你可以数数 Score Windows上方 ID ，然后打开过滤器 Score 不为null或计数为0：

from pyspark.sql import Window
from pyspark.sql import functions as F
df1 = df.withColumn(
    "count_scores",
    F.count("Score").over(Window.partitionBy("ID"))
).where("Score IS NOT NULL OR count_scores = 0")\
 .drop("count_scores")
df1.show()
# +---+-----+
# | ID|Score|
# +---+-----+
# |BBB| null|
# |AAA| High|
# |AAA|  Mid|
# +---+-----+

您可以添加是否所有分数都为空的标志，并过滤分数不为空或标志为真（所有分数都为空）时的行：

from pyspark.sql import functions as F, Window
df2 = df.withColumn(
    'flag', 
    F.min(F.col('Score').isNull()).over(Window.partitionBy('ID'))
).filter('flag or Score is not null').drop('flag')
df2.show()
+---+-----+
| ID|Score|
+---+-----+
|BBB| null|
|AAA| High|
|AAA|  Mid|
+---+-----+