PHP function to extract a field value from a database

Question

I'm trying to get a value of a mysql database using a php function. I have a database like this:

NAME     | EMAIL                | PASSWORD  | OTHER
-------------------------------------------------------
example  | [email protected]  | password  | other
-------------------------------------------------------
example2 | [email protected] | password2 | other2

and in my PHP file I've tried to use this function:

function selectUserField($email, $field, $connection){
    $select_user = "SELECT '$field' FROM users WHERE email='$email' LIMIT 1";
    $result = mysqli_query($connection, $select_user);
    $value = mysqli_fetch_assoc($result);
    return $value[$field];
}

//And I try to echo the result of the function
$connection = new mysqli(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME);

echo selectUserField("[email protected]", "name", $connection);

But as result I get only the field name and not its content (for this example I get "NAME" and not "example"). How can i do to get the content of the database cell?

Because you're asking MySQL to return the text 'NAME' by surrounding it in single quotes, field names should be surrounded with back ticks or nothing at all so mysql understand you want a field value instead of the given text. — ahmad
– ahmad, Commented Apr 11, 2016 at 13:14

Rafique Mohammed · Accepted Answer · 2016-04-11 13:14:27Z

2

Try this

function selectUserField($email, $field, $connection){
    $select_user = "SELECT `$field` FROM users WHERE `email`='$email' LIMIT 1"; //wrap it with ` around the field or don't wrap with anything at all
    $result = mysqli_query($connection, $select_user);
    $value = mysqli_fetch_assoc($result);
    return $value[$field];
}

//And I try to echo the result of the function
$connection = new mysqli(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME);

echo selectUserField("[email protected]", "name", $connection);

answered Apr 11, 2016 at 13:14

Rafique Mohammed

3,8262 gold badges41 silver badges44 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

jackomelly · Accepted Answer · 2016-04-11 13:14:06Z

0

No quotes around $field.

"SELECT $field FROM users WHERE email='$email' LIMIT 1";

answered Apr 11, 2016 at 13:14

jackomelly

5431 gold badge8 silver badges21 bronze badges

2 Comments

paolobasso Over a year ago

Yeah, it works. Thank you! (sorry for the stupid question i think)

Tom Over a year ago

@paolobasso Please prepare your statements, don't just select an email which the user can alter, this is highly vulnerable for SQL injection.

Collectives™ on Stack Overflow

PHP function to extract a field value from a database

2 Answers 2

Comments

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related