gaha

    SELECT COUNT(*)        as "count",
         COALESCE(MAX(EXTRACT(EPOCH FROM age(now(), runs.created_at)))::bigint, 0) AS "max_age"
    FROM runs
      JOIN stacks ON runs.stack_id = stacks.id
      JOIN worker_pools ON worker_pools.id = stacks.worker_pool_id
      JOIN accounts ON stacks.account_id = accounts.id
      /*unnesting*/
      join (SELECT accounts_other.id,  COUNT(*) as cnt
       FROM accounts accounts_other
         JOIN stacks stacks_other ON accounts_other.id = stacks_other.account_id
         JOIN runs runs_other ON stacks_other.id = runs_other.stack_id
       WHERE accounts_other.id
         AND (stacks_other.worker_pool_id IS NULL OR
          stacks_other.worker_pool_id = worker_pools.id)
         AND runs_other.worker_id IS NOT NULL
        group by accounts_other.id) as acc_cnt 
      on acc_cnt.id = accounts.id and  accounts.max_public_parallelism / 2 > acc_cnt.cnt
     /*end*/
    WHERE worker_pools.is_public = true
      AND runs.type IN (1, 4)
      AND runs.state = 1
      AND runs.worker_id IS NULL
      /* maybe also copy these filter predicates inside the unnested query above */