如何使用更新在嵌套子查询中使用外部查询变量

Question

我正在使用一个更新查询，其中我在嵌套子查询中使用了一个外部变量，但我发现了一个错误：

SQL Error: ORA-00904: "FS"."GR_NUMBER": invalid identifier

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

您的查询存在的问题是您试图访问下一级子查询中的 fs.gr_number 列。您只能访问下一级子查询中的顶级列。

您的声明应该是：

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);

这将相关性降低了一个级别。请注意我还为嵌套子查询设置了别名。

性能应该不会太差，因为 x.gr_number = fs.gr_number 谓词涉及子查询中分析函数正在分区的同一列。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

由于是 Oracle，您可以使用合并子句并使用 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;

如果您仍想使用 roe_number() 函数，下面是查询。加入 table 的 WHERE 子句应该在子查询之外。

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) ;

Answer 3

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);

如何使用更新在嵌套子查询中使用外部查询变量

How to use an outer query variable in a nested sub query using update

sql

oracle

oracle11g

sql-update