The best replacement for subquery is join.

The best alternatives to subquery are rated as following:
★★★★★  join
★★★  temp table
★★★  cte
★★★  inner join
★★  join performance
★★  correlated subquery
★★  join oracle
★  left join
★  derived table
★  nested query
★  join sql server
★  join which is faster
★  inline view
★  outer join
  join mysql
  inline query
  left outer join
  join why
  join mysql performance
  derived tables
  self join
  join sql
  join which is better

Your alternative for subquery is not listed? Suggest!
Speaking about subquery, one probably shouldn't forget about exists.

Other search terms related to subquery and their ratings are:

★★★★★ exists
★★★★ group by
★★ multiple rows
★★ join
in clause
aggregate function
having clause
case statement
group by in sql server
left join
You have in mind a companion for subquery and it is not yet here? Propose!

Google Trends

Scale is based on the average worldwide traffic of subquery in all years. Click on graph for more.
temp table