如何在 MYSQL 中获取过去 30 天的数据并使用 php 中的变量在循环内打印过去 30 天

Question

I need to get past 30 days sales records from MYSQL database to display in a bar chart how many items sold each day. Also I need to display past 30 days in my chart x axis in my php document. I tried run this code inside a for loop. because I am running some other codes to display some data using this loop. Take a look at the following code and help me how to achieve this. This is the table I try to get data from

Date format (YYYY-MM-DD)

Products Table

product_id | sold_by | qty | added_date  | sold_date
-----------+---------+-----+-------------+-----------
3          | 12      | 7   | 2022-05-05  | 2022-07-28
3          | 12      | 7   | 2022-05-05  | 2022-07-29
3          | 12      | 7   | 2022-05-05  | 2022-07-30
3          | 12      | 1   | 2022-05-05  | 2022-07-30
3          | 12      | 2   | 2022-05-05  | 2022-07-30
6          | 22      | 4   | 2022-06-06  | 2022-07-31
8          | 11      | 6   | 2022-08-05  | 2022-07-31



Deleted Table

product_id | added_date  | delete_date
-----------+-------------+-----------
3          | 2022-05-05  | 2022-07-28
3          | 2022-05-05  | 2022-07-29
3          | 2022-05-05  | 2022-07-30
3          | 2022-05-05  | 2022-07-30
3          | 2022-05-05  | 2022-07-30
6          | 2022-06-06  | 2022-07-31
8          | 2022-08-05  | 2022-07-31

As you can see for some days I have multiple records.

<?php
//for loop to run 30 times to get 30 days results
for ($i = 30; $i >= 0; $i--) {
   $sold_products_count = mysqli_num_rows(mysqli_query($conn, "SELECT * FROM products WHERE sold_date = CURRENT_DATE - $i"));
   $deleted_count = mysqli_num_rows(mysqli_query($conn, "SELECT * FROM deleted WHERE delete_date = CURRENT_DATE - $i"));
?> 
{
<?php
   $current_date = date("Y-m-d");
   $new_date = date_create($current_date);
   date_sub($new_date, date_interval_create_from_date_string("$i day"));
?>
   x: '<?php echo date_format($new_date, "Y-m-d"); ?>',
   a: <?php echo $deleted_count; ?>,
   s: <?php echo $sold_products_count; ?>,
},
<?php
}
?>

x- X axis data in the chart a - number of products deleted in specific date s - number of products sold in specific date

With the above code I was able to print the x axis data. I am not sure how to get past 30 days data from the SQL database. I think the problem is in the $i part in the SQL query.

Answer 1

In your query, if you use INTERVAL , you can use some days for adding/reducing from the current or specific date. For example in your case, if you always want to get the last 30 days data, you can use your WHERE like this:

sold_date >= CURDATE() - INTERVAL 30 DAY