Single select statement error "Every derived table must have its own alias"

Question

I've been trying to get the following select statement to work for a few days now but haven't had any luck. A quick summary of the code is that it returns a list of all teams in the database and how many wins each team has against teams ranked in the top 10. The wins are pulled from the games table which contains every game that has been played. Here is the code I have

SELECT     IF(@last_ranking <> formula, @current_rankings := @current_rankings + 1, @current_rankings)  AS rank, 
            @last_ranking := formula, 
            prequery.team, 
            prequery.formula
FROM        (select @current_rankings := 0) sqlvars, 
            (SELECT    team, 
                        SUM(score) formula 
            FROM (SELECT     g.home_team, 
                            SUM(CASE WHEN t.team_id IS NULL THEN 0 ELSE g.home_wins END) AS formula 
            FROM            games g LEFT JOIN 
                        _top_10 AS t ON g.away_team = t.team_id 
            WHERE       
                        g.season = 2012 AND 
                        g.completed = 1 
        UNION ALL SELECT     g.away_team, 
                        SUM(CASE WHEN t2.team_id IS NULL THEN 0 ELSE g.away_wins END) AS formula 
            FROM        games g LEFT JOIN 
                        _top_10 AS t2 ON g.home_team = t2.team_id 
            WHERE      
                        g.season = 2012 AND 
                        g.completed = 1), 
                            (SELECT @current_rankings := 0, @last_ranking := 0) r 
                GROUP BY team ORDER BY formula DESC ) prequery;

but I keep getting the following error

Error Code: 1248. Every derived table must have its own alias

Can anyone see what I'm doing wrong here. Thanks!

Answer 1

probably you miss to add the alias because of the alignment of your SELECT statements.

SELECT  IF(@last_ranking <> formula, @current_rankings := @current_rankings + 1, @current_rankings)  AS rank, 
        @last_ranking := formula, 
        prequery.team, 
        prequery.formula
FROM    (select @current_rankings := 0) sqlvars, 
        (
            SELECT  team, 
                    SUM(score) formula 
            FROM    (
                        SELECT  g.home_team, 
                                SUM(CASE WHEN t.team_id IS NULL THEN 0 ELSE g.home_wins END) AS formula 
                        FROM    games g LEFT JOIN 
                                _top_10 AS t ON g.away_team = t.team_id 
                        WHERE   g.season = 2012 AND 
                                g.completed = 1 
                        UNION ALL 
                        SELECT      g.away_team, 
                                    SUM(CASE WHEN t2.team_id IS NULL THEN 0 ELSE g.away_wins END) AS formula 
                        FROM        games g LEFT JOIN 
                                    _top_10 AS t2 ON g.home_team = t2.team_id 
                        WHERE      
                                    g.season = 2012 AND 
                                    g.completed = 1
                    ) AS AliasHere,  -- <<=== HERE
                    (SELECT @current_rankings := 0, @last_ranking := 0) r 
                GROUP BY team ORDER BY formula DESC 
        ) prequery;