SQL Distinct

The SQL Distinct clause in the SQL Language allows you to remove any repeated data in a column.

Let’s take a look at the following table/query:

select * from customer; 

Here are the results from that query:

We have 6 rows and 4 columns in this table, but I only want to look at the customer_company column.

Here is the query to bring back just that column:

select customer_company from customer; 

With the following results:

Now, I want to remove the repeated companies.  So if you look at “Dell” in the picture above, you will see that it is in there twice.

That is where the “Distinct” clause comes in.  Take a look at what happens when I put distinct into the following query:

select distinct customer_company from customer; 

I get the following results:

Notice how we only have 5 rows.  That is because the extra/repeated Dell row has been removed.

So that is what the distinct clause does, it removes the repeated data elements in a column.

Please post any questions or comments below.