Fetching data from mysql database with php

Question

I just created a page that could get the name of the students in 2 schools using their school name(This is just for my practice). But when i execute the following code i don't get the name of the top student in each school whose name is at top in the database, But i get the rest of the list.

<?php require 'connect.php'; if(isset($_GET['school'])) { $school = trim($_GET['school']); $people = $db->prepare("SELECT id, name FROM users WHERE school = ? "); $people->bind_param('s', $school); $people->execute(); $people->bind_result($id, $name); if(!$people->fetch()) { echo "Invalid School Name!!"; } else { while($people->fetch()) { echo 'ID. ',$id, ' ',$name,'<br>'; } } } ?>

This problem only occurs when i use if and else statements to output error message "Invalid School Name!!". If i just use the while loop to fetch data, i get the full list. Please tell me the why i miss the first name and a solution for this. Thank you.

@Prix No, if (!$people->fetch()) is correct (partially)

Michael Berkowski
– Michael Berkowski

2014-09-14 23:45:03 +00:00
Commented Sep 14, 2014 at 23:45 — Michael Berkowski
– Michael Berkowski, Commented Sep 14, 2014 at 23:45
Can you choose an answer if you're problem is solved? Thx

ochurlaud
– ochurlaud

2014-09-18 10:02:57 +00:00
Commented Sep 18, 2014 at 10:02 — ochurlaud
– ochurlaud, Commented Sep 18, 2014 at 10:02

ochurlaud · Accepted Answer · 2014-09-14 23:48:04Z

Your first test does $people->fetch(). If the answer is not false, then it does it again and execute the code in the loop until the last element. So your if is the problem because it pass the first element while doing the test.

To solve this, just remove your if-condition: if the query doesn't find any people,

while( $people->fetch() ) { Do_something(); }

...will be jumped and everything will work as expected.

To add the error message, use a try/catch or check whether you entered the loop or not with a boolean (maybe there are other methods, though).

Not a try/catch, because it wouldn't throw an exception (it would return false). Instead, just call fetchAll() once and test the count() of the resultant array. If it's zero, show the error, if it's nonzero, do a foreach over the array to output data.

RobbieP · Accepted Answer · 2014-09-15 00:00:37Z

Change the conditional to test against the result

$people->execute(); $people->store_result(); $people->bind_result($id, $name); if($people->num_rows == 0) { echo "Invalid School Name!!"; } else { while($people->fetch()) { echo 'ID. ',$id, ' ',$name,'<br>'; } }

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