Finding nearest value in a mysqli array php - php

Question

In my app, the user can enter a number for pricing and based on the input, the database will return a plan with the same price. If there is no number/price corresponding to the user input, I would like the program to find the plan with the nearest value. How can I find the "nearest" value in a haystack?
Examples :
User inputs : $14, Returns the 15$ plan
User inputs : $20, Returns the 15$ plan
User inputs : 25$. Returns the 30$ plan
Etc...
This is what I have :
//Create pricing for each plan
$getplansql = "SELECT SUM(`Distributor Net Price`) AS dnetprice FROM `services` wspn
WHERE wspn.planName = '$planname_num[$pn]' AND wspn.planLevel = '$planlevels_num[$pl]'";
$resultplans = $conn->query($getplansql);
while($plan = mysqli_fetch_assoc($resultplans)) {// output data of each row
$inhousepricing = ($plan['dnetprice'] * 0.15) + ($plan['dnetprice']);
$finalpricing = round($inhousepricing);
if($planprice == $finalpricing) {//found matching row// there's a plan with that price
//put plan info in array
$planArray = array(
'planName' => $plan['name'],
'planPrice' => $finalpricing,
'planDescription' => $plan['description']
);
break;//stop statement and only get the first plan//row found
}else{//get the plan with the nearest value
//put plan info in array
}

Answer 1

Add 15% and find the closest price in the SQL query itself.
$getplansql = "name, description, dnetprice
FROM (
SELECT planName AS name, planDescription AS description, ROUND(SUM(`Distributor Net Price`) * 1.15) AS dnetprice
FROM `services` wspn
WHERE wspn.planName = '$planname_num[$pn]' AND wspn.planLevel = '$planlevels_num[$pl]'
) AS x
ORDER BY ABS(dnetprice - $planprice)
LIMIT 1";
$resultplans = $conn->query($getplansql);
$planArray = mysqli_fetch_assoc($resultplans);
This will just return the one row that you want, so you don't need a while loop.