Question

select
  whatever
from
  bank_accs b1,
  bank_accs b2,
  table3 t3
where
  t3.bank_acc_id = t1.bank_acc_id and
  b2.bank_acc_number = b1.bank_acc_number and
  b2.currency_code(+) = t3.buy_currency and
  trunc(sysdate) between nvl(b2.start_date, trunc(sysdate)) and nvl(b2.end_date, trunc(sysdate));

我的问题是b2上的日期（现状）检查。现在，我需要为每个t3xb1返回一行（当然，t3 = ~10个表加入），即使b2中只有无效记录（日期）。如何正确地外接这个位？不能使用ANSI连接，必须在单个平面查询中执行。感谢。

Answer 1

如果我理解你，只需将外符号（+）添加到b2的所有列：

select
  whatever
from
  bank_accs b1,
  bank_accs b2,
  table3 t3
where
  t3.bank_acc_id = t1.bank_acc_id and
  b2.bank_acc_number = b1.bank_acc_number and
  b2.currency_code(+) = t3.buy_currency and
  trunc(sysdate) between nvl(b2.start_date(+), trunc(sysdate)) and nvl(b2.end_date(+), trunc(sysdate));

Answer 2

可以使用不等式编写旧式外连接，但它容易出错。我建议你使用内联视图，外连接将清晰明确：

SELECT whatever
  FROM bank_accs b1,
       table3 t3,
       (SELECT b2.*
          FROM bank_accs b2
         WHERE trunc(sysdate) BETWEEN nvl(b2.start_date, trunc(sysdate)) 
                                  AND nvl(b2.end_date, trunc(sysdate))
       ) b2
 WHERE t3.bank_acc_id = t1.bank_acc_id
   AND b2.bank_acc_number = b1.bank_acc_number
   AND b2.currency_code(+) = t3.buy_currency;

Oracle SQL外连接查询难题

2 个答案: