Dec 4, 2009 · The expression "NULL = NULL" evaluates to NULL, but is actually invalid in SQL; yet ORDER BY treats NULLs as equal (whatever they precede or follow "regular" values is left …

In Java I am told that when doing a null check one should use == instead of .equals(). What are the reasons for this?

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 null check will be at least a thousand times faster (probably many thousands). For the path of execution to get into the catch block an exception has to have been raised which means …

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

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

In other words, a null pointer is a pointer of any type pointing at a well-defined "nowhere". Any pointer can turn into a null pointer when it is assigned a null pointer constant. The standard …

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 …