Question

In order for two queries to be UNION-compatible, they must: Select one: A. both have the same number of lines in their SQL statements. B. both output compatible data types for each column and return the same number of rows. C. both return at least one row. D. both return exactly one row.

Answer 1

Answer: B. both output compatible data types for each column and return the same number of rows.

Explanation:

In order for two queries to be UNION-compatible, they must be both output compatible data types for each column and return the same number of rows.

It should be noted that two relations are union compatible when both relations have the same attributes and also the domain regarding the identical attributes are thesame.