How to create a Key Figure inside CDS View

Hello together,

to be able to use a Query in SAP Analytics Cloud via Live Data Connection there must be a key figure (of any type) inside the Query.

Can we create any type of calculation to create a key figure in the CDS View (that is below the query). Any kinf of key figure would be ok. We would like to create a simple counter that counts the amount of lines inside the table but we could not archive to do successfull.

BR/