From: | Liz Bartlett <khyri(at)idyllmtn(dot)com> |
---|---|
To: | pgsql-novice(at)hub(dot)org |
Subject: | Re: isnull or coalesce isn't working |
Date: | 2000-06-05 03:36:36 |
Message-ID: | 3.0.5.32.20000604203636.00992cf0@mail.idyllmtn.com |
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Thread: | |
Lists: | pgsql-novice |
>HI
>just started using postgres I want to do a select like the following.
>I have a table with two columns a and b, where sometimes data are missing.
>I want to do:
>SELECT ifnull(a,b) FROM table;
>
>==>ERROR: No such function 'ifnull' with the specified attributes
>
>tried the same thing with isnull and coalesce, same error.
I would try:
SELECT a, b FROM table WHERE (a ISNULL) OR (b ISNULL);
On a related note:
I have a table with a column of type LOGICAL. Some rows have 't', some
have 'f' and some have a NULL value.
I wanted to select all the rows that were not TRUE.
Using a WHERE clause of feespaid != 't' only returned the rows where
the value was 'f'. (As did other variations of a single condition,
such as NOT(feespaid = 't').)
In the end, I had to add in a second check for the NULL value:
SELECT entryid FROM entriesspring2000 WHERE ((feespaid != 't') OR (feespaid ISNULL))
This to me seems counterintuitive. Is there any way I can ask for
the rows that do not have a TRUE value without having two conditions?
--Liz
----------------------------------------------------------------------
Liz Bartlett*http://www.khyri.com/ 110 E. Wilshire Ave.#G-1
Idyll Mountain Internet*http://www.idyllmtn.com/ Fullerton, CA 92832
Virtual Dog Show Co-ordinator*http://www.dogshow.com/ (714) 526-5656
Tibetan Mastiff Web Site*http://www.tibetanmastiffs.com/
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