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Test answers for SQL 2020

(127, CL) Last updated: February 28
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127 Answered Test Questions:

1. What is the typical filename extension of a SQL file?

Answers:

• .sequel

• .query

• .sql

• .dataquery

2. Which of the following is NOT an explicit data type reference?

Answers:

• character

• smallint

• null

• integer

• float

3. Which of these is not a language element of SQL?

Answers:

• Statements

• Clauses

• Queries

• None... all are language elements of SQL.

• Expressions

4. What keyword is used in conjunction with the INNER JOIN keywords to return rows when there is at least one match in both tables?

Answers:

• IN

• CONNECT

• ON

• WHEN

5. What is the term for a set of data elements (values) organized using rows and columns?

Answers:

• query

• program

• index

• table

6. Which clause indicates the table(s) from which data is to be retrieved?

Answers:

• HAVING

• SELECT

• FROM

• WHERE

• GROUP BY

7. Which statement can be used to repeat the execution of a code block as long as a specified condition returns TRUE?

Answers:

• SELECT statement

• SUBQUERY statement

• SIGNAL statement

• WHILE statement

• GOTO statement

8. Suppose table A has 5 rows and table B has 6 rows. You perform a cross join on these two tables. How many rows will it have?

Answers:

• 11

• 25

• 30

• 5

• 6

9. True or False? This query is valid the way it is structured.  SELECT * FROM Prospects WHERE assignment_type <> 'Team' AND criteria is not null

Answers:

• False

• True

10. Which symbol can be used to indicate a "wild card" to substitute for one or more characters when searching for string in a database?

Answers:

• @

• *

• #

• &

• %

11. How can you change "Hansen" into "Nilsen" in the "LastName" column in the Persons table?

Answers:

• UPDATE Persons SET LastName='Nilsen' WHERE LastName='Hansen'

• MODIFY Persons SET LastName='Nilsen' WHERE LastName='Hansen'

• UPDATE Persons SET LastName=Nilsen WHERE LastName=Hansen

• UPDATE Persons SET LastName=Nilsen WHERE LastName='Hansen'

12. What is the function that combines two strings and returns the combined string?

Answers:

• COMBINE()

• CONCATENATE()

• CONCAT()

• JOIN()

• GROUP()

13. What data is this statement trying to query from the Customers Table?  SELECT * FROM Customers WHERE City LIKE '[!bsp]%'

Answers:

• Customers in cities NOT starting with "b" or "s" or "p."

• Customers in cities containing any combination of the letters "b" and "s" and "p."

• Customers in cities starting with "bsp."

• Customers in cities starting with "b" or "s" or "p."

• Customers in cities ending with "b" or "s" or "p."

14. Choose correct clause: SELECT CountryCode, COUNT(*) FROM City GROUP BY CountryCode _____ COUNT(*) > 20;

Answers:

• SELECT

• HAVING

• ORDER BY

• LIMIT

• WHERE

15. Which of these is NOT a valid data type for a character string?

Answers:

• NVARCHAR

• CHAR

• TEXTCHAR

• VARCHAR

• NCHAR

16. A trigger is a database object that is attached to a table.  It is most similar to what other database process?

Answers:

• stored procedure

• cursor

• result set

• view

17. What is an alternate way of writing the following statement:   WHERE "column_name" IN ('value1')

Answers:

• WHERE "column_name" > 'value1'

• WHERE "column_name" = 'value1'

• WHERE "column_name" CONTAINS 'value1'

• WHERE "column_name" < 'value1'

• WHERE "column_name" INCLUDES 'value1'

18. Which statement removes all rows from the "orders" table without removing the table structure?

Answers:

• DROP TABLE orders

• SANITIZE orders

• TRUNCATE orders

• REMOVE ROWS FROM orders

19. Which of the following DROP statements is incorrect?

Answers:

• DROP TABLE

• DROP DATABASE

• DROP INDEX

• DROP ROW

20. This example illustrates use of the FULL JOIN action.  Which clauses must fill the three blanks for the query to be valid?  _______ e1."Event_Name", v2."Venue" FROM "events" e1  _______ "venues" v2 ON (e1."VenueNo" = v2."VenueNo") _______ e1."Event_Name" ASC, v2."Venue" ASC

Answers:

• SELECT, OUTER JOIN, GROUP BY

• WHERE, FULL OUTER JOIN, HAVING

• SELECT, FULL OUTER JOIN, ORDER BY

• GROUP BY, FULL OUTER JOIN, ORDER BY

• HAVING, WHERE, ORDER BY

21. What KEYWORD is used to filter groups?

Answers:

• MINIMIZE

• FILTER

• SORT

• HAVING

• GROUPS

22. Which does not describe a database element?

Answers:

• index

• table schema

• stored procedure

• tuple

• organic list

23. How do you select a column named "FirstName" from a table named "Persons"?

Answers:

• SELECT * FROM Persons where FirstName = Persons;

• SELECT * FROM Persons where Persons = FirstName;

• SELECT FirstName FROM Persons;

• SELECT First_Name FROM Persons;

24. SELECT * FROM tablea, tableb  WHERE tablea.DepartmentID = tableb.DepartmentID;  Which of these keywords will have the same effect as the above query?

Answers:

• Left Outer Join

• Full Outer Join

• Inner Join

• Right Outer Join

• Cross Join

25. Indexes can be created on existing tables so that information can be retrieved more quickly.  Specifically, what are indexes created on?

Answers:

• duplicate values

• null values

• columns

• rows

26. Which of the following names is NOT a SQL based RDBMS?

Answers:

• SQL Server

• MySQL

• SQLite

• Oracle

• MongoDB

27. What is the operator for nonequality?

Answers:

• less than greater than (<>)

• equal equal (==)

• greater than less than (><)

• equal exclamation (=!)

28. What character is used to connect a table name with a column name to create a fully qualified column name?

Answers:

• dot (.)

• dash (-)

• underscore (_)

• plus (+)

29. Which keyword is used more than once in a SQL statement that contains a subquery?

Answers:

• ORDER BY

• DISTINCT

• SELECT

• GROUP BY

30. What is the correct syntax to concatenate the contents of one column (col1) to the contents of another column (col2) in a query?

Answers:

• concat(col1, col2)

• concatenate(col1, col2)

• join(col1, col2)

• col1 + col2

• sql_concat(col1, col2)

31. Which of the following is NOT true about a primary key constraints?

Answers:

• A primary key column cannot contain NULL values.

• The value of a primary key constraint uniquely identifies each record in a table.

• Primary keys must contain unique values.

• For every primary key there must be a foreign key.

32. Which will select the `name` of  'John' from the 'Person' table where `num_friends` is greater than 1?

Answers:

• SELECT * FROM Person WHERE num_friends MORE THAN 1 AND name = 'John'

• SELECT name FROM Person WHERE num_friends > 1 AND name = 'John'

• SELECT CONCAT(firstname, lastname) FROM Person WHERE num_friends > 1 AND name = "John"

• SELECT "John" as 'name' FROM `Person` WHERE `num_friends` > 1

33. The HAVING clause can be used for what purpose?

Answers:

• To be used for filtering based on the outcome of non-aggregate functions.

• To be used for filtering based on the outcome of aggregate functions.

• To verify that at database connection is available.

• To validate a constraint.

34. Where is the GROUP BY clause placed in the sequence of statements?

Answers:

• before ORDER BY

• before SELECT

• before WHERE

• before FROM

35. What keyword is used to check for a range of values?

Answers:

• BETWEEN

• RANGE

• CONTAINS

• WITHIN`

36. What happens if you omit the WHERE clause in a SQL DELETE query?

Answers:

• An error message will appear.

• All tables will be deleted.

• The entire database will be deleted.

• All records will be deleted.

37. An asterisk after SELECT can be used to return all ________ of  a table.

Answers:

• null values

• columns

• primary keys

• row IDs

• foreign keys

38. The HAVING clause is used in conjunction with (and immediately after) what other clause?

Answers:

• WHERE

• FROM

• SELECT

• GROUP BY

39. How many primary keys can a table have?

Answers:

• one

• no limit

• between one and five

• at least one, but not more than two

• tables cannot have primary keys

40. The DDL term "DROP" does what?

Answers:

• Modifies the structure of an existing object in various ways.

• Deletes all data from a table in a very fast way, deleting the data inside the table and not the table itself.

• Moves data from one table down to the next.

• Eliminates errors from the current table.

• Deletes a database, table, index or column.

41. What keyword is used to create a table alias?

Answers:

• NEW_TABLE

• NICKNAME

• AS

• ALIAS

42. In SQL what is the meaning of NULL?

Answers:

• no value

• Empty string

• 0

43. What clause is used to sort data and group it?

Answers:

• GROUP

• SORT BY

• GROUP BY

• SORT

44. Which SQL function or feature returns a single value, calculated from values in a column?

Answers:

• bundle feature

• aggregate function

• collapse query

• consolidation function

45. If tableA is CROSS JOINED to tableB, tableA has 10 rows and tableB has 5 rows, what is the greatest possible size of the result set?

Answers:

• 20

• 50

• 25

• 15

• 5

46. Which of the following are type(s) of DML Triggers?

Answers:

• Instead of Trigger: Instead of Triggers are fired in place of the triggering action such as an insert, update, or delete.

• After Trigger: After triggers execute following the triggering action, such as an insert, update, or delete.

• All of these

47. What is the name for a query embedded inside another query?

Answers:

• subquery

• embedded query

• cartesian join

• inner join

48. What syntax would you use to write a query to select all teams that won either 2, 4, 6 or 8 games?

Answers:

• SELECT team_name FROM teams WHERE team_won MAP (2, 4, 6, 8)

• SELECT team_name FROM teams WHERE team_won LIKE (2, 4, 6, 8)

• SELECT team_name FROM teams WHERE team_won IN (2, 4, 6, 8)

• SELECT team_name FROM teams WHERE team_won ON (2, 4, 6, 8)

49. Which of the following is NOT a language element of SQL?

Answers:

• Data mining

• Expression

• Clause

• Query

• Statement

50. What keyword is used with aggregate functions to include only unique values in the calculation?

Answers:

• UNIQUE

• DISTINCT

• NO_DUPLICATES

• SINGLE

51. What is one of the purposes of normalization?

Answers:

• Add primary keys

• Eliminate redundancy

• Join tables

• Eliminate rows

• Fix tables

52. What term is used to describe the "layout" of a database or the blueprint that outlines the way data is organized into tables?

Answers:

• query

• schema

• program

• view

53. Which of the following is the correct syntax to update a table?

Answers:

• UPDATE "table name" AND SET "column name" = <value> WHERE <constraint>;

• UPDATE "table name" SET "column name" = <value> WHERE <constraint>;

• UPDATE "table name" WHERE <constraint> SET "column name" = <value>;

• SET "column name" = <value> WHERE <constraint> UPDATE "table name";

54. What is the term for a column (or set of columns) whose values uniquely identify every row in a table?

Answers:

• unique identifier

• foreign key

• primary key

• secondary key

55. What is the difference between DROP and DELETE.

Answers:

• DELETE removes an entire table and DROP removes all the rows in the table.

• Both delete a specified row in a table.

• DELETE removes a row in the table and DROP removes the entire table.

• Both delete an entire table.

56. A primary key made up of more than one column is referred to as what kind of key?

Answers:

• artificial key

• dynamic key

• composite key

• monk key

• spare key

57. What function calculates a column's average value?

Answers:

• AVERAGE()

• MEAN()

• MEDIAN()

• AVG()

58. What does RDBMS mean?

Answers:

• Relational Database Manager System

• Ratio Database Management System

• Relational Database Management System

• Rational Database Manager System

• Rational Database Management System

59. What keyword is used in conjunction with the WHERE clause when creating a subquery?

Answers:

• IN

• EMBED

• SUB

• QUERY

60. What is the name of a mechanism used to associate tables within a SELECT statement?

Answers:

• association

• join

• connection

• link

61. What function is used to remove padded spaces?

Answers:

• TRIM()

• RPAD()

• LPAD()

• PAD()

62. When accessing data from a table which keyword is used immediately before the table name?  (Example: SELECT column_name _______ table_name;)

Answers:

• JOIN

• INSERT

• WHERE

• FROM

• INSIDE

63. Which keyword is used to sort retrieved data in reverse order?

Answers:

• UPSIDEDOWN

• BACKWARDS

• DESC

• REVERSE

64. Which aggregate function returns the total of the values in a column?

Answers:

• SUM()

• ALL()

• ADD()

• TOTAL()

65. The FROM keyword is used to identify which piece of information?

Answers:

• column name

• database name

• row name

• table name

66. True or false  The ORDER BY keyword is used to sort the result-set by one or more columns.

Answers:

• False

• True

67. What is one objective of database normalization?

Answers:

• defining indexes

• using multiple tables

• using norm-based ASCII

• reducing redundancy

68. Which of the following is NOT a valid aggregate function?

Answers:

• Sum()

• Max()

• Min()

• Avg()

• Round()

69. Which keyword is used to assign an alias?

Answers:

• RENAME

• ASSIGN

• ALIAS

• AS

70. What is another name for a table row?

Answers:

• record

• view

• query

• data

71. Which keyword is used to retrieve only certain rows of data?

Answers:

• RECORD

• WHERE

• ROWS

• FILTER

72. Which of the following statements can be used to undo a transaction?

Answers:

• RESET

• ROLLBACK

• UNDO

• REDO

73. What is the definition of a foreign key?

Answers:

• A primary key in a relational table that has a non-numeric value.

• A field in a relational table that matches the primary key column of another table.

• A primary key with a null value.

• The secondary primary key in a table.

74. What does the acronym SQL stand for?

Answers:

• Standard Query Language

• Simple Query Language

• Specified Query Language

• Structured Query Language

• Segmented Query Language

75. What function returns the lowest value in a column?

Answers:

• MIN()

• SMALLEST()

• LOWEST()

• LOW()

76. What statement must be placed in the blank space at the beginning of this query in order for it to be valid?  ______ Movie.title,        COUNT(*) AS Directors     FROM  Movie JOIN Movie_director        ON Movie.isbn = Movie_director.isbn     GROUP BY Movie.title

Answers:

• ORDER BY

• WHERE

• FROM

• ON

• SELECT

77. Which command is used to sort retrieved data?

Answers:

• NUMERIC

• ALPHA

• ORDER BY

• SORT

78. The 'JOIN' keyword is used to:

Answers:

• Join two tables end-to-end permanently.

• Join two databases together permanently.

• Join two tables in a query operation.

• Join two databases in a query operation.

79. What is a primary key?

Answers:

• The index that is accessed most often

• A table

• The first attribute of a table.

• A reference to a row in another table

• A unique identifier within all record sets.

80. Which of the following is NOT a basic SQL statement?

Answers:

• SELECT

• UPDATE

• INSERT

• QUERY

• DELETE

81. What keyword is used to check for no value?

Answers:

• VOID

• NULL

• NONE

• EMPTY

82. What keyword is used to retrieve table data?

Answers:

• SELECT

• RETRIEVE

• FETCH

• GET

83. What is DDL Stand for?

Answers:

• Data Distribution Layout

• Data Deprecation Logic

• Data Definition Language

• Data Determined Login

84. Which of the following is NOT included as a field in the timestamp data type?

Answers:

• Year

• Month

• Hour

• Day

• Century

85. Which character is used to retrieve all columns of data?

Answers:

• exclamation (!)

• dollar sign ($)

• pound sign (#)

• asterisk (*)

86. When sorting by multiple columns, which character is used to separate column names?

Answers:

• coma (,)

• semicolon (;)

• dash (-)

• backslash (\)

87. Of the following sequences which one is in the correct order?

Answers:

• SELECT | FROM | GROUP BY | HAVING

• FROM | GROUP BY | HAVING | SELECT

• GROUP BY | FROM | SELECT | HAVING

• HAVING | FROM | SELECT | GROUP BY

88. Which SQL statement is used to update data in a database?

Answers:

• UPDATE ROW

• RENAME

• UPDATE

• UPDATE DATA

• CHANGE

89. Which character is used to end a SQL statement?

Answers:

• colon (:)

• semicolon (;)

• exclamation (!)

• period (.)

90. What function counts the number of rows in a column?

Answers:

• COUNT()

• ADD()

• NUMBER()

• TOTAL()

91. What function returns the highest value in a column?

Answers:

• HIGHEST()

• HIGH()

• BIGGEST()

• MAX()

92. What does SQL stand for?

Answers:

• Structured Query Language

• Static Question Logic

• Simultaneous Quiz Language

• Sequential Quest for Learning

93. What visual technique is commonly used to format subqueries?

Answers:

• indenting

• bolding

• color coding

• numbering

94. If a foreign key constraint is violated, the default action taken by the DBMS is what?

Answers:

• The DBMS throw an error but implements the violated changes

• The value is cascaded

• The value is set to NULL

• It is not possible to violate a foreign key constraint. The modification is rejected

95. What keyword is used with aggregate functions to include every value in the calculation?

Answers:

• TOTAL

• DUPLICATES_ALLOWED

• ALL

• EVERY

96. Which wildcard character means "match any number of occurrences of any character"?

Answers:

• ampersand (&)

• asterisk (*)

• percent (%)

• at (@)

97. What is the result of "select * from table where 1"

Answers:

• Return the first row from table

• Return all the rows from table

98. UNION ALL is different from a UNION command in that...

Answers:

• UNION ALL will not eliminate duplicate rows

• UNION ALL is an invalid command

• UNION ALL will include null values

• UNION ALL will only select distinct values

99. A Cross Join is equivalent to:

Answers:

• A Cartesian Product

• Left Outer Join

• Full Join

• Right Outer Join

• Natural Join

100. What is the name of a result that returns all the rows in all the tables listed in the query?

Answers:

• null value

• mega join

• table constraint

• primary key

• Cartesian product

101. What is the first query to run in a statement that contains subqueries?

Answers:

• innermost

• first

• last

• outermost

102. What records would the result set of this query include? SELECT * FROM tableA LEFT OUTER JOIN tableB ON tableA.key = tableB.key

Answers:

• All records from tableA; all records from tableB

• 0 or more records from tableA; all records from tableB

• All records from tableA; 0 or more records from tableB

• Only records where key is in both tableA and tableB

103. What is the proper syntax of the keyword LIMIT to display 5 results after starting at record 4?

Answers:

• LIMIT 4, 5

• LIMIT 0, 4

• LIMIT 0, 5

• LIMIT 5, 4

104. Which is the correct order for a proper SQL query?

Answers:

• SELECT, FROM, WHERE, GROUP BY, HAVING, ORDER BY

• SELECT, FROM, WHERE, GROUP BY, ORDER BY, HAVING

• SELECT, FROM, WHERE, HAVING, ORDER BY, GROUP BY

• SELECT, FROM, WHERE, HAVING, GROUP BY, ORDER BY

• SELECT, FROM, GROUP BY, HAVING, ORDER BY, WHERE

105. What is the name of the category of functions used to summarize data?

Answers:

• primary

• grouping

• summary

• aggregate

106. What is the correct procedure to create and use a cursor?

Answers:

• Declare cursor > Open cursor > Fetch row from the cursor > Process fetched row > Close cursor > Deallocate cursor

• Open cursor > Fetch row from the cursor > Process fetched row > Deallocate cursor > Close cursor

• Declare cursor > Open cursor > Fetch row from the cursor > Process fetched row > Deallocate cursor > Close cursor

• Open cursor > Fetch row from the cursor > Process fetched row > Close cursor > Deallocate cursor

107. The UNION ALL operator performs which of the following actions?

Answers:

• Returns the output from the query before and the query after the operator excluding duplicates.

• Returns the output from the query before and the query after the operator including duplicates.

• Joins all of the tables that have a primary or foreign key relationship to the specified table.

• Concatenates all of the columns in the table specified with an optional user defined delimiter between.

108. What is the correct syntax for using a CASE statement?

Answers:

• CASE {value/column} WHEN {Boolean Condition} THEN {Value} ELSE {Value} END

• CASE WHEN {Boolean Condition} END

• None of these

• CASE {value/column} WHEN {Boolean Condition} THEN {Value} ELSE {Value} END CASE

• CASE {value/column} WHEN {Boolean Condition} THEN {Value} ELSE CREATE PROCEDURE

109. Where can we find subquery within another statement?

Answers:

• In the SELECT clause.

• In the JOIN clause.

• In the FROM clause.

• In the HAVING clause.

• In all these clauses.

110. If you INNER JOIN tableA (which has 10 rows) with tableB (which has 5 rows), what is the smallest possible amount of rows that can be returned?

Answers:

• 15

• 5

• 50

• 0

• 20

111. Which of these is not a valid constraint?

Answers:

• EXISTS

• PRIMARY KEY

• UNIQUE

• NOT NULL

• CHECK

112. Which of the following is NOT a property of a relational table?

Answers:

• Column values are of the same kind.

• Every table must include a foreign key.

• Each column must have a unique name.

• The sequence of columns is insignificant.

113. Which of the following statements about indexes is NOT correct?

Answers:

• Adding additional indexes can greatly improve performance in an OLAP environment.

• Adding additional indexes increases the storage space required for your database.

• Adding additional indexes can result in reduced write speeds.

• Adding additional indexes cannot decrease the performance of your database.

114. What is the difference between a unique key and primary key?

Answers:

• A unique key will allow NULL values

• A primary key by default has an index, a unique key does not

• They are the same

• A unique key can be used as part of a foreign key relationship but a primary key cannot

• A primary key can be used as part of a foreign key relationship but a unique key cannot

115. How can you insert several records in TABLE1 that already exist in TABLE2?

Answers:

• insert into TABLE1 (FIELD1) select FIELD2 from TABLE2

• insert into TABLE1 (FIELD1) values (TABLE2.FIELD2)

• insert into TABLE1 (FIELD1) values (select FIELD2 from TABLE2)

• insert into TABLE1 (FIELD1) select FIELD2 , FIELD3, FIELD4 from TABLE2

116. What is a collation?

Answers:

• An alphabet for a character data type.

• A set of rules that sort and compare characters.

• A character encoding for a character data type.

• A concatenation of two columns containing characters.

117. How many clustered indexes can a table have?

Answers:

• 0

• 1

• 128

• 2

• no limit

118. Which of the following types of triggers can be used with a view?

Answers:

• After Update

• Instead of Update

• After Delete

• Before Update

• Before Insert

119. Which of the following is a valid isolation level?

Answers:

• Read Commited

• Concurrent

• Write Committed

• Repeatable Write

• Serial

120. What code would find the position of the character 'D' in the string 'ABCDE' - starting at position 1?

Answers:

• VARCHAR('ABCDE','D',1)

• CHARINDEX('ABCDE','D',1)

• CHARINDEX('D','ABCDE',1)

• VARCHAR(1,'D','ABCDE')

• PATINDEX('D','ABCDE',1)

121. Which of the following KEYWORDS will return the first NON-NULL value from a list of columns?

Answers:

• COALESCE

• ISNULL

• GATHER

• NOTNULL

• PARSENULL

122. If tableA is LEFT JOINED to tableB, tableA has 10 rows and tableB has 5 rows, what is the greatest possible size of the result set?

Answers:

• 15

• 5

• 50

• 20

• 10

123. A recursive CTE would contain which of the following?

Answers:

• Except

• Union

• Intersect

• Union All

124. What is the equivalent sql statement of following statement? Select sum(column1) a, count(column2) b from TableA where 1=2

Answers:

• Select 0 a, 0 b from TableA

• Select sum(column1) a, count(*) b from TableA

• Select sum(*) a, count(*) b from TableA where 1=2

• Select sum(1) a, count(2) b from TableA where column1=column2

• Select sum(column1) a, count(column2) b from TableA where column1=column2

125. A function differs from a procedure in all the following ways EXCEPT...

Answers:

• A function must return a value or table.

• Only a function can accept parameters.

• A function cannot utilize error handling (TRY...CATCH).

• A function cannot perform permanent environmental changes to a server.

• Only a function can be called in a SELECT clause.

126. Which SQL statement will return an error?

Answers:

• USE PEOPLE; UPDATE people SET name = 'john' WHERE name != 'john'

• None of these statements will return an error

• SELECT ALL FROM people WHEN date > '2011-01-01'

• SELECT ALL FROM table WHERE state IS Alabama

127. Other things being equal, which queries are the fastest?

Answers:

• Not relevant.

• Queries including correlated subqueries.

• Queries including uncorrelated subqueries.