DROP VIEW IF EXISTS Balance;
CREATE VIEW Balance AS
  SELECT Account.ID             AS ID,
      IFNULL(ac.allCredits,0)   AS available,
      IFNULL(hi.credit,0)       AS earned,
      IFNULL(hi.debit,0)        AS spent,
      IFNULL(pr.allPromises, 0) AS promised,
      IFNULL(ca.allArrears, 0)  AS arrears,
      even.until                AS even_until
  FROM Account
     LEFT OUTER JOIN (
         SELECT debtor, sum(difference) AS allArrears
         FROM CurrentArrears
         GROUP BY debtor
     )                          AS ca ON Account.ID=ca.debtor
     LEFT OUTER JOIN (
         SELECT account, sum(difference) AS allCredits
         FROM AvailableCredits
         GROUP BY account
     )                          AS ac ON Account.ID=ac.account
     LEFT OUTER JOIN (
         SELECT a.ID AS ID, sum(difference) AS allPromises
         FROM CurrentArrears ca
             JOIN Credit c ON ca.targetCredit = c.credId
             JOIN Account a ON a.ID = c.account
         GROUP BY a.ID
     )                          AS pr ON Account.ID=pr.ID
     LEFT OUTER JOIN (
         SELECT account,
                sum(credit) AS credit,
                sum(debit) AS debit
         FROM History
         GROUP BY account
     )                          AS hi ON Account.ID=hi.account
     LEFT OUTER JOIN (
         SELECT d.debtor     AS account,
                max(d.date)  AS until
         FROM Debit d
             LEFT OUTER JOIN CurrentArrears ca ON d.debtor = ca.debtor
         GROUP BY d.debtor, ca.debtor
         HAVING COUNT(
             -- Restricts the counting to the settled debts:
             CASE d.value WHEN d.paid THEN 1 ELSE NULL END
           ) -- Considers that there might be no current arrears:
           AND d.date <= IFNULL( min(ca.date), '9999-99-99' )
     )                          AS even ON Account.ID=even.account
  ;