Thanks Tomas.... Understood... My bad.... Was just not looking at that aspect
Thanks once again, Regards, Jitendra On Wed, 11 Nov 2020 at 16:17, Tomas Vondra <tomas.von...@enterprisedb.com> wrote: > > On 11/11/20 10:06 AM, Jitendra Loyal wrote: > > Thanks Nikolay > > > > I read that but is there a way to meet the above requirement. And I will > > like to add that IS NULL and IS NOT NULL should evaluate to true/false. > > These operators are made for this and should not be returning NULL. > > > > This has nothing to do with IS [NOT] NULL, it's the first part of the > expression (b = TRUE) causing trouble. Essentially, the constraint > > (b = true) and (c is not null) > > is evaluated in two steps. First we evaluate the two parts individually, > and for (null, true) the results would look like this: > > (b = true) => null > (c is not null) => true > > and then we combine those results using 'AND' > > null AND true => null > > which is considered as if the constraint matches. If you want to handle > NULL for the first expression, you may do this, for example: > > (b it not null and b = true) and (c is not null) > > Or something like that. > > > regards > > -- > Tomas Vondra > EnterpriseDB: http://www.enterprisedb.com > The Enterprise PostgreSQL Company >
