# Create a new Function

CREATE FUNCTION FirstWord (@input varchar(1000))
RETURNS varchar(1000)
    DECLARE @output varchar(1000)
    SET @output = SUBSTRING(@input, 0, CASE CHARINDEX(' ', @input)
        WHEN 0 THEN LEN(@input) + 1
        ELSE CHARINDEX(' ', @input)

    RETURN @output

This example creates a function named FirstWord, that accepts a varchar parameter and returns another varchar value.

# Syntax

  • CREATE FUNCTION function_name ( [list_of_paramenters] ) RETURNS return_data_type AS BEGIN function_body RETURN scalar_expression END
  • # Parameters

    Argument Description
    function_name the name of function
    list_of_paramenters parameters that function accepts
    return_data_type type that function returs. Some SQL data type
    function_body the code of function
    scalar_expression scalar value returned by function

    # Remarks

    CREATE FUNCTION creates a user-defined function that can be used when doing a SELECT, INSERT, UPDATE, or DELETE query. The functions can be created to return a single variable or a single table.