The unless prefix and suffix is used for creating a conditional clause which determines whether a statement or exit clause should be evaluated or not. It may be seen as a compact alternative to the full if..end if statement.
(Unless condition statement | exitstatement Unless condition )
The statement or the exitstatement will only be executed if condition is evaluated to False.
The unless prefix may be used on statements which already have one or several other statements, including additional when or unless prefixes.
|A logical expression evaluating to True or False.
|Any QlikView script statement except control statements.
|An exit for, exit do or exit sub clause or an exit script statement.
exit script unless A=1;
unless A=1 LOAD * from myfile.csv;
unless A=1 when B=2 drop table Tab1;