topic Re: A right join returned more rows that were joined than actually read from the right table in SAS Data Management

A right join returned more rows that were joined than actually read from the right table

george7899 — Sat, 24 Aug 2019 21:33:03 GMT

Both the left and right tables have been standardized. There are 63 rows in the left table, and 31 rows in the right one.

A Data Join node (right join) was applied successfully. But the log shows there were 33 rows joined. Does it make sense to have 33 rows joined instead of 31?

Re: A right join returned more rows that were joined than actually read from the right table

Astounding — Sat, 24 Aug 2019 21:41:05 GMT

Things to consider ... perhaps ...

The left table contains a few records that match the same record in the right table
The joining provisions are not specific enough, so that the same record in the left table matches multiple records in the right table.

It's almost certainly a result of what's in the data, combined with the joining criteria.

Re: A right join returned more rows that were joined than actually read from the right table

novinosrin — Sat, 24 Aug 2019 21:43:36 GMT

A test to understand


data left;
do key_l=1 to 61;
 if key_l=31 then do _n_=1 to 3;
 output;
 end;
 else output;
end;
run;

data right;
 do key_r=1 to 31;
 output;
 end;
run;

proc sql;
create table w as
select *
from left  right join right 
on key_l=key_r;
quit;

Re: A right join returned more rows that were joined than actually read from the right table

george7899 — Tue, 27 Aug 2019 06:07:54 GMT

Yes, the left table does contain some records that match the same record in the right table.

Re: A right join returned more rows that were joined than actually read from the right table

george7899 — Tue, 27 Aug 2019 06:09:06 GMT

Thanks for your codes. very helpful!