oracle - SQL performance for select from where result of table -

i ask performance of sql. query:

select      a.code    ,a.name    ,(select         b.price      b      b.card = a.card      , b.quote = a.quote)    ,(select         b.quantity      b      b.card = a.card      , b.quote = a.quote) a.flag = '0'   , a.date = '2016/09/02' 

something this. performance query? slow if data big amount. how should make query more performance?

sorry poor english , in advance

try this, faster in time execute

select      a.code    ,a.name    ,b.price    ,b.quantity  left join b on b.card = a.card , b.quote = a.quote a.flag = '0' , a.date = '2016/09/02