Question

I am working in Teradata with some descriptive data that needs to be transformed from a gerneric varchar(60) into the different field lengths based on the type of data element and the attribute value. So I need to take whatever is in the Varchar(60) and based on field ‘ABCD’ act on field ‘XYZ’. In this case XYZ is a varchar(3). To do this I am using CASE logic within my select. What I want to do is

eliminate all occurances of non alphabet/numeric data. All I want left are upper case Alpha chars and numbers.
In this case “Where abcd = ‘GROUP’ then xyz should come out as a ‘000’, ‘002’, ‘A’, ‘C’
eliminate extra padding
Shift everything Right

        abcd    xyz
1   GROUP   NULL
2   GROUP   $
3   GROUP   000000000000000000000000000000000000000000000000000000000000
4   GROUP   000000000000000000000000000000000000000000000000000000000002
5   GROUP   A
6   GROUP   C
7   GROUP   r

To do this I have tried TRIM and SUBSTR amongst several other things that did not work. I have pasted what I have working now, but I am not reliably working through the data within the select. I am really looking for some options on how to better work with strings in Teradata. I have been working out of the “SQL Functions, Operators, Expressions and Predicates” online PDF. Is there a better reference. We are on TD 13

SELECT abcd
        , CASE 
            -- xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
            WHEN abcd= 'GROUP'
                THEN(
                    CASE
                        WHEN SUBSTR(tx.abcd,60, 4) = 0
                            THEN (
                                    SUBSTR(tx.abcd,60, 3)
                                        )
                            ELSE
                                TRIM (TRAILING FROM tx.abcd)
                        END
                        )
            END AS abcd

FROM db.descr tx
WHERE tx.abcd IS IN ( 'GROUP')

The end result should look like this

    abcd    xyz
1   GROUP   000
2   GROUP   002
3   GROUP     A
4   GROUP     C

I will have to deal with approx 60 different “abcd” types, but they should all conform to the type of data I am currently seeing.. ie.. mixed case, non numeric, non alphabet, padded, etc..

I know there is a better way, but I have come in several circles trying to figure this out over the weekend and need a little push in the right direction.

Thanks in advance,
Pat

Answer 1

The SQL below uses the CHARACTER_LENGTH function to first determine if there is a need to perform what amounts to a RIGHT(tx.xyz, 3) using the native functions in Teradata 13.x. I think this may accomplish what you are looking to do. I hope I have not misinterpreted your explanation:

SELECT CASE WHEN tx.abcd = 'GROUP'
             AND CHARACTER_LENGTH(TRIM(BOTH FROM tx.xyz) > 3
            THEN SUBSTRING(tx.xyz FROM (CHARACTER_LENGTH(TRIM(BOTH FROM tx.xyz)) - 3))
            ELSE tx.abcd
       END
FROM db.descr tx;

EDIT: Fixed parenthesis in SUBSTRING