STRING_SPLIT (Transact-SQL)

THIS TOPIC APPLIES TO: yesSQL Server (starting with 2016)yesAzure SQL DatabasenoAzure SQL Data Warehouse noParallel Data Warehouse

Splits the character expression using specified separator.

Note

The STRING_SPLIT function is available only under compatibility level 130. If your database compatibility level is lower than 130, SQL Server will not be able to find and execute STRING_SPLIT function. You can change a compatibility level of database using the following command:
ALTER DATABASE DatabaseName SET COMPATIBILITY_LEVEL = 130

Note that compatibility level 120 might be default even in new Azure SQL Databases.

Topic link icon Transact-SQL Syntax Conventions

Syntax

STRING_SPLIT ( string , separator )  

Arguments

string
Is an expression of any character type (i.e. nvarchar, varchar, nchar or char).

separator
Is a single character expression of any character type (e.g. nvarchar(1), varchar(1), nchar(1) or char(1)) that is used as separator for concatenated strings.

Return Types

Returns a single-column table with fragments. The name of the column is value. Returns nvarchar if any of the input arguments are either nvarchar or nchar. Otherwise returns varchar. The length of the return type is the same as the length of the string argument.

Remarks

STRING_SPLIT takes a string that should be divided and the separator that will be used to divide string. It returns a single-column table with substrings. For example, the following statement SELECT value FROM STRING_SPLIT('Lorem ipsum dolor sit amet.', ' '); using the space character as the separator, returns following result table:

value
Lorem
ipsum
dolor
sit
amet.

If the input string is NULL, the STRING_SPLIT table-valued function returns an empty table.

STRING_SPLIT requires at least compatibility mode 130.

Examples

A. Split comma separated value string

Parse a comma separated list of values and return all non-empty tokens:


DECLARE @tags NVARCHAR(400) = 'clothing,road,,touring,bike'  

SELECT value  
FROM STRING_SPLIT(@tags, ',')  
WHERE RTRIM(value) <> '';  

STRING_SPLIT will return empty string if there is nothing between separator. Condition RTRIM(value) <> '' will remove empty tokens.

B. Split comma separated value string in a column

Product table has a column with comma-separate list of tags shown in the following example:

ProductId Name Tags
1 Full-Finger Gloves clothing,road,touring,bike
2 LL Headset bike
3 HL Mountain Frame bike,mountain

Following query transforms each list of tags and joins them with the original row:

SELECT ProductId, Name, value  
FROM Product  
    CROSS APPLY STRING_SPLIT(Tags, ',');  

Here is the result set.

ProductId Name value
1 Full-Finger Gloves clothing
1 Full-Finger Gloves road
1 Full-Finger Gloves touring
1 Full-Finger Gloves bike
2 LL Headset bike
3 HL Mountain Frame bike
3 HL Mountain Frame mountain

C. Aggregation by values

Users must create a report that shows the number of products per each tag, ordered by number of products, and to filter only the tags with more than 2 products.

SELECT value as tag, COUNT(*) AS [Number of articles]  
FROM Product  
    CROSS APPLY STRING_SPLIT(Tags, ',')  
GROUP BY value  
HAVING COUNT(*) > 2  
ORDER BY COUNT(*) DESC;  

D. Search by tag value

Developers must create queries that find articles by keywords. They can use following queries:

To find products with a single tag (clothing):

SELECT ProductId, Name, Tags  
FROM Product  
WHERE 'clothing' IN (SELECT value FROM STRING_SPLIT(Tags, ','));  

Find products with two specified tags (clothing and road):


SELECT ProductId, Name, Tags  
FROM Product  
WHERE EXISTS (SELECT *  
    FROM STRING_SPLIT(Tags, ',')  
    WHERE value IN ('clothing', 'road');  

E. Find rows by list of values

Developers must create a query that finds articles by a list of ids. They can use following query:

SELECT ProductId, Name, Tags  
FROM Product  
JOIN STRING_SPLIT('1,2,3',',')   
    ON value = ProductId;  

This is replacement for common anti-pattern such as creating a dynamic SQL string in application layer or Transact-SQL, or by using LIKE operator:

SELECT ProductId, Name, Tags  
FROM Product  
WHERE ',1,2,3,' LIKE '%,' + CAST(ProductId AS VARCHAR(20)) + ',%';  

See Also

String Functions (Transact-SQL)
SUBSTRING (Transact-SQL)