding the ORDER BY keywords is called a condition and the ‘>=’ is called the operator. Here’s a list of all the operators you can use with Ability:
Operator |
Meaning |
= |
Exactly Equal |
!= |
Not Equal |
< |
Less Than |
> |
Greater Than |
<= |
Less Than or Equal To |
>= |
Greater Than or Equal To |
LIKE |
Partial match |
IS NULL |
Contains no data |
AND |
Must match both conditions |
OR |
Match either condition |
NOT |
Reverses logic |
IN |
Matches one of a list |
BETWEEN |
Lies in-between two values |
By using the operators together you can always define a condition to return the records you want.
See also:
Next topic - Numeric comparisons