Aetna
Acquisita da CVS Health
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Domanda di colloquio di Aetna
Q: In SQL, what is the difference between a union, join and append?
Risposta di colloquio
Anonimo
1 nov 2017
A union creates a larger horizontal data set that may have no connection, a join relates two tables that are semantically connected by an index, an append simply adds the contents of one table to the end of another table.