Unknown column when using CASE in MySQL query

After 14 years,  my 300th question...

Please see this MySQL query

CREATE TEMPORARY TABLE scores AS
SELECT * FROM
(
SELECT home_team AS Team, home_score AS f_score, away_score AS a_score, match_date,
       CASE 
            WHEN home_score > away_score THEN 'W'  
            WHEN home_score < away_score THEN 'L' 
            ELSE 'D' 
       END AS wdl
    FROM all_results
    WHERE ar_fobg_team_code = '1'
    AND ar_season_start = 2017
    AND home_score REGEXP '[[:digit:]]'
        UNION
    SELECT away_team AS Team, away_score AS f_score, home_score AS a_score, match_date,
       CASE wdl
            WHEN home_score > away_score THEN 'L'  
            WHEN home_score < away_score THEN 'W' 
            ELSE 'D' 
       END AS wdl
    FROM all_results
    WHERE ar_fobg_team_code = '1'
    AND ar_season_start = 2017
    AND home_score REGEXP '[[:digit:]]'
) AS the_data;

Select allOpen in new window

When I run it I get an error 1054 Unknown column 'wdl' in field list.

My immediate response is...Of course it doesn't exist, I'm trying to create it!

What am I missing?