I wonder why in the rule engine node lacks the comparison operator “Not equal” (e.g. <>, ~ =, ^=, …)
I used the following script within the Rule Engine node and it worked (use parentheses):
NOT ($column1$ = $column2$) => TRUE
The result is true for the last 2 rows as shown below.
If no rule matches, the outcome is a missing value.
Thank you, Cpadilla!
As I remember the parentheses at that position is optional, so NOT $column1$ = $column2$ => 2 would work the same. Though the NOT cannot be used in infix position, so $column1$ NOT = $column2$ is not allowed.
Regarding the non-existent not-equals operator: probably because there is not a single commonly used one.
<> is a standard SQL-92 operator; != is non standard, but most software companies implemented it.
Knime developers should take this into account.