Projection
A projection follows the JSON syntax closely, it's basically a key-value pair. Except that FQL has several alternatives to acquire the value.
fieldname ':' value
FHIRpath expression
A value can be a FhirPath expression. Which means it can also be a string literal.
If the FHIRPath expression can lead to multiple values, you will get repeated fields in your selection. If hte FHirPath expression has nested structures , then your selection will have those nested structures too.
Example:
from Patient
select
namedata: name
Group
A projection value can also be a group { ... }
. This will however result in a json-like nested structure that is not usable for tabular output.