----- Original Message -----
> From: "David Lerer" <DLerer@stripped>
> Have you tried to set city = null (i.e. without the quotes)?
Spot on, I'd think.
NULL values are not a string with "NULL" in it - that's only what it looks like in query
results :-) An empty string ('') is to strings what 0 (zero) is for integers: it says "the
value of this field is nothing". NULL, on the other hand, means "the value of this field
is a total unknown", which is useful, for example, in a field 'quantity': zero is still a
valid, meaningful quantity; whereas you would use NULL to indicate that you simply do not
know the quantity.
It's a bit of a peculiar concept, but as David indicated, IS NULL will not match fields
set to the string "NULL" - as that is a string, not an unknown.
Another funny attribute of NULL is that NULL != NULL. There simply *is* nothing to
compare, so you cannot ever say it's equal.
Bier met grenadyn
Is als mosterd by den wyn
Sy die't drinkt, is eene kwezel
Hy die't drinkt, is ras een ezel