这可以使用sum（）或analytic sum（）实现，具体取决于单个表扫描中的确切要求。如果用户向购物车添加了两个产品，但只购买了一个呢？
对于用户+产品：

select userID, productID 
  from
(
select 
       userID,
       productID,
       sum(case when action='AddToCart' then 1 else 0 end) addToCart_cnt,
       sum(case when action='Purchase' then 1 else 0 end)  Purchase_cnt
  from table
  group by userID, productID
)s
where addToCart_cnt>0 and Purchase_cnt=0

配置单元：使用 not in ```
select * from table
where action='AddtoCart' and
userID not in (select distinct userID from table where action='Purchase')

pig：使用action过滤id并执行左连接，检查id是否为null

A = LOAD '\path\file.txt' USING PigStorage(',') AS (userID:int,b:int,c:int,action:chararray) -- Note I am assuming the first 3 columns are int.You will have to figure out the loading without the quotes.
B = FILTER A BY (action='AddToCart');
C = FILTER A BY (action='Purchase');
D = JOIN B BY userID LEFT OUTER,C BY userID;
E = FILTER D BY C.userID is null;
DUMP E;