Pormula question

AppSheet AppSheet Q&A
1

슬라이드1.PNG
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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?

2

Something like..

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