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LEFT (Transact-SQL)

 

THIS TOPIC APPLIES TO: yesSQL Server (starting with 2008)yesAzure SQL DatabaseyesAzure SQL Data Warehouse yesParallel Data Warehouse

Returns the left part of a character string with the specified number of characters.

Topic link icon Transact-SQL Syntax Conventions

-- Syntax for SQL Server, Azure SQL Database, Azure SQL Data Warehouse, Parallel Data Warehouse  
  
LEFT ( character_expression , integer_expression )  

character_expression
Is an expression of character or binary data. character_expression can be a constant, variable, or column. character_expression can be of any data type, except text or ntext, that can be implicitly converted to varchar or nvarchar. Otherwise, use the CAST function to explicitly convert character_expression.

integer_expression
Is a positive integer that specifies how many characters of the character_expression will be returned. If integer_expression is negative, an error is returned. If integer_expression is type bigint and contains a large value, character_expression must be of a large data type such as varchar(max).

The integer_expression parameter counts a UTF-16 surrogate character as one character.

Returns varchar when character_expression is a non-Unicode character data type.

Returns nvarchar when character_expression is a Unicode character data type.

When using SC collations, the integer_expression parameter counts a UTF-16 surrogate pair as one character. For more information, see Collation and Unicode Support.

A. Using LEFT with a column

The following example returns the five leftmost characters of each product name in the Product table of the AdventureWorks2012 database.

SELECT LEFT(Name, 5)   
FROM Production.Product  
ORDER BY ProductID;  
GO  

B. Using LEFT with a character string

The following example uses LEFT to return the two leftmost characters of the character string abcdefg.

SELECT LEFT('abcdefg',2);  
GO  

Here is the result set.

--   
ab   
  
(1 row(s) affected)  

C. Using LEFT with a column

The following example returns the five leftmost characters of each product name.

-- Uses AdventureWorks  
  
SELECT LEFT(EnglishProductName, 5)   
FROM dbo.DimProduct  
ORDER BY ProductKey;  

D. Using LEFT with a character string

The following example uses LEFT to return the two leftmost characters of the character string abcdefg.

-- Uses AdventureWorks  
  
SELECT LEFT('abcdefg',2) FROM dbo.DimProduct;  

Here is the result set.

--   
ab  

CAST and CONVERT (Transact-SQL)
Data Types (Transact-SQL)
String Functions (Transact-SQL)

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