“Map”将无法在“纯Pig”中执行类似操作。因此你需要一个自定义项。我不确定您想要得到什么作为join的输出，但是根据您的需要调整python udf应该相当容易。
myudf.py公司

@outputSchema('cols: {(col:chararray)}')
def join_maps(M1, M2):
    # This literally returns all column names that exist in both maps.
    out = []
    for k,v in M1.iteritems():
        if k in M2 and v is not None and M2[k] is not None:
            out.append(k)
    return out

你可以像这样使用它：

register 'myudf.py' using jython as myudf ;

# We can call sub2 from in sub1 since it only has one row

D = FOREACH sub1 GENERATE myudf.join_maps(b_c, sub2.b_c) ;