MySQL 8.0

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CREATE TABLE sales( ID INT, date DATE, Color VARCHAR(50), IUSERQ VARCHAR(50));

INSERT INTO sales VALUES
(1,'2020-09-25 18:55:54','RED','GGW3'),
(2,'2020-09-25 18:24:12','RED','FFQ3'),
(3,'2020-09-24 17:32:52','RED','GWW3'),
(4,'2020-09-23 17:42:37','BLUE','JJN6'),
(5,'2020-09-23 17:33:55','BLUE','VVV5'),
(6,'2020-09-23 18:53:57','RED','FFQ3'),
(7,'2020-09-22 18:15:11','BLUE','FFQ3');
SET @sql = NULL;

SELECT GROUP_CONCAT(
             DISTINCT
             CONCAT(
                    'SUM( color =''', color, ''' ) AS ',color
                    )
       )
  INTO @sql
  FROM sales s;

SET @sql = CONCAT('SELECT WEEK(date) AS WEEK,',@sql,
                   ' FROM sales
                    WHERE YEAR(date) = YEAR(NOW()) 
                    GROUP BY WEEK
                    ORDER BY WEEK'); 


-- add to php code : if($stmt = $link->query( @sql ")){ ....

-- the below part is just for showing the result set for the query

PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;


WEEK
BLUE
RED


38
3
4


INSERT INTO sales VALUES
(8,'2020-09-25 18:55:54','GREEN','TTW3'),
(9,'2020-09-25 18:24:12','GREEN','YYP4');
SET @sql = NULL;

SELECT GROUP_CONCAT(
             DISTINCT
             CONCAT(
                    'SUM( color =''', color, ''' ) AS ',color
                    )
       )
  INTO @sql
  FROM sales s;

SET @sql = CONCAT('SELECT WEEK(date) AS WEEK,',@sql,
                   ' FROM sales
                    WHERE YEAR(date) = YEAR(NOW()) 
                    GROUP BY WEEK
                    ORDER BY WEEK'); 

PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;


WEEK
BLUE
GREEN
RED


38
3
2
4