MAMP - All MySQL Queries Return Null - php

Question

I recently installed MAMP. But my I can't successfully execute MySQL queries from php. I can connect to MySQL from php, but all my queries come back as NULL. I don't get any error message or other message that would help me diagnose the problem.
Oddly, I can successfully query MySQL with phpMyAdmin and MySQLWorkbench.
Here is my code:
<?php
$link = mysqli_init();
$con = mysqli_real_connect($link, 'localhost', 'root', 'root', 'mrmk', 8889);
$db = 'mrmk';
if (mysqli_connect_errno()) {
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
echo "Host information: " . mysqli_get_host_info($link) . PHP_EOL;
$sql = "SHOW TABLES FROM `$db`";
$result = mysqli_query($con, $sql);
echo "</br>" . "1. MySQL Error: " . mysqli_error();
echo "</br>" . "result: ";
var_dump($result);
$sql = "SHOW TABLES FROM $db";
$result = mysqli_query($con, $sql);
echo "</br></br>2. MySQL Error: " . mysqli_error();
echo "</br>" . "result: ";
var_dump($result);
$sql = "SELECT * FROM `transactionTable` WHERE `attorneyName` LIKE \'%howard%\'";
$result = mysqli_query($con, $sql);
echo "</br></br>3. MySQL Error: " . mysqli_error();
echo "</br>" . "result: ";
var_dump($result);
if (!$result) {
echo "</br></br>" . "4. MySQL Error: " . mysqli_error();
exit;
} else {
echo "we should have results.";
}
while ($row = mysqli_fetch_row($result)) {
echo "Table: {$row[0]}\n";
}
mysqli_free_result($result);
?>
When I access the page through localhost I get this:
Host information: Localhost via UNIX socket
1. MySQL Error:
result: NULL
2. MySQL Error:
result: NULL
3. MySQL Error:
result: NULL
4. MySQL Error:
When I execute the same queries from phpMyAdmin, they execute successfully and return non-NULL results.
I have two questions:
What code can I add to help diagnose this problem?
Do I have a error in my code that is causing me to get NULL results.

Answer 1

Have you enabled mysqli extension in PHP? Check apache error log. Look at this question for example. mysqli is disabled by default, you need to uncomment line
extension=php_mysqli
in php.ini file.

Answer 2

To answer question #1, you might find it helpful to echo your $sql variables, to make sure your queries are valid and what you intended them to be.