Svein,

I appreciate your concern. I will try to explain why I'm using views.

It helps to concentrate calculated data and avoids a need to duplicate
the same expressions again. (structuring)
It allows to customize data representation and keep some information
secure. (administrative function).
It allows to hide using of non-standard or rare features like UDFs and
predefined variables. (portability).
It is designed for further selection. (structuring)

A virtual nature of view lets me imagine it as a hidden part of entire
'select' operator, that would be examined as a whole by optimizer. The
world would be easier if we have at least 'coalesce' function.

About your suggestion: I will remove PK from 'Reserves" table. I will
create another optimized view with Reserves table instead of using huge
'vOrderItems'.

Thank you very much.

Andrew