Certes

Hello. I'm an experienced wikignome from enwiki and am still finding my way around Wikidata. I'm currently looking at data quality issues such as children who are older than their parents and property values which are disambiguation pages.

If our areas of interest overlap, if you know of any discussion page for this sort of thing, or if you have ideas for similar types of improvement, please get in touch.

Links

• Wikidata:Database reports/Complex constraints
• Wikidata:Database reports/Complex constraint violations/P106#Link to a Wikimedia disambiguation page

Queries

Child older than parent

SELECT ?child ?childLabel ?cdob ?parent ?parentLabel ?pdob WHERE {
  ?child wdt:P25 ?parent. # Or P22, or P40 reversed
  ?child wdt:P569 ?cdob.
  ?parent wdt:P569 ?pdob.
  FILTER(YEAR(?cdob)<=YEAR(?pdob) && ! REGEX(STR(YEAR(?cdob)), "[05][01]$") && ! REGEX(STR(YEAR(?pdob)), "[05][01]$")).
  SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en". }
}

Try it!