On Nov 27, 2007, at 21:04 , Gera Mel Handumon wrote:
I encounter an error if i use NULLIF with timestamp with time zone.
eq. dbtime=nullif(mytime,'')
i want to null the value of field DBTIME if the variable mytime=" "
DBTIME ="timestamp with time zone" datatype
error: column DBTIME is of type timestamp with time zone but
expression is of type text.
I believe the reason is that '' is not a valid timestamp value: think
of it this way:
IF mytime = '' THEN
mytime := NULL;
END IF;
The first thing it needs to do is compare the mytime value with ''.
As '' is not a valid timestamp value, it may be casing mytime to
text. You'll run into problems if you're assigning a text value to a
timestamp field (which happens after the initial comparison--and the
cast--are done.)
I think you may need to handle this is you middleware, or handle the
IF THEN explicitly in a function. Maybe CASE would work:
CASE WHEN mytime = '' THEN NULL
ELSE CAST(mytime AS TIMESTAMP)
END
Michael Glaesemann
grzm seespotcode net
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