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071考試-第34題、choose two
Which two statements are true regarding operators used with subqueries? (Choose two.)
A) =ANY and =ALL operators have the same functionality.
E) The NOT IN operator is equivalent to is NULL.
C) The
D) The NOT operator can be used with IN, ANY and ALL operators.
E) The IN operator cannot be used in single-row subqueries.
Answer:CD
(解析:051 曾經(jīng)出現(xiàn)過,但是當(dāng)時是單選題,答案是 D,這個語法比較少見。
其實就是把 NOT 放到整個表達式之前,下面條件執(zhí)行的結(jié)果都是一樣,考大家的邏輯思維能力:
WHERE NOT col IN (SELECT ...)(也可以是 WHERE col not IN (SELECT ...))
WHERE NOT col = ANY (SELECT ...)(大于、小于都可以)
WHERE NOT col = ALL (SELECT ...)(大于、小于都可以)
SQL> select deptno from emp
2 where not deptno in (select deptno from dept where deptno=10);
DEPTNO
----------
20
30
30
....
或者:
select deptno from emp
where not deptno = all (select deptno from dept where deptno=10);