Computer Architecture > QUESTIONS & ANSWERS > CSE 385 Databases - Miami University_ Assignment Day2 –SQL: Comprehensive Exam. Q&A (All)

CSE 385 Databases - Miami University_ Assignment Day2 –SQL: Comprehensive Exam. Q&A

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Answer 1. What is a result set? A set of rows from a database 2. What is the difference between Union and Union All? Union All returns all duplicate records, Union removes duplicate records . Uni ... on column sorts the data, Union All can’t 3. What are the other Set Operators SQL Server has? Exclude union and union all, there are intersect and minus. 4. What is the difference between Union and Join? Join combine data into new columns, but unions combine data into new rows. 5. What is the difference between INNER JOIN and FULL JOIN? Inner join returns only matched row, but full join returns rows from both tables even if there are no matching rows in the other table. 6. What is difference between left join and outer join Outer join compares two tables and returns data when a match is available or NULL values otherwise. But left join keep all records from left table no mater what and insert NULL values when right table doesn’t match. 7. What is cross join? Cross Join compares two tables and return every possible combination of rows from the two tables. 8. What is self join? Self join is a query in which a table is compared to itself. 9. What is the difference between WHERE clause and HAVING clause? Having clause should be used with Group by statements. But where clause cannot be used with aggregates. 10. Can there be multiple group by columns? Yes. [Show More]

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