SQL - Functions

Question 1

Aggregate functions: What does AVG(column_name) do?

Answer 1

Returns the average value of a column.

Question 2

Aggregate functions: What does COUNT(column_name) do?

Answer 2

Returns the number of rows (without a NULL value) of a column.

Question 3

Aggregate functions: What does COUNT(*) do?

Answer 3

Returns the number of selected rows.

Question 4

Aggregate functions: What does FIRST(column_name) do?

Answer 4

Returns the value of the first record in a specified field.

Question 5

Aggregate functions: What does LAST(column_name) do?

Answer 5

Returns the value of the last record in a specified field.

Question 6

Aggregate functions: What does MAX(column_name) do?

Answer 6

Returns the highest value of a column.

Question 7

Aggregate functions: What does MIN(column_name) do?

Answer 7

Returns the lowest value of a column.

Question 8

Aggregate functions: What does SUM(column_name) do?

Answer 8

Returns the total sum of a column.

Question 9

Aggregate functions: What does FIRST(column_name) do?

not supported in SQLServer2K

Answer 9

Returns the value of the first record in a specified field.

Question 10

Aggregate functions: What does LAST(column_name) do?

not supported in SQLServer2K

Answer 10

Returns the value of the last record in a specified field.

Question 11

Scalar functions: What does UCASE(c) do?

Answer 11

Converts a field to upper case.

Question 12

Scalar functions: What does LCASE(c) do?

Answer 12

Converts a field to lower case.

Question 13

Scalar functions: What does MID(c,start[,end]) do?

Answer 13

Extract characters from a text field.

Question 14

Scalar functions: What does LEN(c) do?

Answer 14

Returns the length of a text field.

Question 15

Scalar functions: What does INSTR(c,char) do?

Answer 15

Returns the numeric position of a named character within a text field.

Question 16

Scalar functions: What does LEFT(c,number_of_char) do?

Answer 16

Return the left part of a text field requested.

Question 17

Scalar functions: What does RIGHT(c,number_of_char) do?

Answer 17

Return the right part of a text field requested.

Question 18

Scalar functions: What does ROUND(c,decimals) do?

Answer 18

Rounds a numeric field to the number of decimals specified.

Question 19

Scalar functions: What does MOD(x,y) do?

Answer 19

Returns the remainder of a division operation.

Question 20

Scalar functions: What does NOW() do?

Answer 20

Returns the current system date.

Question 21

Scalar functions: What does FORMAT(c,format) do?

Answer 21

Changes the way a field is displayed.

Question 22

Scalar functions: What does DATEDIFF(d,date1,date2) do?

Answer 22

Used to perform date calculations.