你想找到一年中在最多球队效力的球员。因此，你应该按球员和年份分组，然后你可以计算每个球员每年的球队数量。最后，按计数降序排列数据-第一个结果就是你的答案。无需加载两次数据或执行联接。

batters = LOAD 'hdfs:/user/maria_dev/pigtest/Batting.csv' USING PigStorage(',') AS
    (id:chararray, yearid:int, teamid:chararray);

-- Apply filtering as needed here

teams_per_year = FOREACH (GROUP batters BY (id, yearid))
    GENERATE
    group.id AS id,
    group.yearid AS yearid,
    COUNT(batters.teamid) AS num_teams;

ordered_results = ORDER teams_per_year BY num_teams DESC;

DUMP ordered_results;

如果需要不同数量的团队，请添加嵌套的 DISTINCT :

teams_per_year = FOREACH (GROUP batters BY (id, yearid)) {
    dist_teams = DISTINCT batters.teamid;
    GENERATE
    group.id AS id,
    group.yearid AS yearid,
    COUNT(dist_teams) AS num_teams;
}