Question

**UPDATED with a better example

Let’s have two statements

1. (value > 15)
2. (value > 25)

And a list of items with the following values

• 10
• 20
• 30

This is what a truth table would give

Item  Value  (value > 15)  (value > 25)
----  -----  ------------  ------------
1     10     FALSE         FALSE
2     20     TRUE          FALSE
3     30     TRUE          TRUE

Example 1

Where ALL of the following are TRUE
   value > 15
   value > 25

This one is easy and we get the following

Where (value > 15) AND (value > 25)

The result is then a single value of 30

Example 2

Where NONE of the following are TRUE
   value > 15
   value > 25

This is where I am not sure of what to generate.

This would be “simple” as it is only a NOT of the whole expression

Where NOT ((value > 15) AND (value > 25))

However, the result is then two values (10 and 20)

From what someone would think of NONE of the two statements would be something like:

Where NOT ((value > 15) OR (value > 25))

And the result would be that 10 is returned.

What is the correct meaning of NONE here?

Answer 1

You can represent “none of (a, b, etc) is true” by either

(NOT a) AND (NOT b) AND (NOT etc) 

or

NOT (a OR b OR etc)

Either will work.

In your case, you could say NOT ((value > 15) OR (value > 25)). Only 10 matches.