Difference between "column is null" and "column = null" in where clause in db2?

Question

I am getting different results when I run the query with above clause but not able to understand why. can any one explain what is the difference between the two clauses.

Answer 1

The result of column = null is unknown (null), since it can't be known what null really is. If you want to test for null and get a boolean value back you need to use is null. So, `column` is null is the correct syntax to use.

Answer 2

A comparison to null always evaluates to false, so column = null evaluates to false as well as column != null, independently of the value of column. If you want to actually check whether a value is null, you have to use column is null.