Does SQL Server expand a view's sql inline during execution? -

let's have (hypothetical) table called table1 500 columns , there view called view1

 select column1, column2,..., column500, computedorforeignkeycolumn1,...       table1   inner join foreignkeytables ..... 

now, when execute

select column32, column56  view1 

which 1 of below 3 sql server turn into?

query #1:

select column32, column56       (select           column1, column2,..., column500, computedorforeignkeycolumn1,...                 table1       inner join           foreignkeytables ......) v 

query #2:

select column32, column56  table1 

query #3:

select column32, column56         (select column32, column56         table1) v 

the reason i'm asking have wide table , view sitting on top of (that inner joins bring texts foreign key ids) , can't figure out if sql server fetches columns , selects ones needed or fetches needed (while ignoring unnecessary joins etc)...if former view not best performance.

sql server query compilation can split phases:

1. parsing
2. binding
3. optimization

view resolution performed during binding. @ stage view reference replaced definition. @ point, unused view columns present.

the next stage optimization, bound syntax tree transformed execution plan. optimizer considers many kinds of manipulations on execution plan increase efficiency, , removing unused columns 1 of basic. @ point, unused column references removed.

so answer question, unused columns in view definition will not impact performance, since optimizer smart enough remove them.

note: answer assumes view not indexed. indexed views, resolution process works differently, , there view maintenance overhead updates of base tables.