How to Index PDO SQL Results Using a Column's Value as the Key?

How to Indext SQL Results Using Column Values with PDO

When working with SQL tables that have an id column, it's often desirable to use the id as the index for the resulting arrays when fetching data using PDO.

Consider the following example:

CREATE TABLE brands (
  id INT AUTO_INCREMENT,
  name VARCHAR(255),
  url VARCHAR(255)
);

If we were to fetch all rows from this table using PDO and store the results in an array, we would get something like this:

$data = $pdo->query('SELECT * FROM brands')->fetchAll();

print_r($data);

Output:

Array
(
    [0] => Array
        (
            [id] => 1
            [name] => Solidfloor
            [url] => solidfloor
        )
    [1] => Array
        (
            [id] => 2
            [name] => Quickstep
            [url] => quickstep
        )
)

As you can see, the arrays are indexed by incrementing numbers.

However, if you want to use the id column as the index, you can use the PDO::FETCH_UNIQUE constant:

$data = $pdo->query('SELECT * FROM brands')->fetchAll(PDO::FETCH_UNIQUE);

print_r($data);

Output:

Array
(
    [1] => Array
        (
            [name] => Solidfloor
            [url] => solidfloor
        )
    [2] => Array
        (
            [name] => Quickstep
            [url] => quickstep
        )
)

Now the arrays are indexed by the id column. This can be very useful when you need to access the data by id later on.

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