Resolving the Conversion failed when converting date and/or time from character string Error in SQL

Learn how to troubleshoot and fix common SQL errors related to date conversions, ensuring smooth data handling in your SQL queries.
---

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Conversion failed when converting date and/or time from character string. SQL query

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Understanding and Fixing the Date Conversion Error in SQL

When working with SQL queries, developers can sometimes encounter perplexing error messages. One such common issue is the error: "Conversion failed when converting date and/or time from character string." This error typically arises when there's an issue with converting a character string to a date type in SQL Server. In this guide, we will explore the causes of this error and the steps you can take to fix it. Let’s dive in!

The Problem: What Causes the Conversion Error?

Imagine you have a SQL query that retrieves data from multiple tables, and your goal is to convert string representations of dates into date format. However, if even one of those strings cannot be accurately converted into a date, SQL Server will throw an error. This situation can occur for several reasons, including:

Invalid Date Formats: The string may not match the expected date format.

Null or Blank Strings: Attempting to convert a NULL or empty string can lead to errors.

In this specific case, the original SQL query was designed to select data from various tables and calculate the difference in days between the converted date values and the current date. However, when adding an INTO statement to create a new table with this data, SQL Server raises the error message.

The Solution: Steps to Resolve the Error

Step 1: Modify the Date Conversion Logic

To prevent the error from occurring, you can use the TRY_CONVERT function. This function attempts to convert a value to the specified data type and returns NULL when the conversion fails, rather than generating an error. Here’s how to implement this change:

Original line of date calculation:

[[See Video to Reveal this Text or Code Snippet]]

Revised query using TRY_CONVERT:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Simplifying the Query

Depending on your needs, you may not even need the CASE statement. If you simply want to avoid errors and let problematic rows result in NULL, your query can be simplified as follows:

[[See Video to Reveal this Text or Code Snippet]]

Step 3: Test Each Component

It’s important to ensure that each part of your query works as expected:

Test the Adjusted Query: Run the revised SQL query to verify that it completes without errors and returns the desired results.

Conclusion

Encountering the "Conversion failed when converting date and/or time from character string" error can be frustrating, but understanding its causes and knowing how to implement solutions can make a significant difference in your SQL programming experience. By using TRY_CONVERT and simplifying your queries, you can avoid these pitfalls, ensuring successful data handling within your SQL Server environment.

Feel free to share your thoughts or further questions regarding SQL errors and solutions in the comments below!