Merge Method	Description	Note
Inner Join	Keeps only rows where ‘key variable’ matches in both data sets
Outer Join	Keeps all rows from both datasets, adding NaN or nulls where no match is found.
Partial Outer Join	Keep all rows from the data set with the highest priority and add matched rows from the second data set.	You must specify the data sources to include.
Anti-Join	Adds rows with non-matching key value from the data sources to the new data source