ABS and MOD functions in SQL - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the ABS function do in SQL?

The ABS function returns the absolute value of a number, which means it removes any negative sign and gives the positive value.

beginner

What is the result of MOD(10, 3) in SQL?

MOD(10, 3) returns 1 because 10 divided by 3 leaves a remainder of 1.

beginner

How can ABS and MOD functions be useful in real life?

ABS helps when you only want the size of a number, ignoring if it is negative, like distance. MOD helps find remainders, useful for things like checking if a number is even or odd.

beginner

Write a SQL query to find the absolute value of -15.

SELECT ABS(-15) AS absolute_value;

beginner

Write a SQL query to find the remainder when 29 is divided by 5.

SELECT MOD(29, 5) AS remainder;

What does the ABS function return for ABS(-7)?

A -7

B NULL

C 0

D 7

ABS returns the positive value, so ABS(-7) is 7.

What is the result of MOD(14, 4)?

A 4

B 0

C 2

D 3

14 divided by 4 leaves a remainder of 2, so MOD(14, 4) is 2.

Which SQL function would you use to get the remainder of a division?

A ABS

B MOD

C SUM

D AVG

MOD returns the remainder after division.

What does ABS(0) return?

A 0

B -0

C NULL

D 1

The absolute value of 0 is 0.

If MOD(25, 5) is calculated, what is the result?

A 0

B 5

C 1

D 25

25 divided by 5 has no remainder, so MOD(25, 5) is 0.

Explain what the ABS function does and give an example of when you might use it.

Think about how negative numbers can be turned positive.

Describe the MOD function and how it can help determine if a number is even or odd.

Consider dividing by 2 to check even or odd.

Practice

1. What does the SQL function ABS(-15) return?

easy

A. 15

B. -15

C. 0

D. Error

Solution

1. Step 1: Understand the ABS function

   The ABS function returns the absolute value, which means it removes any negative sign from a number.

2. Step 2: Apply ABS to -15

   Applying ABS to -15 gives 15 because it converts the negative number to positive.

3. Final Answer:

   15 -> Option A

4. Quick Check:

   ABS(-15) = 15 [OK]

Hint: ABS always returns a positive number or zero [OK]

Common Mistakes:

• Thinking ABS changes positive numbers
• Confusing ABS with MOD
• Expecting ABS to return negative values

2. Which of the following is the correct syntax to get the remainder of 17 divided by 5 using SQL?

easy

A. SELECT MOD(17, 5);

B. SELECT REMAINDER(17, 5);

C. SELECT 17 % 5;

D. SELECT ABS(17, 5);

Solution

1. Step 1: Identify the correct function for remainder

   In standard SQL, the MOD function returns the remainder after division.

2. Step 2: Check syntax correctness

   MOD takes two arguments: dividend and divisor, so MOD(17, 5) is correct syntax.

3. Final Answer:

   SELECT MOD(17, 5); -> Option A

4. Quick Check:

   MOD syntax = MOD(dividend, divisor) [OK]

Hint: Use MOD(a, b) to get remainder in SQL [OK]

Common Mistakes:

• Using ABS instead of MOD
• Using % which is not standard SQL
• Using REMAINDER which is not standard SQL

3. What is the result of this SQL query?

SELECT ABS(-7) + MOD(20, 6) AS result;

medium

A. 2

B. 8

C. 14

D. 9

Solution

1. Step 1: Calculate ABS(-7)

   ABS(-7) returns 7 because it converts negative to positive.

2. Step 2: Calculate MOD(20, 6)

   20 divided by 6 is 3 with remainder 2, so MOD(20, 6) = 2.

3. Step 3: Add the two results

   7 + 2 = 9.

4. Final Answer:

   9 -> Option D

5. Quick Check:

   ABS(-7) + MOD(20, 6) = 9 [OK]

Hint: Calculate ABS and MOD separately, then add [OK]

Common Mistakes:

• Adding MOD result incorrectly
• Confusing ABS with MOD
• Ignoring negative sign in ABS

4. Identify the error in this SQL query:

SELECT ABS(10, -5) FROM dual;

medium

A. MOD function should be used instead

B. ABS function takes only one argument

C. Missing FROM clause

D. ABS cannot be used with negative numbers

Solution

1. Step 1: Check ABS function argument count

   ABS accepts only one argument, but here it has two (10, -5), which is invalid.

2. Step 2: Understand correct usage

   To get remainder, MOD should be used, but the question asks about error in ABS usage.

3. Final Answer:

   ABS function takes only one argument -> Option B

4. Quick Check:

   ABS single argument only [OK]

Hint: ABS needs exactly one number inside parentheses [OK]

Common Mistakes:

• Using multiple arguments in ABS
• Confusing ABS with MOD
• Ignoring function argument rules

5. You want to find all rows in a table numbers where the absolute value of value is less than 10 and the remainder when value is divided by 3 is 1. Which SQL WHERE clause is correct?

hard

A. WHERE MOD(ABS(value), 3) = 1 AND value < 10

B. WHERE ABS(value) > 10 OR MOD(value, 3) = 1

C. WHERE ABS(value) < 10 AND MOD(value, 3) = 1

D. WHERE ABS(value) < 10 AND MOD(value, 3) = 0

Solution

1. Step 1: Understand the conditions

   We want rows where absolute value of 'value' is less than 10 and remainder of 'value' divided by 3 equals 1.

2. Step 2: Translate conditions into SQL

   ABS(value) < 10 ensures absolute value less than 10; MOD(value, 3) = 1 ensures remainder 1.

3. Step 3: Check options

   WHERE ABS(value) < 10 AND MOD(value, 3) = 1 matches both conditions exactly with AND.

4. Final Answer:

   WHERE ABS(value) < 10 AND MOD(value, 3) = 1 -> Option C

5. Quick Check:

   Use AND to combine ABS and MOD conditions [OK]

Hint: Combine ABS and MOD with AND for multiple conditions [OK]

Common Mistakes:

• Using OR instead of AND
• Mixing up MOD values
• Applying MOD to ABS result incorrectly