SELECT

Imagine you have a magical book that can show you any information you need from a vast library of data. The SELECT statement is your magical spell that allows you to fetch this information from your database. It’s like having a key to unlock specific parts of a massive vault of data. Let’s see how it works!

In SQL, the SELECT statement is used to fetch data from a database. Let’s break down a simple example:

SELECT name FROM celebs;

In this statement:

• SELECT: This is the clause that signals you're making a query. Every time you want to retrieve data from a database, you start with SELECT.
• name: This specifies the column from which you want to retrieve data. In this case, we're interested in the name column.
• FROM celebs: This specifies the table you're querying. Here, it's the celebs table.

So, this statement asks the database: "Hey, show me all the data in the name column from the celebs table."

Fetching Data from All Columns

But what if you want to see all the information in a table, not just one column? That's where the wildcard character * comes in handy. It tells the database, "Give me everything!"

SELECT * FROM celebs;

In this case:

• * is a special wildcard character that selects every column in the table.
• The result set will include all the columns from the celebs table.

Whenever you run a SELECT statement, it returns a new table called the result set. This result set contains the data you've asked for based on your query.

Activity

Let's put our knowledge into practice with a couple of activities!

Retrieving Specific Data

Imagine you want to know the names of all the celebrities in your celebs table. Here's the SQL command to retrieve this information:

SELECT name FROM celebs;

This will fetch all the names from the celebs table. Simple, right? Let’s see what names are in our celebrity database!

name

Justine Bieber

Beyoncé Knowles

Jeremy Lin

Taylor Swift

Retrieving All Data

Now, let’s try something different. First, delete the previous SELECT statement from your code editor. We’re going to use the wildcard character * to select all the data from the celebs table.

SELECT * FROM celebs;

This command will fetch all the columns and rows in the celebs table. Think of it as looking at the entire library rather than just a single book.

id	name	age
1	Justin Bieber	29
2	Beyoncé Knowles	42
3	Jeremy Lin	35
4	Taylor Swift	33