Question

我正在使用更新查询，其中在嵌套子查询中使用外部变量，但是发现错误：

SQL错误：ORA-00904：“ FS”。“ GR_NUMBER”：无效的标识符

update table fs set fs.branch_id=
(select branch_id
from
    (select  branch_id,row_number() over(PARTITION by gr_number order by updated_ts desc) as Sno
from admission_log
where gr_number=fs.gr_number )
where sno=1) ;

Answer 1

查询的问题在于，您正在尝试访问下两级的子查询中的fs.gr_number列。您只能访问下一级的子查询中的顶级列。

您的声明应为：

UPDATE fs
SET    fs.branch_id = (SELECT branch_id
                       FROM   (SELECT branch_id,
                                      gr_number,
                                      row_number() OVER (PARTITION BY gr_number ORDER BY updated_ts DESC) AS sno
                               FROM   admission_log) x
                       WHERE  x.gr_number = fs.gr_number
                       AND    sno = 1);

将相关性向下移动一级。请注意，我还如何为嵌套的子查询加上别名。

性能不应该太差，因为x.gr_number = fs.gr_number谓词涉及子查询中分析功能所在的同一列。这应该允许Oracle适当地过滤子查询。

ETA：您也可以改用MERGE语句：

MERGE INTO fs tgt
  USING (SELECT branch_id,
                row_number() OVER (PARTITION BY gr_number ORDER BY updated_ts DESC) AS sno
         FROM   admission_log) src
    ON (tgt.gr_number = src.gr_number AND src.sno = 1)
WHEN MATCHED THEN
  UPDATE tgt.branch_id = src.branch_id;

Answer 2

使用此代码：

update fs a
set a.branch_id =
   (select c.branch_id
      from (select b.branch_id,
                   row_number() over(PARTITION by b.gr_number order by b.updated_ts desc) as Sno
              from admission_log b
             where b.gr_number = a.gr_number) c
     where c.sno = 1);

Answer 3

由于它是Oracle，因此可以使用merge子句并使用min（）函数而不是row_number（）函数来获取值。

merge into table fs using
(select gr_number, min(branch_id) as branch_id from admission_log) qry
on
(fx.gr_number = qry.gr_number)
when matched then
update
set
fs.branch_id = qry.branch_id;

如果您仍然想使用roe_number（）函数，则查询如下。您要加入表格的WHERE子句应在子查询之外。

update table fs set fs.branch_id=
(select branch_id
from
(select  branch_id,row_number() over(PARTITION by gr_number order by updated_ts desc)
as Sno
from admission_log)
where sno=1
and gr_number=fs.gr_number) ;

如何使用更新在嵌套子查询中使用外部查询变量

3 个答案: