如何在左连接中使用多个子查询来检索连接数据点

Question

您好，我的代码存在一些问题，我不确定缺少关键字是什么意思。

SELECT  a.equipment_id, a.equipment_description, a.failure_class,
        b.equipment_display_mapping_id,
        c.equipment_display_category_name,
        d.link_id, d.location_id,
        e.rd_attr_txt, e.node_fr_id_num, e.node_to_id_num,
        f.node_to_id_num as Previous_node
FROM Equipment_Detail a
LEFT JOIN equipment_display_mapping b on b.equipment_id = a.equipment_id
LEFT JOIN equipment_display_category c on c.equipment_display_category_id =  b.equipment_display_category_id
LEFT JOIN equipment_location_mapping d on d.equipment_id = a.equipment_id
LEFT JOIN vw_gis_link e on e.lk_id_num = d.link_id
LEFT JOIN 
    (
        SELECT node_to_id_num 
        FROM vw_bis_link_details
        WHERE node_to_id_num = e.node_fr_id_num
    ) as f on d.link_id = f.link_id
WHERE 1=1 and a.equipment_type_id = 113;

出现以下错误：

ORA-00905: 缺少关键字
00905. 00000 - “缺少关键字”
*原因：

*行动：
行错误：17 列：7

Answer 1

您在这里使用 link_id 加入，但您只 select node_to_id_num。同样在 Oracle 中，如果我没记错的话，在对表进行别名时不能使用 AS。所以用 f

代替 as f

(
    SELECT node_to_id_num 
    FROM vw_bis_link_details
    WHERE node_to_id_num = e.node_fr_id_num
) f on d.link_id = f.link_id

如何在左连接中使用多个子查询来检索连接数据点

How do use multiple subquery within left joins to retrieve connecting data points

sql

subquery

left-join