How to display Items that equal a value in one column and are not null in another

Question

Let's say I want to display all items in a table with following criteria how would i do this?

SELECT *
FROM TABLE
WHERE TABLE.COLUMN1 = 'example' AND TABLE.COLUMN2 != 'NULL'

I want it to display all values from COLUMN1. How does one go about this process in MS SQL?

Answer 1

SELECT *
FROM TABLE
WHERE TABLE.COLUMN1 = 'example' AND TABLE.COLUMN2 IS NOT NULL

NULL is an UNKNOWN value , you cannot use any Comparison Operators (= , <> , > , <) with it. you check for nulls like

ColumnName IS NULL    or ColumnName IS NOT NULL 

If you think about it , it makes sense, to compare two or more values, you need to know the values only then you can compare them, Since SQL Server considers a NULL to be an UNKNOWN value, you cannot really compare an unknown value to anything.

Answer 2

NULL values can be compared using IS [NOT] NULL in SQL server. Please check this .