Pormula question

[interface_eng]

 

After searching for student number
sign up or dropping out

1) Sign up : If there is already a Sign up in Sheet1, only the list of lectures (Sheet2) without values ​​is displayed in Sheet1.

2) Dropping out : Displays a list of lectures (Sheet2) with no values ​​in Sheet1.

How should I write the course type and formula or student number?

[AleksiAlkio]

Something like..

#1 - Sheet2[Lectrue] - SELECT(Sheet1[Lectrue],[Student Number]=[_THISROW].[YourColumnName])
#2 - SELECT(Sheet1[Lectrue],[Student Number]=[_THISROW].[YourColumnName])