SQL Split String By Delimiter

How can I split a string into multiple parts based on a delimiter in SQL?

SQL doesn't have a built-in string splitting function. This concept explores common workarounds to achieve this using string functions like SUBSTRING, CHARINDEX, and recursive CTEs.

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Description

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Splitting strings by delimiters is a common task in SQL, but unlike some programming languages, SQL doesn't have a direct 'split' function. To achieve this, we need to leverage string manipulation functions. One common approach involves using functions like `SUBSTRING` and `CHARINDEX` to extract substrings based on the delimiter's position. Another method, particularly useful for handling multiple splits, is using a recursive Common Table Expression (CTE). This approach iteratively extracts substrings until the delimiter is no longer found. This allows for more dynamic and flexible string splitting, especially when dealing with varying numbers of substrings within a single string.

Why SQL Split String By Delimiter is important

Understanding string manipulation techniques like splitting is crucial for data cleaning and transformation tasks. It allows you to extract meaningful information from strings stored in your database, enabling more complex queries and data analysis.

SQL Split String By Delimiter Example Usage


-- Using SQL Server Management Studio (SSMS) to query data
-- Open SSMS, connect to your SQL Server instance
-- In the Object Explorer, expand your database
-- Right-click on the table you want to query and select 'New Query'
-- Enter your query (e.g., to select all columns from the 'Customers' table):

SELECT *
FROM Customers;

SQL Split String By Delimiter Syntax

Common Mistakes

Forgetting to handle cases where the delimiter is not present or is at the beginning or end of the string.
Using incorrect string functions or syntax, leading to errors or unexpected results.
Not considering potential edge cases, such as empty strings or strings with multiple consecutive delimiters.

Frequently Asked Questions (FAQs)

What SQL functions can I use to split a string when my database lacks a built-in SPLIT function?

Most relational databases let you combine SUBSTRING() with CHARINDEX() (or INSTR() / POSITION() depending on the dialect) to locate the delimiter and extract the left-most token. By repeatedly applying these two functions—or wrapping them in a loop or CTE—you can peel off each segment of the original string without relying on a proprietary SPLIT function.

When should I prefer a recursive CTE over simple SUBSTRING-based logic for string splitting?

If you only need the first or second token, a single pass with SUBSTRING() and CHARINDEX() is fine. But when the input contains an unknown or variable number of delimiters—like a comma-separated ID list—a recursive Common Table Expression shines. The CTE repeatedly finds the next delimiter, emits the token, trims the processed part, and continues until no delimiter remains, returning each piece as its own row. This approach is set-based, easy to integrate with joins, and scales better than nested scalar functions.

How can Galaxy’s AI Copilot accelerate writing split-by-delimiter queries?

Galaxy’s context-aware AI Copilot can auto-generate the entire recursive CTE or SUBSTRING()/CHARINDEX() pattern for you. Simply describe the source column and delimiter in natural language, and the Copilot suggests a ready-to-run query inside the editor. It also adapts the syntax to your database dialect, annotates each step for readability, and saves the snippet to a shared Collection so teammates can reuse or endorse it—no more copying SQL into Slack or Notion.