Introduction to SQL

More and more people are getting into web designing, yet many are put off by SQL for reason which I don't understand. I assure you it is very easy, in this tutorial I'll try to introduce you to the extreme basics of the structured query language.

The Database

In an SQL database there can be many tables, these tables store the data that you want to get at, let's have a look at an example os a simple table. Table: People

ID	NAME	GENDER	LOCATION	AGE
1	Bob	Male	UK	31
2	Jill	Female	USA	24
3	Joe	Male	Germany	19
4	Jeff	Male	France	46
5	Sue	Female	UK	29

Above we have a representation of a table in an SQL database. You can see why they are named tables. They have rows and columns, each row is a separate line in the database, and each column represents a data group for the table. We can use SQL to retrieve selective data, update and change data, delete data... etc from this table.

Selecting

Note that the table is named people, let's have a look at a very simple SELECT statement:

SELECT name FROM people

That's it, read it. Select name from , we are telling SQL to select the name column from the people table, what would this select?

Bob, Jill, Joe, Jeff, Sue

Simple enough right? We can select more than one column.

SELECT name, gender FROM people

This would select the name column and the gender column, what would this select?

Bob, male, Jill, female, Joe, male, Jeff, male, Sue, female

There is a short-hand way to select all of the columns.

SELECT * FROM people

The * means select all columns (id, name, gender, location and age).