SQL Wildcard

**SQL Wildcard **filters allow you to search within a string to do partial matches.

So you can use them to search for all names that begin with the letter -A-.

Or you could search for all addresses that contain the name -OAK-.

Let-s take a look at an example. I will start with a basic employee table and run the following SQL query:

select * from employee;

The results look like this:

![SQL Wildcard Results](../../assets/blog/2012/06/image_thumb2.png)

I want to find all of the employee-s with a name starting with -A-.

In order to do this, I need to use a SQL Where clause along with a **LIKE** wildcard filter.

The SQL will look like this:

select * from employee where employee_name like 'A%';

And here are the results:

![SQL Wildcard Results](../../assets/blog/2012/06/image_thumb3.png)

I filtered out the 2 rows that have an employee_name starting with -A-. (ALLEN and ADAMS).

Let-s look at the where clause of that statement in more detail:

where employee_name like 'A%';

Where - Starts the filter section of SQL

employee_name - Is the column we want to look at.

like - The comparison operator. This is how we want to compare. Some other options would be =, <=, >=, between, in, etc.

-A%- - This is the value we are looking for. We have to enclose it in **- - **(called ticks). Since the first letter inside of the ticks is an A, it will match the first character. Then we have the %. This means we don-t care how many characters come after the A. The name could contain just the A with no letters after it. It could contain the A with 1 letter after it, or it could contain the A with 100 letters after it. The % doesn-t care.

Now, there is one other wildcard that is often used. It is the -_- (underscore). This is a single character wildcard.

Let-s look at an example. I want to find all names where the second letter is -L-:

select * from employee where employee_name like '_L%';

Here are the results of the query:

In each of the 3 results, the second letter of the employee_name is an L.

That is how you use the wildcard filter in the SQL language.

Please leave any questions and comments below.