How to Pass Multiple Strings in One Function Parameter in SQL Server

Learn effective methods to pass multiple values to a single parameter in SQL Server. Explore solutions for both SQL Server 2016 and earlier versions!
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How to Pass Multiple Strings in One Function Parameter in SQL Server

SQL Server is a powerful relational database management system, but sometimes you may face a challenge when trying to pass multiple values to a single parameter in a function. This is a common requirement, especially when dealing with operations that involve lists of items, such as filtering records based on multiple names.

The Problem Statement

Imagine you have a table called Students with student names, and you want to create a function that can count how many students have names that match a set of names passed as a single string parameter. For example, you want to call a function like this:

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

This task might seem tricky at first because SQL Server's parameters typically handle single values. However, there are effective strategies to tackle this problem!

Solution Overview

We can achieve the desired functionality by leveraging different approaches depending on the version of SQL Server you are using. Below, we’ll break down the solutions tailored for SQL Server 2016 and later as well as older versions.

For SQL Server 2016 and Later: Using string_split

If you are using SQL Server 2016 or later versions, the string_split function is a fantastic built-in feature that can help you easily convert a delimited string into a table format. Here’s how you can implement it:

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

Explanation of the Code:

Function Definition: The function GetCount accepts a single VARCHAR parameter.

Using string_split: The string is split into rows using string_split(@ name, ',').

Count Condition: The function counts how many times the names in Students match the ones provided in the parameter.

For Older Versions of SQL Server: Manual String Splitting

If you're using an older version of SQL Server that does not support string_split, you can implement a workaround using XML parsing. Here’s a method to achieve that:

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

Explanation of the Code:

XML Manipulation: It converts the comma-separated string into XML format, allowing us to use XML nodes to split it into multiple values.

CROSS APPLY: This construct is used to combine the rows returned by the XML parsing with the Students table, enabling the matching process for counting.

Conclusion

Passing multiple strings as a single parameter in SQL Server can be accomplished effectively using the methods mentioned above. If you're working with SQL Server 2016 or newer, utilize string_split for a straightforward approach. However, if you're on an older version, XML parsing remains a powerful alternative.

By mastering these techniques, you can confidently manipulate and query your data in a more efficient way.

If you have any questions or need further assistance, feel free to leave a comment!