Hi All:
Here I got two tables:
Table A
name
|
num
|
tom
|
2
|
jerry
|
3
|
jerry
|
4
|
null
|
null
|
Table B
name
|
score
|
tom
|
12
|
jerry
|
10
|
jerry
|
8
|
null
|
null
|
When i use spark.sql() to get result from A and B with sql :
select
a.name as aName,
a.date,
b.name as bName
from
(
select
name,
date_format(now(),'yyyy-MM-dd') AS date
from
A
group by
name
) a
FULL JOIN
(
select
name
from
B
group by
name
) b
ON a.name = b.name
I got results contain ALL
NULL VALUE ROW like:
aName
|
date
|
bName
|
null
|
null
|
null
|
…
|
…
|
…
|
Can anyone explains why all
null value row appears?