我得到这个错误：
u“第2:34行在表达式规范的'order'附近缺少（'near'order'\n第2:41行输入不匹配'by'应为）在表达式规范的'order'附近
当我跑步时：

customer_cutoff3=sqlContext.sql("""
select category,
PERCENTILE_DISC(0.4) WITHIN GROUP (ORDER BY ty_spend) OVER (PARTITION BY category ) as low_spend_cutoff
from customer_cutoff2
where ty_visits>0
group by category
""").toPandas()

有人能帮我吗？