Hello, Quick question about Joins in Flink SQL: I have a query where I write a simple left join. I noticed that the preview of changes is different when I add the keyword

outer

! To my understanding, the

outer

keyword is superfluous and should not change the result of the join. Am I missing something?

with t1 AS (
select 
  ...
from `table1` t1
),
t2 AS (
select
  ...
from `table1` t2
)
select 
  *
FROM t1
left [OUTER] join t2
ON t1.accountId = t2.accountId 
AND t1.id = t2.id

The change contains only the

create

operation when using the

outer

, whereas it contains

create

-

delete

-

create

in a simple left join (with null on the second part of the data

Left outer joins are documented at https://nightlies.apache.org/flink/flink-docs-master/docs/dev/table/sql/queries/joins/#left-outer-join - Left joins and left outer joins work differently when it comes to empty results