Why can't I compare an empty string?

Asked Sep 18 '14 at 15:54

Active Sep 18 '14 at 15:54

Viewed 12 times

This block

BEGIN
  IF 'foo' = '' THEN
    DBMS_OUTPUT.PUT_LINE('True');
  ELSE
    DBMS_OUTPUT.PUT_LINE('False');
  END IF;
END;

prints "False", as one would expect. But if the comparison is replaced with 'foo' <> '' or 'foo' != '', it still prints "False". Why would that be so? What is the proper way to check whether a string is empty?

asked Sep 18 '14 at 15:54

Colin P. Hill

1

Try checking against NULL instead. More information here: http://stackoverflow.com/a/7286239 – Robert Harvey Sep 18 '14 at 15:57
Can you try `length('foo') > 0` ? – ROMANIA_engineer Sep 18 '14 at 16:01
@RobertHarvey Well that answers that. Thanks – Colin P. Hill Sep 18 '14 at 16:06

Why can't I compare an empty string?

0 Answers0