[英]How to get the list of all columns having NULL values only in hive?
I am working on a huge data set having more than 10k rows and more than 600 columns in Hive .我正在处理一个庞大的数据集,在Hive中有超过 10k 行和超过 600 列。 There are multiple rows columns which having NULL
value for all the rows.有多个行列,所有行的NULL
值。 How can I get the list of all the columns having only NULL
values?如何获取只有NULL
值的所有列的列表?
Use count(col)
to count all NOT NULL
rows for some column.使用count(col)
计算某些列的所有NOT NULL
行。
Columns with all NULL
s will have 0
counts:所有NULL
的列将有0
个计数:
select
count(col1) as col1_cnt,
count(col2) as col2_cnt,
...
count(colN) as colN_cnt
from table
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