присоединиться к просмотру таблицы

Question

Я хочу преобразовать левое соединение в view table.

Following is my SQL

 SELECT d.account_no, COALESCE(d.deposits, 0) - COALESCE(w.withdrawals, 0) 
   AS balance
  FROM (SELECT account_no, SUM(deposit_amount) AS deposits
   FROM deposits
  GROUP BY account_no) d
  LEFT JOIN (SELECT account_no, SUM(withdraw_amount) AS withdrawals
       FROM withdraws
       GROUP BY account_no) w ON w.account_no = d.account_no

Я хочу создать view таблицу.

Как я могу это сделать? Кто-нибудь может помочь?

Answer 1

Создать вид (один раз) и использовать в левом соединении

CREATE  VIEW my_view AS 
SELECT account_no, SUM(withdraw_amount) AS withdrawals
       FROM withdraws
       GROUP BY account_no
;


SELECT d.account_no, COALESCE(d.deposits, 0) - COALESCE(w.withdrawals, 0) 
 AS balance
FROM (SELECT account_no, SUM(deposit_amount) AS deposits
 FROM deposits
GROUP BY account_no) d
LEFT JOIN my_view  w ON w.account_no = d.account_no