How to reduce x select to 1 select?-CodePudding

I have the following 3 selects and I want to improve performance, what can I do?

select object into lastUpdate 
from data
where predicate = '#lastUpdate' 
and subject = 'subject1';
select object into latitude
from data
where predicate = '#latitude'
and subject = 'subject1';
select object into longitude
from data
where predicate = '#longitude'
and subject = 'subject1';

Thank you

CodePudding user response：

You can use a JOIN:

select lu.object, lat.object, lon.object
  into lastupdate, latitude, longitude
from data lu
  left join data lat on lat.subject = lu.subject and lat.predicate = '#latitude' 
  left join data lon on lon.subject = lu.subject and lon.predicate = '#longitude' 
where lu.subject = 'subject1'
  and lu.predicate = '#lastUpdate';