PHP Query - Exclude if exist in table - php

Question

orderfood
orderfood_id food_id total_amount
foodcancel
foodcancel_id food_id status
$query = $this->db->query("SELECT * FROM order_food of LEFT JOIN `foodcancel` fc ON of.food_id = fc.food_id WHERE of.orderfood_id = '" . (int)$orderfood_id . "'");
$order_foods = $query->rows;
above is my query, what i wanted is that if there food_id inside foodcancel table , exclude it from rows, possbile to do it ?

Answer 1

For exclude the existing values you could try checking null for corresponding matching value
SELECT *
FROM order_food of
LEFT JOIN foodcancel fc ON of.food_id = fc.food_id
and of.food_id = your_value
WHERE fc.orderfood_id is null
anyway you should not php var in your sql code because in this way you are are risk for sqlinjection for avoid this you should take a look at prepared statement and binding param

Answer 2

It's very possible to do. In my logic. first, you must get all food_id on food_cancel table. Then save it into variabel and use it when you show orderFood table with adding NOT IN condition.
I've write code for you,
<?php
// Get Food Id From Cancel
$orderCancel = mysqli_query($mysqli, "SELECT * FROM `foodcancel`");
$cancelId = "";
while ($cancel = mysqli_fetch_array($orderCancel)) {
$cancelId .= $cancel["food_id"].",";
};
$cancelId = substr($cancelId, 0, -1);
// Put Food Id on Cancel Table into NOT IN Condition Database
$orderFood = mysqli_query($mysqli, "SELECT * FROM `orderfood` WHERE food_id NOT IN ($cancelId)");
while ($order = mysqli_fetch_assoc($orderFood)) {
$food[] = $order;
};
echo json_encode($food);
?>