SQL查询中缺少运算符

Question

我正在尝试从MS Access查询棒球数据库，但我的SQL语句一直停留在丢失的运算符上。下面是我传递的SQL查询：

SELECT 
    Master.nameFirst, Master.nameLast, 
    Master.nameFirst + ' ' + Master.nameLast as FULLNAME, 
    (SUM(Batting.H) + SUM(Batting.BB) + SUM(Batting.HBP)) / (SUM(Batting.AB) + SUM(Batting.BB) + SUM(Batting.HBP)) as OBP, 
    SUM(Batting.H) / (SUM(Batting.H) + SUM(Batting.BB) + SUM(Batting.HBP)) as HitP, 
    (SUM(Batting.2B) + SUM(Batting.3B) + SUM(Batting.HR)) / SUM(Batting.H) as ExtraP, 
    SUM(Batting.HR) / (SUM(Batting.2B) + SUM(Batting.3B) + SUM(Batting.HR)) as HRP, 
    SUM(Batting.3B) / (SUM(Batting.2B) + SUM(Batting.3B)) as TriplePerc, 
    SUM(Batting.HBP) / (SUM(Batting.BB) + SUM(Batting.HBP)) as HBPP 
FROM 
    Master 
INNER JOIN 
    Batting ON Master.playerID = Batting.playerID 
WHERE
    (Batting.playerID IN (SELECT playerID 
                          FROM Master 
                          WHERE (nameFirst = 'Ryan' AND nameLast = 'Howard'))

缺少的操作符错误似乎集中在这个单一表达式上：

(SUM(Batting.2B) + SUM(Batting.3B) + SUM(Batting.HR)) / SUM(Batting.H) as ExtraP

但老实说，我没有看到任何错误。我错过了什么？