SQL Basic Interview Questions

1)  What does SQL stand for?

a) Strong Question Language

b) Structured Question Language

c)   Structured Query Language - correct answer

2) Which SQL statement is used to extract data from a database?

a) GET

b) OPEN

c) EXTRACT

d)   SELECT - correct answer

e) QUERY

3) Which SQL statement is used to update data in a database?

a)   UPDATE - correct answer

b) SAVE AS

c) MODIFY

d) SAVE

4) Which SQL statement is used to delete data from a database?

a) TRUNCATE

b)   DELETE - correct answer

c) REMOVE

5) Which SQL statement is used to insert new data in a database?

a) ADD RECORD

b) ADD INTO

c)   INSERT - correct answer

d) ADD NEW

6) With SQL, how do you select a column named "FirstName" from a table named "Persons"?

a) EXTRACT FirstName FROM Persons

b)   SELECT FirstName FROM Persons - correct answer

c) SELECT Persons.FirstName

7) With SQL, how do you select all the columns from a table named "Persons"?

a) SELECT [all] FROM Persons

b) SELECT All Persons

c) SELECT *.Persons

d)   SELECT * FROM Persons - correct answer

8) With SQL, how do you select all the records from a table named "Persons" where the value of the column "FirstName" is "Peter"?

a) SELECT [all] FROM Persons WHERE FirstName='Peter'

b) SELECT * FROM Persons WHERE FirstName LIKE 'Peter'

c) SELECT [all] FROM Persons WHERE FirstName LIKE 'Peter'

d)   SELECT * FROM Persons WHERE FirstName='Peter' - correct answer

9) With SQL, how do you select all the records from a table named "Persons" where the value of the column "FirstName" starts with an "a"?

a) SELECT * FROM Persons WHERE FirstName='%a%'

b) SELECT * FROM Persons WHERE FirstName LIKE '%a'

c) SELECT * FROM Persons WHERE FirstName='a'

d)   SELECT * FROM Persons WHERE FirstName LIKE 'a%' - correct answer

e) SELECT * FROM Persons WHERE FirstName='a'"

10) The OR operator displays a record if ANY conditions listed are true. The AND operator displays a record if ALL of the conditions listed are true

a)   True - correct answer

b) False

11) With SQL, how do you select all the records from a table named "Persons" where the "FirstName" is "Peter" and the "LastName" is "Jackson"?

a) SELECT * FROM Persons WHERE FirstName LIKE 'Peter' AND LastName LIKE 'Jackson'

b)   SELECT * FROM Persons WHERE FirstName='Peter' AND LastName='Jackson' - correct answer

c) SELECT FirstName='Peter', LastName='Jackson' FROM Persons

12) With SQL, how do you select all the records from a table named "Persons" where the "LastName" is alphabetically between (and including) "Hansen" and "Pettersen"?

a) SELECT LastName>'Hansen' AND LastName<'Pettersen' FROM Persons

b)   SELECT * FROM Persons WHERE LastName BETWEEN 'Hansen' AND 'Pettersen' - correct answer

c) SELECT * FROM Persons WHERE LastName>'Hansen' AND LastName<'Pettersen'

13) Which SQL statement is used to return only different values?

a) SELECT UNIQUE

b) SELECT INDENTITY

c) SELECT DIFFERENT

d)   SELECT DISTINCT - correct answer

14) Which SQL keyword is used to sort the result-set?

a)   SORT BY

b) ORDER

c) ORDER BY - correct answer

d) SORT

15) With SQL, how can you return all the records from a table named "Persons" sorted descending by "FirstName"?

a) SELECT * FROM Persons SORT BY 'FirstName' DESC

b)   SELECT * FROM Persons ORDER BY FirstName DESC - correct answer

c) SELECT * FROM Persons ORDER FirstName DESC

d) SELECT * FROM Persons SORT 'FirstName' DESC

16) With SQL, how can you insert a new record into the "Persons" table?

a)   INSERT INTO Persons VALUES ('Jimmy', 'Jackson') - correct answer

b) INSERT ('Jimmy', 'Jackson') INTO Persons

c) INSERT VALUES ('Jimmy', 'Jackson') INTO Persons

17) With SQL, how can you insert "Olsen" as the "LastName" in the "Persons" table?

a)    INSERT INTO Persons (LastName) VALUES ('Olsen') - correct answer

b) INSERT ('Olsen') INTO Persons (LastName)

c) INSERT INTO Persons ('Olsen') INTO LastName

18) How can you change "Hansen" into "Nilsen" in the "LastName" column in the Persons table?

a) UPDATE Persons SET LastName='Hansen' INTO LastName='Nilsen'

b)   UPDATE Persons SET LastName='Nilsen' WHERE LastName='Hansen' - correct answer

c) MODIFY Persons SET LastName='Hansen' INTO LastName='Nilsen

d) MODIFY Persons SET LastName='Nilsen' WHERE LastName='Hansen'

19) With SQL, how can you delete the records where the "FirstName" is "Peter" in the Persons Table?

a)   DELETE FROM Persons WHERE FirstName = 'Peter' - correct answer

b) DELETE ROW FirstName='Peter' FROM Persons

c) DELETE FirstName='Peter' FROM Persons

20) With SQL, how can you return the number of records in the "Persons" table?

a) SELECT COLUMNS() FROM Persons

b)   SELECT COUNT(*) FROM Persons - correct answer

c) SELECT COLUMNS(*) FROM Persons

d) SELECT COUNT() FROM Persons

21) Given an employees table as follows: empid name managerid a1 bob NULL b1 jim a1 B2 tom a1 What value will select count(*) from employees return?

a) 1

b) 2

c)   3 - correct answer

d) none of the above

22) The result of a SELECT statement can contain duplicate rows.

a)   True - correct answer

b) False

23) Sometimes the expression "select count(*)" will return fewer rows than the expression "select count(value)".

a) True

b)   False - correct answer

24) What type of lock will deny users any access to a table?

a) EXPLICIT

b) IMPLICIT

c) EXCLUSIVE - correct answer

d) SHARED

e)   READ ONLY

25) Which of the following is the correct SQL statement to use to remove rows from a table?

a)   DROP

b) REMOVE ROW

c) DELETE - correct answer

d) DELETE ROW

26) The only way to join two tables is by using standard, ANSI syntax.

a) True

b)   False - correct answer

27) A NULL value is treated as a blank or 0.

a) True

b)   False - correct answer

28) The left outer join is one type of outer join. Another one is the.

a) right

b) full

c) right outer

d) full outer

e)   all of the above - correct answer