Introduction to SQL – General Questions

16. In an SQL SELECT statement querying a single table, according to the SQL-92 standard the asterisk (*) means that:

A. all columns of the table are to be returned.
B. all records meeting the full criteria are to be returned.
C. all records with even partial criteria met are to be returned.
D. None of the above is correct.

Correct Answer:  A. all columns of the table are to be returned.

17. The HAVING clause does which of the following?

A. Acts like a WHERE clause but is used for groups rather than rows.
B. Acts like a WHERE clause but is used for rows rather than columns.
C. Acts like a WHERE clause but is used for columns rather than groups.
D. Acts EXACTLY like a WHERE clause.

Correct Answer:  A. Acts like a WHERE clause but is used for groups rather than rows.

18. The SQL -92 wildcards are ____ and ____ .

A. asterisk (*); percent sign (%)
B. percent sign (%); underscore (_)
C. underscore(_); question mark (?)
D. questio n mark (?); asterisk (*)

Correct Answer:  B. percent sign (%); underscore (_)

19. To remove duplicate rows from the results of an SQL SELECT statement, the ________ qualifier specified must be included.

A. ONLY
B. UNIQUE
C. DISTINCT
D. SINGLE

Correct Answer:  C. DISTINCT

20. The benefits of a standard relational language include which of the following?

A. Reduced training costs
B. Increased dependence on a single vendor
C. Applications are not needed.
D. All of the above.

Correct Answer:  A. Reduced training costs

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