SQL – Creating Other Schema Objects Questions 1. Which database object among the following provides a layer of abstraction between the users and the data? Table Rows Views Synonyms Answer: C, D. Views and Synonyms do not store data themselves. A view is a temporary or virtual table used to retrieve data stored in underlying […]
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SQL – Using the Set Operators Questions 1.Which SET operator does the following figure indicate? UNION UNION ALL INTERSECT MINUS Answer: A. Set operators are used to combine the results of two (or more) SELECT statements.Valid set operators in Oracle 11g are UNION, UNION ALL, INTERSECT, and MINUS. When used with two SELECT statements, the […]
SQL – Subqueries to Solve Queries Questions 1. Which of the following are the types of sub-queries? Ordered sub-queries Grouped sub-queries Single row sub-queries None of the above Answer: C. A subquery is a complete query nested in the SELECT,FROM, HAVING, or WHERE clause of another query.The subquery must be enclosed in parentheses and have […]