Compare two list

[NAM_LI]

Hi, I have two table in my appsheet, the first table has the column of Room is ordered, it value is ref type which references to the second table which has the column of Room List (Enum type). I want to compare two table and show me which room isn’t being ordered.

[Suvrutt_Gurjar]

Please take a look at

help.appsheet.com

List Subtraction

Subtract lists to produce another containing only the unique items of the first list that aren't also in the second.

help.appsheet.com

List Expressions

List expressions use and/or produce lists of values.

[NAM_LI]

I tried this function in Valid if: ({SELECT(Table 1[Room list])} - {SELECT(Table 2[Room is ordered ])})
And it showed “ LIST has elements of mismatched types appsheet”

Room is orderd column value (Ref type) is ref of Room list column value (Text type)

I don’t know what is the problem. Please help me out. Thanks!

[Steve · Accepted solution]

NAM_LI:

Valid if: ({SELECT(Table 1[Room list])} - {SELECT(Table 2[Room is ordered ])})

There is nothing correct with that expression. I STRONGLY encourage you to spend more time reading the available documentation on expressions.