The generic projection
The generic projection (
select *) is used to include one column for every visible variable in the pattern component.
The order in which the columns are returned is not specified in the SPARQL standard and is implementation-specific. Often, columns are returned in the order in which the corresponding variables appear for the first time inside the pattern component, but this is not guaranteed. If the order of the columns is important, it is more robust to specify the variables explicitly.