我有这个我要优化的大型查询,我已经对它进行了优化,但有时仍然很慢(> 1s):
select count(DISTINCT if(ps15.specification in ('All Season'),p.products_id,NULL)) as count1 ,count(DISTINCT if(ps15.specification in ('Winter'),p.products_id,NULL)) as count2 ,count(DISTINCT if(ps15.specification in ('Zomer'),p.products_id,NULL)) as count3 ,count(DISTINCT if(ps15.specification in ('Winter 2012'),p.products_id,NULL)) as count4 ,count(DISTINCT if(ps15.specification in ('Zomer 2013'),p.products_id,NULL)) as count5 ,count(DISTINCT if(ps15.specification in ('Winter 2013'),p.products_id,NULL)) as count6 ,count(DISTINCT if(ps15.specification in ('Zomer 2014'),p.products_id,NULL)) as count7
from (products p)
inner join (products_to_categories p2c)
on (p.products_id = p2c.products_id)
inner join (products_attributes pa)
on (p.products_id = pa.products_id)
inner join (products_options_values pv)
on (pa.options_values_id = pv.products_options_values_id)
inner join (products_stock …