我有以下疑问：

SELECT col.myId,
                   SUM( CASE WHEN tu.userId IS NOT NULL THEN 1  ELSE 0 END) AS uCount,
                   SUM( CASE WHEN g.grouptype != 12 THEN 1  ELSE 0 END) AS gCount
            FROM myUserTable col
                     LEFT JOIN fooTable elem ON col.myId = elem.myId
                     LEFT JOIN barTable esc ON elem.anotherId = esc.anotherId
                     LEFT JOIN userTable tu ON esc.anotherId = tu.anotherId
                     LEFT JOIN grouTable g ON g.groupid = tu.groupid
            GROUP BY col.myId

这里的问题 userId 数到两次。我想避免它。
我怎样才能做到呢？