Which three statements are true about a self join? (Choose three.)
Which three statements are true about a self join? (Choose three.)
A self join is simply a regular join but with the same table being joined. It can utilize an outer join, so it does not necessarily have to be an inner join. The ON clause can be used, though it is not mandatory as other join conditions like USING can also be employed. Additionally, to differentiate the same table being referenced twice, the query must use two different aliases for the table.
DEF for me
DEF, D says CAN
It can never be an outer JOIN though, because you are JOINing Data with itsself it will always be as if you would use INTERSECT as all Data of 1 Table exists in the other. Therefore it must be an inner JOIN. Also regarding F, you can just give one of the tables an alias, the other one does not need one, while both have different names then, they technically do not have different aliases, which leads me to choose C and E. The rest seems wrong to me.
not sure why ain't like this