What is the difference between if a and if a and not b

[dkanand86]

Hi,

Please can someone explain with a simple dataset merge and proc sql example the difference between following scenarios:

1. if a

2. if b

3. if a and not b

4. if not a and b

Thanks

[Reeza]

SQL Joins Explained (x-post r/SQL) : programming

1. R1C1

2. R1C3

3.R1C2

3. R1C4

[Astounding]

These are simple logical conditions, whether it's a DATA step, SQL, or a treatise by Aristotle.

Assuming that "a" and "b" can be either true or false:

if a ==> true whenever "a" is true, regardless of the value of "b"

if b ==> true whenever "b" is true, regardless of the value of "a"

if a and not b ==> true whenever "a" is true and "b" is false

if not a and b ==> true whenever "a" is false and "b" is true

In SAS programming, if "a" and "b" represent numeric amounts rather than comparisons, SAS considers 0 and missing to be false and any other value to be true.

Good luck.