Do a 'left outer' join. This returns all rows in first CSV data set, including rows with no corresponding row in the second data set. When no corresponding row exists, it is padded out with empty fields.

Do a 'left anti' join. This returns all rows in first CSV data set that has no match with the second data set.

Do a 'left semi' join. This returns all rows in first CSV data set that has a match with the second data set.

Do a 'right outer' join. This returns all rows in second CSV data set, including rows with no corresponding row in the first data set. When no corresponding row exists, it is padded out with empty fields. (This is the reverse of 'outer left'.)

Do a 'full outer' join. This returns all rows in both data sets with matching records joined. If there is no match, the missing side will be padded out with empty fields. (This is the combination of 'outer left' and 'outer right'.)

USE WITH CAUTION. This returns the cartesian product of the CSV data sets given. The number of rows return is equal to N * M, where N and M correspond to the number of rows in the given data sets, respectively.

When set, joins will work on empty fields. Otherwise, empty fields are completely ignored. (In fact, any row that has an empty field in the key specified is ignored.)

The first row will be included in the count.

The field delimiter for reading CSV data. Must be a single character. (placeholder: ,)