Issue with PHP MySQL function output

Question

I made a simple function that will go into the MYSQL DB and get the field I need based on an id. It works OUTSIDE the function. Inside the function the SQL statement is correct but I cannot figure out why it will not output the results of $row[$field]. Something I am doing wrong is not displaying when its inside the function.

function getVendor($field,$id) {
    $sql = "SELECT  $field from manufacturer where id=$id LIMIT 1";
    echo $sql;
    $result = $conn->query($sql);
    while($row = $result->fetch_assoc()) {
        echo $row[$field];
    }
}


getVendor('name','2');

`$conn` is out of scope, feed the connection object in the function arguments as well — Kevin, Aug 23 '19 at 01:43

Ezequiel Fernandez · Answer 1 · 2019-08-23T01:55:00.397

1

Your $conn is not in the function scope. Also, You don't need the while loop due the id should be unique.

function getVendor($conn, $field, $id) {

    $sql = " SELECT {$field} FROM manufacturer WHERE id={$id} ";
    $result = $conn->query($sql);
    $row = $result->fetch_assoc();
    echo $row[$field];

}


getVendor($conn, 'name','2');

edited Aug 23 '19 at 01:55

answered Aug 23 '19 at 01:43

Ezequiel Fernandez

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You don't need to quote integer value – catcon Aug 23 '19 at 01:47
3

it would even be better if you revise it into prepared statements with some column whitelisting, and since the OP is trying to select via ID, you wouldn't need a `while` block anymore since you'r expecting one row – Kevin Aug 23 '19 at 01:47
@EzequielFernandez: id possibly a number, and it's a number in this code – catcon Aug 23 '19 at 01:49
@Ghost you right! – Ezequiel Fernandez Aug 23 '19 at 01:53
you could remove `LIMIT 15` as well, it doesn't make sense having a limit and selecting with `WHERE id = ?`, you know its one row only – Kevin Aug 23 '19 at 01:54
yup I've done that!! – Ezequiel Fernandez Aug 23 '19 at 01:55

Issue with PHP MySQL function output

1 Answers1