The IS NULL and IS NOT NULL operators are very useful in verifying if the returned value is a NULL type, or a valid one. Sometimes these NULL values will result in errors if not filtered properly and that is where it all comes from. The most basic syntax involving an IS NULL operator looks like this:

Syntax

SELECT * FROM count_table WHERE count IS NULL;

Naturally to find records which counts are not NULL, the following example will do:

SELECT * FROM count_table WHERE count IS NOT NULL;

Both are ways are recommended for NULL value verification, and the classic arithmetical operations will not work. For instance:

SELECT * FROM count_table WHERE count = NULL;

Or:

SELECT * FROM count_table WHERE count != NULL;