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Questions for Sql

Decent Essays

1. In Oracle, when is it better to use materialized views? A. It is always better to use materialized views because views are obsolete and materialized views replace them B. When a query is slow and its results need to be cached C. When the involved query is called many times from different places D. When there are many materials involved in the view E. Every time a view is slow 2. We have two tables, each with one column X of type number which is the primary key. Table A has 100 rows, Table B has 50 rows. When doing an Inner Join between A and B on X, which option would be correct? A. The maximum number of rows is 100, the minimum number of rows 50 B. The maximum number of rows is 5000, the minimum …show more content…

All of the above 10. What is the difference between UNION and UNION ALL commands? A. No difference, they are the same. UNION ALL is obsolete. B. UNION creates a union set of rows of two tables. UNION ALL does the same, but keeps only distinct rows. C. UNION ALL creates a union set of rows of two tables. UNION does the same, but keeps only distinct rows. D. UNION is faster than UNION ALL. E. UNION ALL is faster than

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