use enwiki_p;

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#select * from page_props limit 10;

select count(*) from (select pp_value from page_props WHERE pp_value LIKE 'Q%' and pp_propname = 'wikibase_item') as inner_query;

select count(*) from (select distinct pp_value from page_props WHERE pp_value LIKE 'Q%' and pp_propname = 'wikibase_item') as inner_queries2;

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select count(distinct pp_value) from (select pp_value from page_props WHERE pp_value LIKE 'Q%' and pp_propname = 'wikibase_item') as inner_query;

select count(distinct pp_value) from (select pp_value from page_props WHERE pp_value LIKE 'Q%' and pp_propname = 'wikibase_item') as inner_queries2;