How to record this value in mysql database? - php

Question

I have a data that looks like this
"discountPrices": [
{
"startQuantity": 3,
"price": 65.0
},
{
"startQuantity": 8,
"price": 62.0
},
{
"startQuantity": 20,
"price": 60.0
},
]
As you know, this is a discount price of a product. I am trying to achieve two things here.
1.) I want to create a table called discountprice and the table will have columns namely price | minqty | maxqty. Using the data above, the first row will be 65.00 | 3 | 7 , and the second row will be 62.00 | 8 | 19 and the third row will be 60 | 20 | 1000.
The issue I am first here is that I don't know how to get the maximum qty because the data did not contain the maximum quantity. It only states the startQuantity. How can I get the Maxquanity for each of the row and record it?
2.) How can I output it on a page. For example, using the data, I can do something like 3>=7 = $65.00, 8>=19 = $62.00 , 20>=1000 = $60.00
I think the hardest part is how to know the maximum quantity since it is not specified. Please how can I achieve this result.

Answer 1

You don't need to know the max qty. Just store your data as is and query for the first row that has a startQuantity less than or equal to your orderQuantity:
SELECT price FROM discounts
WHERE startQuantity <= :orderQuantity
ORDER BY startQuantity DESC
LIMIT 1
See here for example.
If you don't find a result, then there's no discount and your price is just the base undiscounted price. (Or you could insert a row with the base price and 0 for startQuantity.)
Note, I assume you're selling more than one product, so you'll likely need a field in that table (and the associated WHERE clause) to identify which product.

Answer 2

You can use the following code snnipt to get the max quantity
$json = '[
{
"startQuantity":3,
"price":65.0
},
{
"startQuantity":8,
"price":62.0
},
{
"startQuantity":20,
"price":60.0
}
]';
$jsonToArray = json_decode($json, true);
$startQuantity = array_column($jsonToArray, 'startQuantity');
array_walk($jsonToArray, function($v, $k) use (&$jsonToArray, $startQuantity) {
$index = array_search($v['startQuantity'], $startQuantity);
if(array_key_exists($index+1, $startQuantity))
$jsonToArray[$k]['endQuantity'] = $startQuantity[$index+1]-1;
});
print_r($jsonToArray);
Result
Array
(
[0] => Array
(
[startQuantity] => 3
[price] => 65
[endQuantity] => 7
)
[1] => Array
(
[startQuantity] => 8
[price] => 62
[endQuantity] => 19
)
[2] => Array
(
[startQuantity] => 20
[price] => 60
)
)