Where Not Exists In Table Only

[s2ncpgwx]

I'm trying load additional rows into a table while avoiding duplication with existing rows. See the demo load script below. The result in Tab 2 is:

F1 F3

A Large

B Small

The Where Not Exists clause is checking the entire field F1. Can it be forced to check only within Tab 2 so the end result is:

F1 F3

A Large

B Small

C Medium

Ie, a row for C is added but A and B are not duplicated? I have a workaround involving temporarily duplicating F1: is there a better approach?

[Tab 1]:
load *
inline
[F1, F2
A, Regular
B, Premium
C, Occasional];

[Tab 2]:
load *
inline
[F1, F3
A, Large
B, Small];

// Does not load (C, Medium) since C already exists in Field F1
concatenate([Tab 2])
load F1
,'Medium' as F3
resident [Tab 1]
where not exists(F1);

[Gysbert_Wassenaar · Accepted solution]

Your workaround is actually the best practice to deal with this issue.

[s2ncpgwx]

Thanks Gysbert.