从 Oracle 数据库迁移到 Postgesql 分层查询

Question

我正在将 Oracle 数据库迁移到 PosgreSQL。我有这样一个分层查询，如下所示。我成功地做了更简单的分层查询。但我不能做这个查询。有人可以帮忙查询 PostgreSQL 吗？

Oracle查询：

select count(*) cnt
from   list nl,
       parts spl
where  nl.month     = Month_
and    nl.year      = Year_
and    nl.date_del  is null
and    nl.id(+)     = spl.id
and    nl.dep_owner = dep_owner_
and    nl.dep_id in ( select d.dep_id
                      from departments d
                      connect bt prior d.dep_id = d.parent_id
                      start with d.dep_id = dep_id_)
connect by prior spl.id = spl.parent_id
start with spl.index = trim(part_index_)

Postgres查询：

 WITH RECURSIVE cteroot AS (SELECT count(*) AS cnt
                       FROM parts spl
                       LEFT JOIN list nl ON spl."ID" = nl."ID"
                       where nl."MONTH"= Month_
                       and nl."YEAR" = Year_
                       and nl."DATE_DEL" is null
                       and nl."DEP_OWNER" = dep_owner_
                       and nl."DEP_ID" IN (WITH RECURSIVE cte AS (SELECT "DEP_ID"
                                           FROM departments
                                           where "DEP_ID"= dep_id_
                                           UNION
                                           SELECT d."DEP_ID"
                                           FROM departments d
                                           JOIN cte ON d."PARENT_ID"= cte."DEP_ID")
                                           SELECT "DEP_ID"
                                           FROM cte
                                           )
                       and spl."INDEX" = TRIM(part_index_)
                       UNION
                       SELECT count(*) AS cntd
                       FROM parts spld
                       LEFT JOIN list nld ON spl."ID" = nld."ID"
                       where nld."MONTH"= Month_
                       and nld."YEAR" = Year_
                       and nld."DATE_DEL" is null
                       and nld."DEP_OWNER" = dep_owner_
                       and nld."DEP_ID" IN (WITH RECURSIVE cted AS (SELECT "DEP_ID"
                                                                    FROM departments dt
                                                   where dt."DEP_ID"= dep_id_
                                                   UNION
                                                   SELECT td."DEP_ID"
                                                   FROM departments td
                                                   JOIN cted ON td."PARENT_ID"= cted."DEP_ID")
                                             SELECT "DEP_ID"
                                             FROM cted
                                             )
 SELECT count(*) cntv
 FROM cteroot)`

此代码有效但不正确

Answer 1

您没有在 Oracle 查询中使用

LEFT OUTER JOIN

。是的，您可以在联接中使用

(+)

，但在

START WITH

和

CONNECT BY

子句中，您需要

spl.index

和

spl.id

等于另一个值，并且当

OUTER JOIN

发生并且vlues 将是

NULL

所以连接只能是

INNER JOIN

.

因此，您的 Oracle 查询实际上是：

SELECT COUNT(*) cnt
FROM   list l
       INNER JOIN parts p
       ON ( l.id = p.id )
WHERE  l.month     = Month_
AND    l.year      = Year_
AND    l.date_del  IS NULL
AND    l.dep_owner = dep_owner_
AND    l.dep_id IN ( SELECT d.dep_id
                     FROM   departments d
                     CONNECT BY PRIOR d.dep_id = d.parent_id
                     START WITH d.dep_id = dep_id_ )
CONNECT BY PRIOR p.id = p.parent_id
START WITH p.index = trim(part_index_)

至少，您需要将

LEFT JOIN

s更改为

INNER JOIN

s。