SQL Stored Proc - Correct any number of leading chars.

USE [DataProcessing]
GO
/****** Object:  StoredProcedure [dbo].[CorrectColumn]    Script Date: 09/06/2014 14:16:51 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO

ALTER PROCEDURE [dbo].[CorrectColumn] (@TableName NVARCHAR(25),
                                       @TargetColumn NVARCHAR(55),
                                       @TargetString NVARCHAR(55),
                                       @ReplacementString NVARCHAR(55)
                                       )

/*
=====================================
+++ PROCEDURE NAME: CorrectColumn +++
+++ AUTHORED BY: Kyle Korchak     +++
+++ DATE: 9-6-2014                +++
=====================================
+------------------------------------------+
¦~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~¦
¦------------------------------------------¦
¦ THIS STORED PROC IS USED TO TRUNCATE     ¦
¦ AND CORRECT THE CONTENTS OF A COLUMN     ¦
¦                     ¦
¦ IT IS WRITTEN IN A DYNAMIC STYLE TO MAKE ¦
¦ IF VERY VERSITILE. CAN BE USED ON MOST   ¦
¦ DATABASES, ALMOST ANY TABLE, REGARDLESS  ¦
¦ OF HOW THE TABLE IS DESIGNED.           ¦
¦                     ¦
¦ IN ADDITION TO THAT, IT CAN ALSO BE      ¦
¦ MODIFIED WITH VERY LITTLE WORK TO MAKE   ¦
¦ IT MORE CUSTOMIZED TO A PARTICULAR       ¦
¦ TABLE. FOR EXAMPLE, YOU CAN REMOVE THE   ¦
¦ VARIABLE FUNCTION OF:               ¦
¦      @TableName         ¦
¦      @TargetColumn          ¦
¦      @ReplacementString     ¦
¦                     ¦
¦ AND MAKE THIS FUNCTION IN A MECHANICAL   ¦
¦ MANNER THAT PERFECTLY AFFECTS YOUR OWN   ¦
¦ TABLE.                  ¦
¦------------------------------------------¦
¦FOR MORE NOTES PLEASE SEE BELOW ALL THE   ¦
¦CODE!                    ¦
+------------------------------------------+
*/

AS
BEGIN
    DECLARE @lenTargetString NVARCHAR(25)
    DECLARE @lenSourceString NVARCHAR(25)
    DECLARE @sqlUPDATE NVARCHAR(MAX)
    DECLARE @sqlSET NVARCHAR(MAX)
    DECLARE @sqlWHERE NVARCHAR(MAX)

-- COMPILE PARTS OF THE DYNAMIC SQL STRING
    SET @lenTargetString = LEN(@TargetString)
    SET @sqlUPDATE = N'UPDATE ' + @TableName
    SET @sqlSET =   N' SET ' + @TargetColumn + ' = ''' + @ReplacementString + ''' + SUBSTRING(' + @TargetColumn + ', ' + @lenTargetString + ', LEN(' + @TargetColumn + ')-' + @lenTargetString + ') '
    SET @sqlWHERE = ' WHERE ' + @TargetColumn + ' LIKE ''' + @TargetString + ''''

-- EXECUTE COMPOUND DYNAMIC SQL STRING
-- PRINT 'String being executed:' /* To debug remove leading double-dash. */
-- PRINT @sqlUpdate + ' ' + @sqlSET + ' ' + @sqlWHERE /* To debug remove leading double-dash. */
    EXEC (@sqlUpdate + ' ' + @sqlSET + ' ' + @sqlWHERE)

END