SQL Lag() in SPARQL

Question

I was wondering if there is a way to get the functionality of SQL LAG() in my SPARQL query. More specifically, I have a set of states like

 p:start "2014-05-23T10:20:13+05:30"^^xsd:dateTime
 p:start "2014-06-23T10:20:13+05:30"^^xsd:dateTime
 p:start "2014-07-23T10:20:13+05:30"^^xsd:dateTime

And I want to find the duration of each state. The duration of each state, lets say state A, can be computed by subtracting the start of the next state (here it is state B) from the start of state A. So I need a way to find the next state with respect to each state.

user_830293 · Answer

These functions aren't yet part of SPARQL, but SEP-002 for proposed SPARQL 1.2 updates includes more XSD functions, including xsd:dateTime - xsd:dateTime. This is likely implemented in many implementations by now, although possibly with some setup required.

I've implemented it in my Ruby implementation.

SQL Lag() in SPARQL

1 Answers