| 1. | The SQL database language includes statements for: |
| a. | Database definition. |
| b. | Database manipulation. |
| c. | Database control. |
| d. | All of the above. |
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Answer: (d).All of the above.
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| 2. | A command to remove a relation from an SQL database |
| a. | Delete table table name |
| b. | Drop table table name |
| c. | Erase table table name |
| d. | Alter table table name |
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Answer: (b).Drop table table name
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| 3. | Which SQL Query is use to remove a table and all its data from the database? |
| a. | Create Table |
| b. | Alter Table |
| c. | Drop Table |
| d. | None of these |
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Answer: (c).Drop Table
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| 4. | A type of query that is placed within a WHERE or HAVING clause of another query is called |
| a. | Super query |
| b. | Sub query |
| c. | Master query |
| d. | Multi-query |
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Answer: (b).Sub query
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| 5. | Aggregate functions are functions that take a ___________ as input and return a single value. |
| a. | Collection of values |
| b. | Single value |
| c. | Aggregate value |
| d. | Both a & b |
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Answer: (a).Collection of values
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| 6. | Select __________ from instructor where dept name= ’Comp. Sci.’; Which of the following should be used to find the mean of the salary ? |
| a. | Mean(salary) |
| b. | Avg(salary) |
| c. | Sum(salary) |
| d. | Count(salary) |
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Answer: (b).Avg(salary)
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| 7. | All aggregate functions except _____ ignore null values in their input collection. |
| a. | Count(attribute) |
| b. | Count(*) |
| c. | Avg |
| d. | Sum |
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Answer: (b).Count(*)
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| 8. | A Boolean data type that can take values true, false, and________ . |
| a. | 1 |
| b. | 0 |
| c. | Null |
| d. | Unknown |
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Answer: (d).Unknown
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| 9. | Select count (____ ID) from teaches where semester = ’Spring’ and year = 2010; If we do want to eliminate duplicates, we use the keyword ______in the aggregate expression. |
| a. | Distinct |
| b. | Count |
| c. | Avg |
| d. | Primary key |
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Answer: (a).Distinct
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| 10. | The ____ connective tests for set membership, where the set is a collection of values produced by a select clause. The ____ connective tests for the absence of set membership. |
| a. | Or, in |
| b. | Not in, in |
| c. | In, not in |
| d. | In, or |
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Answer: (c).In, not in
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