[GitHub] [jena] rubensworks commented on issue #1615: LATERAL join

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rubensworks commented on issue #1615:
URL: https://github.com/apache/jena/issues/1615#issuecomment-1313491885

   So if I understand correctly, `LATERAL` is like an (inner) join, but where top-down execution (LHS->RHS) is enforced, as opposed to the default bottom-up evaluation when working with sub-queries.
   
   > In PostgreSQL, LATERAL seems to be a modifier to one of the join operations. To some, people, it's not then a join operator but a web search finds "lateral join" [such usage](https://docs.snowflake.com/en/sql-reference/constructs/join-lateral.html). It is still a "combining operator".
   
   > In that style, there could be OPTIONAL LATERAL, c.f. LEFT JOIN LATERAL, or reversed which IMO reads better in SPARQL, but wouldn't here still be LATERAL {... because in SPARQL INNER JOIN is the empty string :-).
   
   Applying this approach on different logical join types definitely makes sense to me. So considering `LATERAL` a join modifier seems useful.


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