Best Way to Represent Dates as Columns in Table

Have you tried using a Sumo card?  That is really the best way to pivot data in a visualization right now.

I ran into this issue in the opposite direction.  I had a data set with the months listed as separate columns and I needed a flat file.

I was able to find a dynamic SQL statement to collapse the columns regardless of how many dates there were.  Dynamic SQL is outside of my comfort zone, but I will share the code with you here to see if you can use it to help you "pivot" or uncollapse your data.

SELECT
GROUP_CONCAT(CONCAT('Select `Product Type`,',
QUOTE(COLUMN_NAME),
' AS `Date`, ',
'`',
COLUMN_NAME,
'` as `Revenue`',
'FROM original')
SEPARATOR ' UNION ALL ') AS product_info
FROM
INFORMATION_SCHEMA.COLUMNS
WHERE
TABLE_NAME = 'original'
AND COLUMN_NAME NOT IN ('Product Type');

CREATE PROCEDURE transpose()

BEGIN

SELECT product_info into @sql2 FROM for_transpose;

SET @str=concat('create table products as ',@sql2);

PREPARE q from @str;
EXECUTE q;

END

call transpose;

SELECT
`Product Type`,
STR_TO_DATE(REPLACE(`Date`, '/', ' '), '%m %d %Y') AS `Date`,
ROUND(`Revenue`, 2) AS `Revenue`
FROM
products
ORDER BY `Product Type` , `Date`

These steps essentially do the opposite of what you are looking for, but perhaps they will help you get to your answer.

Good luck