SQL Server gives you two functions for formatting values: FORMAT() and CONVERT(). They overlap enough that it’s not always obvious which one to reach for. This article skips the feature-by-feature breakdown and focuses on answering the question of which one you should use for a given scenario.
conversion functions
SQL Server CONVERT() Date Style Codes Explained (With Examples)
In SQL Server, dates are stored in one format but often need to be displayed in another. That’s where the CONVERT() function can help. It lets you take a date value and turn it into a string in whatever format you need, whether that’s MM/DD/YYYY for an American audience or DD-MM-YYYY for a universally recognized date format.
The tricky part when using this function is the style code. This a number you pass into CONVERT() that tells it which format to use. There are dozens of style codes, and they’re not exactly intuitive to memorise. This article breaks down the most useful ones with real examples so you can find what you need and move on.
How to Format Dates in SQL Server (A Beginner’s Guide)
Dates in SQL Server can be surprisingly tricky if you’re new to the game. The way dates are stored is not always the way you want them displayed, and figuring out how to convert one to the other is one of those things every beginner eventually Googles. So let’s walk through it clearly.
When to Use TRY_CONVERT() vs CONVERT() in SQL Server
Both CONVERT() and TRY_CONVERT() in SQL Server are used to convert data types, but they behave quite differently when something goes wrong. Understanding that difference can save you a lot of debugging time, especially when dealing with messy or unpredictable data.
Let’s look at when you should use each, and walk through an example that you can run yourself.
Fixing Invalid Date Conversions in SQL Server
When you work with dates in SQL Server, you’ll often run into situations where a value can’t be converted directly to a datetime or date. This usually happens because the source data isn’t in a format SQL Server recognises, or because the value itself is out‑of‑range (e.g., “2025‑02‑30”). Fortunately, the built‑in conversion functions CAST() and CONVERT() provide us with enough flexibility to clean up those problematic values without resorting to messy string manipulation.
Below we’ll look at the most common scenarios, show how to diagnose the issue, and demonstrate how to fix it.
Top 5 Data Conversion Errors in SQL Server and How to Avoid Them
Data conversion errors can be a frequent source of frustration when working with databases. And SQL Server is no exception. Such errors can interrupt workflows and lead to inconsistent results. While data conversion errors often happen during explicit conversions, they aren’t unique to this. Oftentimes the error can be due to an implicit conversion.
This article outlines five of the most common data conversion errors and provides practical steps to avoid them.
When to Use CONVERT() vs CAST() for Date Formatting in SQL Server
When formatting dates in SQL Server you may be wondering whether to use CONVERT() or CAST(). After all, both functions allow us to convert between data types. Let’s take a look at at these two functions and figure out when to use each one.
The Difference Between CAST() and TRY_CAST() in DuckDB
DuckDB offers two primary functions for type conversion: cast() and try_cast(). While they serve similar purposes, their behavior when handling invalid conversions differs significantly, which can greatly impact our data processing workflows.
Using TRY_CAST() to Handle Errors When Converting Between Data Types in DuckDB
Encountering errors while converting between data types can be frustrating when working with SQL databases like DuckDB. But it usually means that something’s wrong. In most cases these errors occur because we’re trying to perform an impossible conversion, like from a number to a date or something.
But sometimes errors can get in the way, especially when we’re trying to convert a bunch of values. Sometimes it would be better for the system to return NULL for such failed conversions than to return an error and mess up the whole operation. Fortunately, we can do this.
DuckDB CAST(): Converting Between Data Types
Most SQL databases provide a cast() function and DuckDB is no exception. The purpose of the cast() function is to convert a value from one data type to another. This can also be referred to as casting the value as the other data type.