[Wikidata-bugs] [Maniphest] [Commented On] T172113: ConcurrentModificationException on non-grouping query with aggregates in SELECT

[WikidataFacts]

WikidataFacts added a comment.

Note that this can also occur on grouping queries:

SELECT ?x (COUNT(*) AS ?total) (SUM(?y) AS ?ys) (?ys/?total AS ?ratio) WHERE {
  ?x wdt:P31 wd:Q1.
  BIND(1 AS ?y)
}
GROUP BY ?x

And an alternative workaround is to inline the variables into the SELECT, i. e. (SUM(?y)/COUNT(*) AS ?ratio). The advantage of this is that you can still use ?ratio in a HAVING clause on the grouping query (a FILTER in the outer query is less efficient).

TASK DETAIL

https://phabricator.wikimedia.org/T172113

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To: WikidataFacts
Cc: WikidataFacts, Esc3300, Aklapper, Smalyshev, Lucas_Werkmeister_WMDE, PokestarFan, GoranSMilovanovic, QZanden, EBjune, merbst, Avner, debt, Gehel, Jonas, FloNight, Xmlizer, Izno, jkroll, Wikidata-bugs, Jdouglas, aude, Tobias1984, Manybubbles, Mbch331, Krenair

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