On Fri, Sep 20, 2002 at 02:49:25PM +0200,
Henrik Steffen <steffen@city-map.de> wrote
a message of 113 lines which said:
> and if i insert into foo (foobar) values('bar') without
> explicitly inserting a value for bar, the bar column of this
> particular row will be empty. it's neither 't' nor 'f'.
Actually, it will be NULL. Unless you add a constraint NOT NULL to the
column.
> But I want to know, how I can select all rows which neither
> match 't' nor 'f' ? To perform an update like
>
> UPDATE foo SET bar='t' WHERE bar=null;
... WHERE bar IS NULL;
(It is a common SQL problem, the handling of NULL values. Read any
book about SQL.)