# Conditional expression on tags that are often null? \[BEGINNER\] **URL:** \ **Category:** Ignition\ **Tags:** vision\ **Created:** [May 27, 2022, 4:54pm UTC](https://forum.inductiveautomation.com/t/conditional-expression-on-tags-that-are-often-null-beginner/60132 "2022-05-27T16:54:40Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![Mark\_Rzewnicki](https://avatars.discourse-cdn.com/v4/letter/m/278dde/32.png) [@Mark\_Rzewnicki](https://forum.inductiveautomation.com/u/Mark_Rzewnicki)\ **Post date:** [May 27, 2022, 4:54pm UTC](https://forum.inductiveautomation.com/t/conditional-expression-on-tags-that-are-often-null-beginner/60132/1 "2022-05-27T16:54:40Z")
Hello, I have a UDT containing multiple status integers with the same general meaning: 1 - Complete 2 - Warning 3 - On Hold If any one of the status ints is equal to 3, the “on hold” designation applies to the entire instance. I would like to add a boolean expression tag to this UDT that checks the values of all the status ints and evaluates as true if any of them is equal to 3. The expression I wrote basically looks like: {[.]StatusInt1} \> 2 || {[.]StatusInt2} \> 2 … || {[.]StatusIntN} \> 2 This works sometimes, but other times the boolean tag shows a red exclamation with “Error\_ExpressionEval” I think this is happening because the status ints are being set dynamically and the expression doesn’t like evaluating on a bunch of null values. Any ideas on how I can do this cleanly or a point in the right direction would be greatly appreciated! ---
**Author:** ![lrose](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/lrose/32/62724_2.png) [@lrose](https://forum.inductiveautomation.com/u/lrose)\ **Post date:** [May 27, 2022, 5:09pm UTC](https://forum.inductiveautomation.com/t/conditional-expression-on-tags-that-are-often-null-beginner/60132/2 "2022-05-27T17:09:40Z")
You can return a default value by using the `coalesce` expression. [https://docs.inductiveautomation.com/display/DOC81/coalesce](https://docs.inductiveautomation.com/display/DOC81/coalesce) I also might be tempted to do something more like: ```auto max({[.]StatusInt1,{[.]StatusInt2},...) = 3 ``` There are several ways to accomplish what you’re trying to do. ---
**Author:** ![pascal.fragnoud](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pascal.fragnoud/32/24728_2.png) [@pascal.fragnoud](https://forum.inductiveautomation.com/u/pascal.fragnoud)\ **Post date:** [May 27, 2022, 5:10pm UTC](https://forum.inductiveautomation.com/t/conditional-expression-on-tags-that-are-often-null-beginner/60132/3 "2022-05-27T17:10:01Z")
> [@Mark\_Rzewnicki](#): > > {[.]StatusInt1} \> 2 > [@Mark\_Rzewnicki](#): > > equal to 3 If it's `equal to 3`, use `= 3`. the `coaslesce` expression function will do what you want. If you use `coalesce(x, true)` and x is null, it will return true. ---
**Author:** ![Brandon\_Peterson](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/brandon_peterson/32/32960_2.png) [@Brandon\_Peterson](https://forum.inductiveautomation.com/u/Brandon_Peterson)\ **Post date:** [May 27, 2022, 5:24pm UTC](https://forum.inductiveautomation.com/t/conditional-expression-on-tags-that-are-often-null-beginner/60132/4 "2022-05-27T17:24:25Z")
Putting these two replies together, I think one of the following two solutions would work well for you: Use `coalesce` to “safety check” each `StatusInt` in the expression. It would look something like this: ```auto coalesce({[.]StatusInt1}, 0) = 3 || coalesce({[.]StatusInt2}, 0) = 3 || ... ``` Another possibility is to do this “safety check” in the expression for each `StatusInt` itself. You could, for example, say that the value `0` means the same thing as what `null` did before. That way, you’d only ever be dealing with non-null values, and your original solution would work. ```auto StatusInt1 -> coalesce(, 0) ``` ```auto {[.]StatusInt1} = 3 || {[.]StatusInt2} = 3 || ... ``` ---
**Author:** ![Mark\_Rzewnicki](https://avatars.discourse-cdn.com/v4/letter/m/278dde/32.png) [@Mark\_Rzewnicki](https://forum.inductiveautomation.com/u/Mark_Rzewnicki)\ **Post date:** [May 27, 2022, 5:27pm UTC](https://forum.inductiveautomation.com/t/conditional-expression-on-tags-that-are-often-null-beginner/60132/5 "2022-05-27T17:27:38Z")
Thanks to all! max(…) = 3 works like a charm :^D