How to Efficiently Split Delimited Strings in T-SQL?

Efficiently Splitting Delimited Strings in T-SQL

This article explores efficient techniques for separating comma-delimited strings (e.g., "1,2,3,4,5") into individual rows within a T-SQL table or table variable. Two effective methods are detailed below:

Method 1: XML Parsing

This approach leverages T-SQL's XML parsing capabilities for a concise solution:

<code class="language-sql">DECLARE @xml xml, @str varchar(100), @delimiter varchar(10)

SET @str = '1,2,3,4,5,6,7,8,9,10,11,12,13,14,15'
SET @delimiter = ','
SET @xml = cast(('<X>'+replace(@str, @delimiter, '</X><X>')+'</X>') as xml)

SELECT C.value('.', 'varchar(10)') as value FROM @xml.nodes('X') as X(C)</code>

Method 2: Recursive CTE

For those preferring a recursive Common Table Expression (CTE) approach:

<code class="language-sql">DECLARE @str varchar(100), @delimiter varchar(10)

SET @str = '1,2,3,4,5,6,7,8,9,10,11,12,13,14,15'
SET @delimiter = ','

;WITH cte AS
(
    SELECT 0 a, 1 b
    UNION ALL
    SELECT b, CHARINDEX(@delimiter, @str, b) + LEN(@delimiter)
    FROM CTE
    WHERE b > a
)
SELECT SUBSTRING(@str, a,
CASE WHEN b > LEN(@delimiter) 
    THEN b - a - LEN(@delimiter) 
    ELSE LEN(@str) - a + 1 END) value      
FROM cte WHERE a > 0</code>

Both methods offer efficient string splitting, allowing for subsequent data processing and analysis. For more complex string manipulation, consult specialized T-SQL string functions and advanced techniques.

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