Mar 6, 2012 · The reasoning is that a null means "unknown", so the result of any comparison to a null is also "unknown". So you'll get no hit on rows by coding where my_column = null. SQL …

Sep 21, 2021 · The only difference (besides the syntax) is, that the compiler guarantees that no user-overloaded operator is called when using is not null instead of != null (or is null instead of …

May 1, 2010 · Understanding the difference between “IS NULL” and “= NULL” When a variable is created in SQL with the declare statement it is created with no data and stored in the variable …

And then == null does a perfect job, because it covers exactly those 2 values. (i.e. == null is equivalent to === null && === undefined) In exceptional cases you do want a clear distinction …

Apr 14, 2011 · 135 NULL has no value, and so cannot be compared using the scalar value operators. In other words, no value can ever be equal to (or not equal to) NULL because NULL …

The title of this bug says "check for undefined or null", but the question itself checks for undeclared or null.

Jul 20, 2010 · How do I refer to the null object in Python?

So if you don't need to support the difference between empty and null/absent string you may also consider the empty parameter as null. If instead you want to recreate point 4. of JSON …

89 NOT IN returns 0 records when compared against an unknown value Since NULL is an unknown, a NOT IN query containing a NULL or NULL s in the list of possible values will …

Apr 20, 2009 · I want to have a unique constraint on a column which I am going to populate with GUIDs. However, my data contains null values for this columns. How do I create the constraint …