Feb 16, 2019 · Basically, null! applies the ! operator to the value null. This overrides the nullability of the value null to non-nullable, telling the compiler that null is a "non-null" type.

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 …

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 …

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

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 …

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

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 …

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 …

Sep 6, 2017 · Comparing NULL with anything yields a NULL. NULL is part of trinary logic: TRUE, FALSE, and NULL. -- These are all NULL. select NULL > -1, NULL < -1, NULL = NULL, NULL …

But in this case only null and undefined are loosely equal to each other, therefore != null will return false for either of the two value, true for everything else. typeof input !== "undefined" Here the …