Email Validation Function

>>Script Language and Platform: MSSQL
This function checks for invalid characters, and some basic format.
Since SQL can’t use regular expressions, it cannot do a thorough validation, but this function DOES handle the minimum.
If the email is valid, it returns 1, if not 0.

*ex.
This is to delete invalid emails

DELETE FROM address
WHERE master.dbo.EMAILVALIDATE(email) = 0

Author: Jimmy Hattori

CREATE FUNCTION EMAILVALIDATE (@email varChar(100))
RETURNS int
AS
BEGIN
DECLARE @invalChars varchar(5),@valid int,@badChar varchar(1),@atPos
int,@periodPos int
SET @valid = 1
SET @invalChars = ‘ /:,;’
–Check to see if it’s blank
IF len(ltrim(rtrim(@email))) = 0
   SET @valid = 0
ELSE
  	–Loop invalid characters to see if it exists in email
	WHILE len(@invalChars) > 0
	   BEGIN
		SET @badChar = substring(@invalChars,1,1)
		IF(charindex(@badChar,@email) > 0)
		   –If invalid character was found, return 0 to invalidate
		   SET @valid = 0
		SET @invalChars = replace(@invalChars,@badChar,”)
	   END
	–Check to see if “@” exists.
	SET @atPos = charindex(‘@’,@email,1)
	IF @atPos = 0
	   SET @valid = 0
 	–Check to see if extra “@” exists after 1st “@”.
	IF charindex(‘@’,@email,@atPos+1) > 0
	   SET @valid = 0
	SET @periodPos = charindex(‘.’,@email,@atPos)
	IF @periodPos = 0
	   SET @valid = 0
	IF (@periodPos+3) > len(@email)
	   SET @valid = 0
	RETURN (@valid)
END

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