ABS and MOD functions in SQL

Introduction

ABS and MOD help you work with numbers by finding the positive value and the remainder after division.

When you want to ignore negative signs and get only positive numbers.

When you need to find out what remains after dividing one number by another.

When calculating distances or differences where only positive values make sense.

When splitting items into groups and checking how many are left over.

When working with cycles or repeating patterns in numbers.

Syntax

SQL

ABS(number)
MOD(number, divisor)

ABS returns the positive value of the number, even if it was negative.

MOD returns the remainder after dividing number by divisor.

Examples

Returns 10 because ABS removes the negative sign.

SQL

SELECT ABS(-10);

Returns 1 because 10 divided by 3 leaves a remainder of 1.

SQL

SELECT MOD(10, 3);

Returns 5 because the number is already positive.

SQL

SELECT ABS(5);

Returns 4 because 14 divided by 5 leaves a remainder of 4.

SQL

SELECT MOD(14, 5);

Sample Program

This query shows the absolute value of -25 and the remainder when 25 is divided by 4.

SQL

SELECT ABS(-25) AS absolute_value, MOD(25, 4) AS remainder;

Important Notes

ABS always returns a non-negative number.

MOD result is always less than the divisor and has the same sign as the dividend in some SQL dialects.

If divisor is zero in MOD, it will cause an error.

Summary

ABS gives the positive version of any number.

MOD finds the leftover part after division.

Both are useful for handling numbers in everyday tasks.

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