It appears what you need is a UNION instead of a LEFT Join.
Typically a workbook or data source helps others to understand the context of the issue you are facing.
Thanks for the response. The only two join options I am given is Inner or Left. What is the Union join you mentioned?
Even if I just have one sheets selected for my data source, before selecting another to join it to, the resulting table only displays 151 rows. Why only that amount?