MySQL如何将两个JOINed表的SUM（）列转换为新列？

大家早上好/晚上好，

我正在尝试（LEFT）将两个表联接到一个表中，并SUM()匹配ON fk_id = id...语句的特定列的值。表格如下所示：

ws1表：

ws2表：

到目前为止我尝试过的查询：

SELECT
    alias.name alias,   
    (SUM(IFNULL(ws1.teamkills,0)) + SUM(IFNULL(ws2.teamkills,0))) teamkills
FROM pickup
    JOIN player ON player.pickup_id = pickup.id
    JOIN alias ON player.alias_id = alias.id
    LEFT JOIN weapon_stats_1 ws1 ON ws1.pickup_id = pickup.id AND ws1.player_id = player.id
    LEFT JOIN weapon_stats_2 ws2 ON ws2.pickup_id = pickup.id AND ws2.player_id = player.id
WHERE pickup.logfile_name = 'srv-20130725-2151-log' GROUP BY player.id

结果：

和：

SELECT
    alias.name alias,   
    (SUM(DISTINCT IFNULL(ws1.teamkills,0)) + SUM(DISTINCT IFNULL(ws2.teamkills,0))) teamkills
FROM pickup
    JOIN player ON player.pickup_id = pickup.id
    JOIN alias ON player.alias_id = alias.id
    LEFT JOIN weapon_stats_1 ws1 ON ws1.pickup_id = pickup.id AND ws1.player_id = player.id
    LEFT JOIN weapon_stats_2 ws2 ON ws2.pickup_id = pickup.id AND ws2.player_id = player.id
WHERE pickup.logfile_name = 'srv-20130725-2151-log' GROUP BY player.id

结果：

我了解SUM(DISTINCT.... )return 2，因为DISTINCT仅选择一个具有相同值的结果。

我的目标是获取SUM()两个teamkills字段的并将它们加在一起。在这个例子中，它应该返回3哪里player_id是4。我怎样才能做到这一点？

编辑：

表“玩家”：

表“提取”：