In the previous section, you were introduced to the use of the "&" operator. Operators are used in programming languages to aid in the evaluation of expressions. The following table lists operators that you should be familiar with:
| * | The multiplication operator is used when multiplying fields or values. |
| / | The divide operator is used when dividing fields or values. |
| | The minus operator is used when subtracting fields or values. |
| > | The greater-than operator is used in Where clauses to determine whether a first value is greater than the second, such as Select * From Customers Where CustomerID > 10. The result would return all the CustomerIDs after 10. |
| < | The less-than operator is used in Where clauses to determine whether a first value is less than the second, such as Select * From Customers Where CustomerID < 10. The result would return CustomerIDs 1 9. |
| >= | The greater than or equal to operator is used in Where clauses to determine whether a first value is greater than or equal to the second, such as Select * From Customers Where CustomerID >= 10. The result would return CustomerIDs 1 10. |
| <= | The less than or equal to operator is used in Where clauses to determine whether a first value is less than or equal to the second, such as Select * From Customers Where CustomerID <= 10. The result would return all the CustomerIDs starting from 10. |
| <>, != | Used to check whether a value is not equal to a second. |
| AND | Used with the Where clause in the Select statement. The AND operator returns a second value, such as Select * From Customers Where CustomerID = 1 AND CustomerID = 2. |
| OR | Used with the Where clause in the Select statement. The OR operator can be used when a certain condition needs to be met or when you can settle for a second, such as Select * From Customers Where CustomerID = 1 OR CustomerID > 2. |
| LIKE | The LIKE operator is used with Where clauses when a wildcard needs to be performed, such as Select * From Customers Where LastName LIKE 'Smi%', which would return all customers whose last names start with "Smi." |
| NOT | Typically used in conjunction with the LIKE operator, the NOT operator is used when a value is not going to be LIKE the value of a second, such as Select * From Customers Where LastName NOT LIKE 'Smi%'. |
| _ | The underscore operator is used with Where clauses and is performed when you do not know the second value, such as Select * From Customers Where BillingState LIKE 'A_', which would return all customers' states that begin with A, such as AK, AL, AR, AZ, and so on. |
| % | The multiple character operator is similar to the underscore operator except that it allows for multiple characters, whereas the underscore operator allows only for two. |
