migration with common table expressions

invoice_project

WITH 
  migrated_invoices AS (
           UPDATE invoices
           SET invoice_type='cutting_edge',
           WHERE invoice_type='oldie'
           RETURNING id, status, amount, project_id
    ),
  invoice_amounts_by_status AS (SELECT
      project_id AS invoice_project_id,
      sum((CASE WHEN (migrated_invoices.status = 'paid')
             THEN (migrated_invoices.amount)
           ELSE 0
           END)
      ) AS invoice_amount_paid,
      sum((CASE
           WHEN (migrated_invoices.status = 'pending'))
             THEN (migrated_invoices.amount)
          ELSE 0
          END)
      ) AS invoice_amount_projected,
      array_agg(migrated_invoices.id) AS additional_invoice_ids
      FROM migrated_invoices
      GROUP BY project_id)
    UPDATE projects
    SET
      invoice_ids = array_cat(projects.invoice_ids, additional_invoice_ids),
      total_paid = total_paid + invoice_amount_paid,
      total_projected = total_projected + invoice_amount_projected,
    FROM migrated_invoices, invoice_amounts_by_status
    WHERE projects.id = migrated_invoices.project_id AND
          projects.id = invoice_project_id