How to use decode for this

Question

Hi All
I have one table called agreementproductkey and some columns namely Agreementproductid, keytext, fliename etc.
There is some condition if agreement product id in not null and keytext field and fileaname field is null then i need to display the value as "NO FILE"
This what i tried
select decode(keytext || ' | ' || filename,null,'No File',keytext || filename) display_value, id return_value
from agreementproductkey
where agreementproductid = 3173
But i didnt get the NO FILE when key text field and filename field is null for this agreementproductid.
Thanks & Regards
Srikkanth.M

Answer 1

Hi Srikkanth,
In the decode part, you have concatenated keytext and filename using '|' due to which it will never evaluate to null, and hence 'NOFILE' will never be displayed. CASE is a better option instead of DECODE.
SQL> CREATE TABLE t (agreementid NUMBER, keytext VARCHAR2(10), filename VARCHAR2(10));
Table created
SQL> INSERT INTO t VALUES (123, 'ABC', 'ABCFile');
1 row inserted
SQL> INSERT INTO t VALUES (123, NULL, 'XYZFile');
1 row inserted
SQL> INSERT INTO t VALUES (123, 'PQR', NULL);
1 row inserted
SQL> INSERT INTO t VALUES (123, NULL, NULL);
1 row inserted
SQL> SELECT agreementid, keytext, filename,
  2         DECODE(agreementid, NULL, 'AGREEMENT NULL', DECODE(keytext || filename, NULL, 'NO FILE', 'FILE PRESENT'))
  3    FROM t;
AGREEMENTID KEYTEXT    FILENAME   DECODE(AGREEMENTID,NULL,'AGREE
        123 ABC        ABCFile    FILE PRESENT
        123            XYZFile    FILE PRESENT
        123 PQR                   FILE PRESENT
        123                       NO FILE
SQL> Regards
Ameya