WHERE Condition to Exclude Amounts with Decimals Ending with ‘0’s or ‘5’s

Introduction

As a technical blogger, I’ve encountered numerous SQL queries where excluding specific values is necessary. In this article, we’ll delve into the world of conditional statements in SQL and explore ways to exclude amounts that end with decimals ‘0’ or ‘5’.

Understanding the Problem

The problem at hand involves a decimal column ‘amount’ in a table. We want to exclude rows where the amount value ends with either ‘0’s or ‘5’s. This is a common requirement in data analysis and reporting, as it helps to identify invalid or incorrect values.

Casting and Modulus Operation

To tackle this problem, we’ll use a combination of casting and modulus operations. The idea is to multiply the decimal value by 100 (since there are two digits after the decimal point), convert it to an integer using casting, and then apply the modulus operation.

The modulus operator (%) returns the remainder when the dividend is divided by the divisor. In this case, we’re interested in values that don’t end with ‘0’s or ‘5’s. Let’s explore how this works:

# Casting and Modulus Operation

When you multiply a decimal value by 100, it shifts the decimal point two places to the right.
For example:
10.25 * 100 = 1025 (integer)
11.20 * 100 = 1120 (integer)

Now, let's apply the modulus operation:
1025 % 5 = 0 ( incorrect - we want to exclude this value)
1120 % 5 = 0 (incorrect - we want to exclude this value)

However, if we cast the original decimal value instead of its multiplied version:
(10.25 * 100) % 5 = (1025) % 5 = 0 (incorrect - we want to exclude this value)
((10.25) % 100) % 5 = 25 % 5 = 0 (correct!)

Similarly, for the second example:

(11.20 * 100) % 5 = (1120) % 5 = 0 (incorrect - we want to exclude this value)
((11.20) % 100) % 5 = 120 % 5 = 0 (incorrect - we want to exclude this value)
((11.2) % 100) % 5 = 12 % 5 = 2

By casting the original decimal value instead of its multiplied version, we can accurately identify values that end with '0's or '5's.

SQL Query Using Modulus Operation

Now that we’ve explored the concept behind the modulus operation, let’s create a SQL query to exclude amounts ending with ‘0’s or ‘5’s:

# SQL Query Using Modulus Operation

SELECT *
FROM your_table
WHERE (CAST(your_field * 100 AS INTEGER) % 10) != 0;

In this query:

We cast the your_field value multiplied by 100 to an integer using the CAST() function.
We apply the modulus operation (%) with a divisor of 10, which effectively checks for values ending with ‘0’s or ‘5’s (00 and 05, respectively).
We exclude rows where the result is equal to 0, indicating that the original value ended with ‘0’ or ‘5’.

Alternative Solutions

While the approach above works well, there are alternative solutions worth exploring:

Using a Regular Expression

Regular expressions can be used to match patterns in string values. In this case, we can use a regular expression to exclude amounts ending with ‘0’s or ‘5’s:

# SQL Query Using Regular Expression

SELECT *
FROM your_table
WHERE your_field NOT LIKE '%[05][0-9]$';

In this query:

We use the NOT LIKE operator to exclude rows where the value matches a specific pattern.
The pattern '[05][0-9]$' matches any string that ends with either ‘0’ or ‘5’, followed by one or more digits (0-9).

Using a Custom Function

Another approach is to create a custom function that checks for decimal values ending with ‘0’s or ‘5’s. Here’s an example:

# SQL Query Using Custom Function

CREATE FUNCTION ends_with_zero_or_five(
    @value DECIMAL(10, 2)
) RETURNS BIT AS BEGIN
    DECLARE @multiplied_value INT = (@value * 100)
    RETURN (ABS(@multiplied_value % 10)) = 5 OR ABS(@multiplied_value % 10) = 0;
END;

SELECT *
FROM your_table
WHERE NOT EXISTS (
    SELECT 1 FROM ends_with_zero_or_five(your_field)
);

In this query:

We create a custom function ends_with_zero_or_five() that takes a decimal value as input.
The function multiplies the input value by 100, then applies the modulus operation to check for values ending with ‘0’s or ‘5’s.
We exclude rows where the result is equal to 0 or 5 using the NOT EXISTS operator.

Conclusion

In this article, we’ve explored ways to exclude amounts that end with decimals ‘0’ or ‘5’. By casting and applying the modulus operation, we can accurately identify these values in SQL queries. We’ve also discussed alternative solutions using regular expressions and custom functions, which can be useful depending on the specific requirements of your project.

When working with decimal columns, it’s essential to consider the nuances of floating-point arithmetic and rounding issues. By understanding the underlying concepts and techniques, you’ll be better equipped to tackle complex data analysis tasks and create efficient SQL queries that meet your needs.

Last modified on 2023-11-09