I'm sure there's more elegant ways of doing this but here's one option.
(Also, it might be easier just creating a pivot table in the front end with the Application field as a dimension as well and set it to horizontal.)
LOAD * INLINE [
if(index(AppString,'App1')>0,'Y') as App1,
if(index(AppString,'App2')>0,'Y') as App2,
if(index(AppString,'App3')>0,'Y') as App3;
Concat(Application, ';') as AppString
group by CustomerNumber;
Drop table T1;
I'm glad Johannes' solution worked for you. It's nice and simple.
I wanted to make a note that the general solution to this problem is "Generic Load". Especially useful if you have a variable number of AppN values. See