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047-272

原创 Linux操作系统 作者:jbymy2000 时间:2012-03-19 14:37:24 0 删除 编辑
272. Which two statements are true regarding subqueries? (Choose two.)
A. The ORDER BY clause can be used in the subquery.
B. A subquery can be used in the FROM clause of a SELECT statement.
C. If the subquery returns NULL, the main query may still return result rows.
D. A subquery can be placed in a WHERE clause, GROUP BY clause, or a HAVING
clause.
E. Logical operators, such as AND, OR and NOT, cannot be used in the WHERE
clause of a subquery.
Answer: AB

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