Try this:
SELECT CASE
WHEN btrim(' A string', ' ') = '' OR <field-name> IS NULL
THEN NULL
ELSE 6
END AS type_id;
-----Original Message-----
From: pgsql-general-owner@xxxxxxxxxxxxxx
[mailto:pgsql-general-owner@xxxxxxxxxxxxxx]On Behalf Of Bruno BAGUETTE
Sent: Friday, September 09, 2005 4:45 AM
To: pgsql-general@xxxxxxxxxxxxxx
Subject: Problem using NULLIF in a CASE expression
Hello,
I have a problem using NULLIF inside a CASE expression.
I explain the goal of my query : I have a table where there is two
fields : one varchar field and one INT8 field.
When the varchar field is empty I have to display the INT8 field.
If the varchar field is not empty I have to display a NULL value (even
if the INT8 field contains something).
BUT : that table is used by several applications and theses applications
does not always store NULL in the varchar field. Some applications store
an empty string '', or stores <space> char(s).
SO, I have to do a btrim and to get a NULL value when I just have ''
after the btrim.
I wrote another (and quite shorter!) SQL query to resume the problem :
SELECT CASE NULLIF(btrim(' A string', ' '), '')
WHEN NOT NULL
THEN NULL
ELSE 6
END AS type_id;
ERROR: operator does not exist: text = boolean
HINT: No operator matches the given name and argument type(s). You may
need to add explicit type casts.
Why this query does not accept the NULLIF ?
What can I do to solve that problem ?
Thanks in advance !
Bruno BAGUETTE.
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