10 Simple Ways To Convert Double To Int In Trino

Converting data types is a crucial task in any data processing environment, and when working with Trino (formerly known as Presto), converting a DOUBLE to an INT can be particularly important for performance optimization and meeting schema requirements. This blog post will explore 10 simple ways to convert DOUBLE to INT in Trino. Whether you're a beginner or a seasoned data engineer, these tips will help you navigate this process effectively. Let's get started! 💻

Understanding Double and Int Data Types in Trino

Before diving into the conversion methods, it's important to understand the data types you'll be working with:

• DOUBLE: This is a floating-point number representation, which can store decimal values and is typically used for numerical computations requiring a high degree of precision.
• INT: This is an integer representation, which only stores whole numbers without any decimal component.

In many cases, converting a DOUBLE to an INT may be necessary when you want to discard the decimal portion, aggregate data, or improve performance.

1. Using the CAST Function

The most straightforward way to convert a DOUBLE to an INT in Trino is by using the CAST function.

SELECT CAST(double_column AS INT) FROM your_table;

2. Using the TRUNC Function

If you want to convert a DOUBLE to an INT without rounding, TRUNC can be a great option.

SELECT TRUNC(double_column) FROM your_table;

3. Rounding with ROUND Function

If you prefer rounding the DOUBLE before converting to INT, use the ROUND function:

SELECT CAST(ROUND(double_column) AS INT) FROM your_table;

4. Using FLOOR Function

The FLOOR function will always round down to the nearest whole number. It’s useful if you want to ensure that you never exceed the original number.

SELECT CAST(FLOOR(double_column) AS INT) FROM your_table;

5. Using CEIL Function

In contrast to FLOOR, the CEIL function rounds up to the nearest whole number.

SELECT CAST(CEIL(double_column) AS INT) FROM your_table;

6. Conditional Conversion with CASE Statement

Sometimes you might want to apply different logic based on certain conditions. Here’s how to do it with a CASE statement:

SELECT CASE
           WHEN double_column < 0 THEN 0
           ELSE CAST(double_column AS INT)
       END AS converted_value
FROM your_table;

7. Using Integer Division

Trino allows you to perform integer division that can effectively convert a DOUBLE to an INT.

SELECT double_column / 1 AS integer_value FROM your_table;

8. Direct Conversion by Multiplying and Casting

If you have a specific scenario in which you want to convert using multiplication, you can do so as follows:

SELECT CAST(double_column * 1 AS INT) FROM your_table;

9. Aggregating and Converting

If you're aggregating data, you can combine aggregation functions with type conversion:

SELECT CAST(SUM(double_column) AS INT) FROM your_table;

10. Using Subquery for More Complex Scenarios

Sometimes, you may need to do more complex manipulations. In such cases, utilizing a subquery for better control is helpful.

SELECT CAST(inner_table.avg_value AS INT)
FROM (SELECT AVG(double_column) AS avg_value FROM your_table) AS inner_table;

Common Mistakes to Avoid

• Precision Loss: Be aware that converting from DOUBLE to INT can result in precision loss. Double-check your requirements!
• Null Values: Make sure to handle any null values in your columns to avoid unexpected results. Using COALESCE is a great way to ensure you’re not working with nulls.

Troubleshooting Issues

If you encounter any issues when performing these conversions:

1. Check Data Types: Ensure the column type is indeed DOUBLE.
2. Handle NULL Values: If you get unexpected results, double-check how you are handling nulls.
3. Rounding Errors: Different functions will produce different rounding behaviors, so choose according to your needs.

<div class="faq-section"> <div class="faq-container"> <h2>Frequently Asked Questions</h2> <div class="faq-item"> <div class="faq-question"> <h3>What happens to the decimal part when converting a DOUBLE to INT?</h3> <span class="faq-toggle">+</span> </div> <div class="faq-answer"> <p>The decimal part is discarded unless you use rounding functions like ROUND, CEIL, or FLOOR.</p> </div> </div> <div class="faq-item"> <div class="faq-question"> <h3>Can I convert a negative DOUBLE to an INT?</h3> <span class="faq-toggle">+</span> </div> <div class="faq-answer"> <p>Yes, you can convert negative DOUBLE values to INT, but the result will also be negative.</p> </div> </div> <div class="faq-item"> <div class="faq-question"> <h3>How do I handle NULL values during conversion?</h3> <span class="faq-toggle">+</span> </div> <div class="faq-answer"> <p>You can use the COALESCE function to provide a default value for NULLs when converting.</p> </div> </div> </div> </div>

Recapping our exploration, converting a DOUBLE to an INT in Trino can be done using various functions like CAST, TRUNC, ROUND, and others. Each method serves a different purpose, depending on whether you want to discard decimals, round numbers, or apply custom logic through conditions. Make sure you also avoid common mistakes and troubleshoot issues effectively!

By familiarizing yourself with these techniques, you can enhance your data processing skills in Trino and manage your data conversions seamlessly. Keep practicing and exploring the Trino documentation for more insightful tutorials!

<p class="pro-note">💡Pro Tip: Experiment with different conversion methods to find the one that best suits your data processing needs!</p>