ALTER FUNCTION CheckCUSIP(@CUSIP NVARCHAR(20))
RETURNS INT AS BEGIN
DECLARE @Check INT
IF RIGHT(@CUSIP,1) NOT BETWEEN '0' AND '9' BEGIN
SET @Check=-1
RETURN @Check
END
IF PATINDEX('%[^0-Z]%',@CUSIP)>0 BEGIN
SET @Check=-3
DECLARE @Sum INT=0,@Letter INT=1,@Char VARCHAR(1),@LetVal INT
WHILE @Letter<LEN(@CUSIP)
BEGIN
SET @Char=SUBSTRING(@CUSIP,@Letter,1)
SET @LetVal=((SELECT (CASE WHEN @Char BETWEEN '0' AND '9' THEN @Char ELSE ASCII(UPPER(@Char))-55END))
*(CASEWHEN @Letter%2=1 THEN 1 ELSE 2 END))
If @LetVal > 9 BEGIN
SET @LetVal =(@LetVal % 10)+(@LetVal / 10)
End
SET @Sum=@Sum+@LetVal
SET @Letter=@Letter+1
SET @Sum=(10 -(@Sum % 10))% 10
IF LEN(@CUSIP)<>9 BEGIN
SET @Check=-4
IF RIGHT(@CUSIP,1) BETWEEN '0' AND '9' BEGIN
SET @Check =(CASEWHEN RIGHT(@CUSIP,1)=@Sum THEN 1 ELSE 0 END)
