Question

当我们在选择列表中使用选择查询时，我们可以使用Order By子句吗？

我想写这样的查询： -

select col1
     , col2
     , (select colX from table2 where table2.col1=table1.col1 and rownum<2 order by colY desc) 
     , (select colXX from table3 where table3.col1=table1.col1 and rownum<2 order by colYY desc)
from table1;

我不能加入这张桌子。它只是我想要的例子。

行。这就是事情。我有以下用SQL Server编写的代码。我想将其转换为Oracle。

SELECT
BANK_ADDRESS1= (SELECT top 1 OWNER_ADDRESS1 
            FROM OWNER_ADDRESS OA, BANK_ACCOUNT
            WHERE PAYMENT.BANK_ACCOUNT_ID = BANK_ACCOUNT.BANK_ACCOUNT_ID
                    and BANK_ACCOUNT.BANK_ID = OA.OWNER_ID
                    order by Isnull (OA.primary_addr , 'N') desc),
PAYEE_ADD1 = (  SELECT top 1 OWNER_ADDRESS1 
                FROM OWNER_ADDRESS OA 
                WHERE OA.OWNER_ID = PAYEE_OWNER.OWNER_ID 
                order by Isnull (OA.primary_addr , 'N') desc ),
FROM    PAYMENT 
            inner JOIN PAYEE ON PAYMENT.PAYMENT_ID = PAYEE.PAYMENT_ID
            inner join OWNER PAYEE_OWNER on PAYEE_OWNER.OWNER_ID = PAYEE.PAYEE_NAME_ID

希望这能清除我真正想要的东西。

Answer 1

你想要这样的东西：

select col1,
       col2,
       (select colX
          from (select col1, colX from table2 order by colY desc) table2
         where table2.col1 = table1.col1
           and rownum < 2),
       (select colXX
          from (select col1, colXX from table3 order by colYY desc) table3
         where table3.col1 = table1.col1
           and rownum < 2)
  from table1;

或者这个：

select col1,
       col2,
       (select max(colX) keep(dense_rank last order by colY)
          from table2
         where table2.col1 = table1.col1),
       (select max(colXX) keep(dense_rank last order by colYY)
          from table2
         where table2.col1 = table1.col1)
  from table1;

此子选择

(select colX from table2 where table2.col1=table1.col1 and rownum<2 order by colY desc)

即使它起作用也不会返回你的预期，因为rownum是在订购之前计算的。您将从满足条件table2.col1 = table1.col1。

的那些中获得随机行

尝试

select (SELECT max(OWNER_ADDRESS1) keep(dense_rank last order by nvl(oa.primary_addr, 'N'))
          FROM OWNER_ADDRESS OA, BANK_ACCOUNT
         WHERE PAYMENT.BANK_ACCOUNT_ID = BANK_ACCOUNT.BANK_ACCOUNT_ID
           and BANK_ACCOUNT.BANK_ID = OA.OWNER_ID) bank_address1,
       (SELECT max(OWNER_ADDRESS1) keep(dense_rank last order by nvl(oa.primary_addr, 'N'))
          FROM OWNER_ADDRESS OA
         WHERE OA.OWNER_ID = PAYEE_OWNER.OWNER_ID) payee_add1
  from PAYMENT
 inner JOIN PAYEE
    ON PAYMENT.PAYMENT_ID = PAYEE.PAYMENT_ID
 inner join OWNER PAYEE_OWNER
    on PAYEE_OWNER.OWNER_ID = PAYEE.PAYEE_NAME_ID

（我本可以做一些语法错误，无法检查）。

在选择列表中的Select语句中排序

1 个答案: