Which statement is true about the INTERSECT operator used in compound queries?
Which statement is true about the INTERSECT operator used in compound queries?
The INTERSECT operator returns only the rows that appear in both result sets, including NULL values. NULLs are processed and can be part of the result if they are present in both result sets. The other statements are incorrect: you can have multiple INTERSECT operators in the same SQL statement, INTERSECT has the same precedence as UNION and UNION ALL, and it does not ignore NULLs.
B. SET operators all have the same priority in Oracle Database. NULL values are processed with set operators
i agree
SELECT 1, 2 FROM DUAL UNION SELECT 2, 3 FROM DUAL INTERSECT SELECT NULL, NULL FROM DUAL INTERSECT SELECT NULL, NULL FROM DUAL; returns "no data found".
That is expected: the second two selects have no values in common with the corresponding columns in the first two, and the first two have nothing in common between them. For any row to be returned, with NULL values or not, it should be present in all of the intersected tables.
agree, answer should be B
B is right.
正しいです。
Quotations originate in official Oracle Database 19c documentation. A – false; following query is executed successfully: SELECT empno FROM history WHERE beginyear <= 1995 INTERSECT SELECT empno FROM employees WHERE job='TRAINER' INTERSECT SELECT trainer FROM offerings WHERE location <> 'SEATTLE'; B – true; “The INTERSECT operator with the keyword ALL returns the result of two or more SELECT statements in which rows appear in all result sets. Null values that are common across the component queries of INTERSECT ALL are returned at the end of the result set.” C – false; “You can combine multiple queries using the set operators UNION, UNION ALL, INTERSECT, INTERSECT ALL, EXCEPT, EXCEPT ALL, MINUS, and MINUS ALL. All set operators have equal precedence.” D – false; see answer B
Provided answer is correct.
In IZO-082 exam topic, aren't there SQL fudatmental? right
B 100%
SET operators process NULL values
B is correct
B is correct
B is correct