I have three tables: MasterList, MasterListLabels, and Projects. 

MasterList has a field called "Type" that is linked to MasterListLabels.

When I add a record to the Projects table, I click on a button to create a record in the MasterList table, and in that record I need to populate the "Type" field that is linked to MasterListLabels. This code works:

let m := (create MasterList);

m.(Type := 34);      // 34 is the relevant record ID in the MasterListLabels table 

However, I don't want to specify "34" in my code, I want to use a variable. But I have not been able to figure out how to define that variable. I have tried the following, but none of them work - all of them return null or give an error that 'thistype' returns multiple values:

let thistype := (select MasterListLabels['Label' = "Project"].Id);

m.(Type := thistype)

--

let thistype := (select MasterListLabels['Label' = "Project"].Id);

m.(Type := number(thistype))

--

let thistype := number((select MasterListLabels['Label' = "Project"].Id));

m.(Type := thistype)

--

let thistypepre := (select MasterListLabels['Label' = "Project"]);

let thistype := number(thistypepre.Id);

m.(Type := thistype)

Is there a way to make this work? Thanks!