patindex-transact-sql.md

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PATINDEX (Transact-SQL)	PATINDEX (Transact-SQL)	MikeRayMSFT	mikeray	07/19/2016	sql	t-sql	reference	PATINDEX PATINDEX_TSQL	first occurrence of pattern [SQL Server] searches [SQL Server], pattern starting position starting position of patten search pattern searching [SQL Server] PATINDEX function	TSQL	>= aps-pdw-2016 || = azuresqldb-current || = azure-sqldw-latest || >= sql-server-2016 || >= sql-server-linux-2017 || = azuresqldb-mi-current||=fabric

PATINDEX (Transact-SQL)

[!INCLUDE sql-asdb-asdbmi-asa-pdw-fabricse-fabricdw]

Returns the starting position of the first occurrence of a pattern in a specified expression, or zero if the pattern is not found, on all valid text and character data types.

:::image type="icon" source="../../includes/media/topic-link-icon.svg" border="false"::: Transact-SQL syntax conventions

Syntax

PATINDEX ( '%pattern%' , expression )  

Arguments

pattern
Is a character expression that contains the sequence to be found. Wildcard characters can be used; however, the % character must come before and follow pattern (except when you search for first or last characters). pattern is an expression of the character string data type category. pattern is limited to 8000 characters.

Note

While traditional regular expressions are not natively supported in [!INCLUDEssNoVersion], similar complex pattern matching can be achieved by using various wildcard expressions. See the String Operators documentation for more detail on wildcard syntax.

expression
Is an expression, typically a column that is searched for the specified pattern. expression is of the character string data type category.

Return Types

bigint if expression is of the varchar(max) or nvarchar(max) data types; otherwise int.

Remarks

If either pattern or expression is NULL, PATINDEX returns NULL.

The starting position for PATINDEX is 1.

PATINDEX performs comparisons based on the collation of the input. To perform a comparison in a specified collation, you can use COLLATE to apply an explicit collation to the input.

Supplementary Characters (Surrogate Pairs)

When using SC collations, the return value will count any UTF-16 surrogate pairs in the expression parameter as a single character. For more information, see Collation and Unicode Support.

0x0000 (char(0)) is an undefined character in Windows collations and cannot be included in PATINDEX.

Examples

A. Simple PATINDEX example

The following example checks a short character string (interesting data) for the starting location of the characters ter.

SELECT position = PATINDEX('%ter%', 'interesting data');  

[!INCLUDEssResult]

position
--------
3

B. Using a pattern with PATINDEX

The following example finds the position at which the pattern ensure starts in a specific row of the DocumentSummary column in the Document table in the [!INCLUDEssSampleDBnormal] database.

SELECT position = PATINDEX('%ensure%',DocumentSummary)  
FROM Production.Document  
WHERE DocumentNode = 0x7B40;  
GO   

[!INCLUDEssResult]

position
--------  
64  

If you do not restrict the rows to be searched by using a WHERE clause, the query returns all rows in the table and reports nonzero values for those rows in which the pattern was found, and zero for all rows in which the pattern was not found.

C. Using wildcard characters with PATINDEX

The following example uses % and _ wildcards to find the position at which the pattern 'en', followed by any one character and 'ure' starts in the specified string (index starts at 1):

SELECT position = PATINDEX('%en_ure%', 'Please ensure the door is locked!');  

[!INCLUDEssResult]

position
--------  
8  

PATINDEX works just like LIKE, so you can use any of the wildcards. You do not have to enclose the pattern between percents. PATINDEX('a%', 'abc') returns 1 and PATINDEX('%a', 'cba') returns 3.

Unlike LIKE, PATINDEX returns a position, similar to what CHARINDEX does.

D. Using complex wildcard expressions with PATINDEX

The following example uses the [^] string operator to find the position of a character that is not a number, letter, or space.

SELECT position = PATINDEX('%[^ 0-9A-Za-z]%', 'Please ensure the door is locked!'); 

[!INCLUDEssResult]

position
--------
33

E. Using COLLATE with PATINDEX

The following example uses the COLLATE function to explicitly specify the collation of the expression that is searched.

USE tempdb;  
GO  
SELECT PATINDEX ( '%ein%', 'Das ist ein Test'  COLLATE Latin1_General_BIN) ;  
GO  

[!INCLUDEssResult]

position
--------
9

F. Using a variable to specify the pattern

The following example uses a variable to pass a value to the pattern parameter. This example uses the [!INCLUDEssSampleDBnormal] database.

DECLARE @MyValue VARCHAR(10) = 'safety';   
SELECT position = PATINDEX('%' + @MyValue + '%', DocumentSummary)   
FROM Production.Document  
WHERE DocumentNode = 0x7B40;  

[!INCLUDEssResult]

position
--------  
22

See Also

LIKE (Transact-SQL)
CHARINDEX (Transact-SQL)
LEN (Transact-SQL)
Data Types (Transact-SQL)
String Functions (Transact-SQL)
(Wildcard - Character(s) to Match) (Transact-SQL)
(Wildcard - Character(s) Not to Match) (Transact-SQL)
_ (Wildcard - Match One Character) (Transact-SQL)
Percent character (Wildcard - Character(s) to Match) (Transact-SQL)