Join Function in ETL
I am trying to join a table on my DataSet, using the left join function. My original DataSet contains only 118k rows, and the other table contains 1405 rows. I thought that the output DataSet will stay 118k rows, and just have addition columns on it. However, the output DataSet is 4.6M which is way more then I expected. I am not sure if I misunderstand the join function. I want to use this function to add another column on my original DataSet by the matching primary key.