t-sql

Troubleshooting Date Format Errors in SQL Server Imports

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Importing data into SQL Server is usually quite straightforward. That is, until you run into date and time formatting issues. Dates that look fine in a CSV, Excel, or flat file can suddenly throw errors or, worse, silently load with the wrong values. Since SQL Server is strict about how it interprets dates, mismatches between source file formats and SQL Server’s expectations are one of the most common headaches during imports.

This article looks at why these errors happen, what SQL Server expects, and how to troubleshoot these pesky date format issues.

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Fixing Multiple SELECT Expressions Errors in SQL Server

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If you’ve worked with SQL Server long enough, you’ve probably run into the dreaded “Only one expression can be specified in the select list when the subquery is not introduced with EXISTS” error. This error usually pops up when you try to use a subquery in a place where SQL Server expects a single value, but your query is returning multiple columns or multiple rows.

It’s a simple mistake, but it can be frustrating until you understand why it happens and how to fix it.

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How to Validate Column Data Types Before Inserting Data in SQL Server

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One of the most common causes of errors in SQL Server is trying to insert the wrong type of data into a column. If a column expects an integer but you push in a string, SQL Server will either throw an error or attempt an implicit conversion that may not work the way you expect. This is more common when data comes from external sources like APIs, flat files, or user inputs, where you don’t always control the formatting. Validating data types before inserting not only prevents runtime issues but also keeps your tables clean and predictable.

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How to Export SQL Server Query Results as JSON with FOR JSON AUTO

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SQL Server makes it surprisingly simple to generate JSON directly from a query. If you’ve ever had to send data to a web service, feed an API, or just save query results in a structured text format, JSON is a natural choice. Instead of writing complex formatting logic in your application, you can let SQL Server do the heavy lifting with the FOR JSON clause. And you can use the AUTO keyword to have the JSON formatted automatically by SQL Server.

In this article, we’ll look at how FOR JSON AUTO works, along with some examples to demonstrate its usage.

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Common Causes of “Multi-Part Identifier Could Not Be Bound” in SQL Server

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If you’ve worked with SQL Server for a while, you’ve probably run into the dreaded 4101 error that looks something like Msg 4104, Level 16, State 1, Line X: The multi-part identifier “X.Y” could not be bound.

It’s one of those vague errors that doesn’t immediately tell you what’s wrong. Basically SQL Server is complaining because it doesn’t know how to resolve the reference you wrote. This is usually a column or alias.

Let’s take a look at the most common causes, with examples to make them easier to spot.

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Split and Re-Aggregate Delimited Strings in SQL Server

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Working with delimited strings in SQL Server can be messy. Maybe you inherited a table where a column holds multiple values separated by commas, or you need to take a list and break it apart before putting it back together in some aggregated form. While best practice is to normalize data into proper relational tables, sometimes you don’t control the schema. Or perhaps you’re just solving a one-off reporting need.

This article walks through how to split delimited strings into rows, process them, and then re-aggregate them back into a single string, all within SQL Server.

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Handling Unix Timestamps in SQL Server

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Unix timestamps (also known as epoch time) are a simple way of representing a point in time: the number of seconds that have passed since 00:00:00 UTC on January 1, 1970 UTC. They’re popular in APIs, logs, and systems that need a compact, language-neutral way to store time.

If you’re working with SQL Server, you’ll almost certainly run into Unix timestamps eventually. Either you’re getting them from an external system or you need to produce them for one. Let’s walk through how to handle them in SQL Server.

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Understanding FORMATMESSAGE() in SQL Server

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When you’re working with SQL Server, sometimes you don’t just want to throw an error. Sometimes you want to build a message you can actually use elsewhere. That’s where FORMATMESSAGE() comes in. Instead of immediately printing a message like RAISERROR does, FORMATMESSAGE() gives you the formatted string back so you can decide what to do with it. This could include logging it, storing it, displaying it, or simply passing it along.

In simple terms, you can think of it as a way to take a predefined message from sys.messages (or even a custom string you provide) and turn it into a neatly formatted output. This can be quite handy when you need more control over how messages are handled in your SQL workflows.

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OPENJSON() vs JSON_VALUE() When Parsing JSON in SQL Server

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Working with JSON in SQL Server often comes down to choosing the right function for the job. Two of the most common options are OPENJSON() and JSON_VALUE(). Both are designed to pull data out of JSON documents, but they work in very different ways and are suited to different scenarios. Knowing when to use each one can save time and simplify your queries.

This article breaks down how OPENJSON() and JSON_VALUE() handle JSON parsing, what makes them different, and the situations where one might be a better fit than the other. Whether you are cleaning up nested JSON or just extracting a single value, understanding these functions will help you work more effectively with JSON data in SQL Server.

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