# Rule Engine for Multi Row formula

Hi All,

So i was trying on Just KNIME It Challenge (#4). Coming from a alteryx background, i always use != when i have to use not equals to.
So in this particular scenario i had used a lag column node in the previous step and then the rule engine node. But if i used \$A\$ = \$A(-1)\$ => 0
FALSE => 1
Then the True condition is getting displayed correctly but the false condition result is coming as ? Can someone tell the logic behind it?
For now i have used the reverse of the above logic
NOT \$A\$ = \$A(-1)\$ => 1
TRUE >= 0 which is giving perfect results but i still don’t understand the difference between those two.

RJ

But if i used \$A\$ = \$A(-1)\$ => 0
FALSE => 1
Then the True condition is getting displayed correctly but the false condition result is coming as ? Can someone tell the logic behind it?

Like the example code says:
`TRUE => "default outcome`

Your use of FALSE leads to a missing value, because FALSE has no useful meaning.

The code should be

``````\$A\$ = \$A(-1)\$ => 0
TRUE => 1
``````
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Ohh.
I was under the assumption that my equating of column A to column B is my True condition and anything else that doesn’t fall under that, will be under my false condition.
A little different i guess and may take some getting used to.

Can we use if else statements in the expression as i feel much more comfortable writing nested if else instead of this?

For this application, I’d recommend the Column Expressions node. The syntax would be javascript. See this post for details.

1 Like