Wordpress $ wpbd-> get_results即使是空的也会返回日期

Question

I have a table looks like:

id | date       | count  
-----------------------
1  | 2016-07-13 | 2  
2  | 2016-07-13 | 3  
3  | 2016-07-13 | 1  
4  | 2016-07-15 | 12  
5  | 2016-07-15 | 1  
6  | 2016-07-15 | 4

This is my query

$test_query = $wpdb->get_results("
  SELECT 
    SUM(count) AS count, 
    date 
  FROM 
    ".$wpdb->prefix."statistics 
  WHERE 
    date BETWEEN DATE_SUB('2016-07-15', INTERVAL 2 DAY) AND '2016-07-15' 
  GROUP BY DATE(date)
");

I run the query to get the results

2016-07-13 | 6
2016-07-15 | 17

This working good, only I have a interval for 3 days and the results from the date 2016-07-14 is not showing up. I use a chart where the value needs to be empty or 0.

Is there a way that 2016-07-14 value is 0?

2016-07-13 | 6
2016-07-14 | 0
2016-07-15 | 17

Answer 1

I have found a solution. I've got a startdate and a enddate. With a for loop, I get all the dates between them. Then I compare them with the date in the database.

Thank you all for the reactions!