Not sure what you are looking for. You will not find a much simpler tutorial than this, and understanding the nature of a database is fundemental to seeing how it can be used on the web. I suggest you take the time to print out the tutorial, and walk away from the computer. Follow the tutorial step by step, it should become clear. If it doesnt then post questions to help clarify it, and SQL people with experience will try to assist. The analogy is you cannot drive a car until you understand what the various controls do, and any programming task is similar. Ince you understand the SQL language then you you can look at how this can be parsed using PHP to create startling web based applications

Here is a SQL database in a nutshell:
It is a set of related tables. Each table has columns with names like FIrstName, LastName, Address etc etc.. In a true SQL database there are more than one table, but all the tables are linked using keys. Although not a good SQL example, a look at MSAccess can help to firm up this understanding, with some helpful graphic tools.

These columns have attributes so that thy contain data of the correct type, and possibly that each line or row of data is unique. the example in the above tutorial, is about as simple a table as you can get, as it has no relationships to other tables. So try to read . The author did a great job.... but you have to read it to understand this simple tutorial.before you will be ready for the next step of seeing how it is used in a database. If you cannot understand this, the next step will be overwhelming

Now once you can wrap your brain around what a table is, and that you can get information out of the table in the order that you want, or limited by constraints that you want. This information comes out as text, and using a language like PHP or perl, you can use this info to build a dynamic web site that gives you only the info you need.

If you want to see real world examples... You are looking at one, the Daniweb forum stores these posts in a database, and when you make a selection, it retrieves the info, and presents it in the format you see. Another good example is eBay, go and look at an ebay list of things, and then click on the the price column hyperlink, and you will get a re-ordered price list. to do this ebay sends a SQL command to its database that says "order by price ascending.... or decending"

This is an advanced area of script based programming so it takes work on the students part..