以子查询作为数据源的 SQL 更新不起作用 (Postgresql)

Question

我有以下 SQL DML 更新命令，但语法不正确且命令不起作用:

UPDATE hmsg_vehicle_category
SET hmsg_vehicle_category.hmsg_id, hmsg_vehicle_category.vehiclecategories_inputname
SELECT l_p.hmsg_id, tmp_p_vc.inputname 
FROM hmsg_him_product AS l_p INNER JOIN (  SELECT p.id, vc.inputname
                                           FROM him_product p INNER JOIN vehicle_category vc
                                              ON p.id = vc.product
                                           ORDER BY p.id, vc.inputname DESC ) AS tmp_p_vc
    ON l_p.products_id = tmp_p_vc.id
WHERE l_p.hmsg_id = 171;

我如何执行这个 SQL 命令？ snytax哪里出错了？

感谢您的帮助!

问候 玛维夫

Answer 1

类似于:

update hmsg_vehicle_category set
    hmsg_id = l_p.hmsg_id,
    vehiclecategories_inputname = tmp_p_vc.inputname 
from hmsg_him_product as l_p
    inner join him_product as p on p.id = l_p.products_id 
    inner join vehicle_category as vc on vc.product = p.id
where l_p.hmsg_id = 171

请注意，这将更新 hmsg_vehicle_category 表中的所有记录。可能您想将其添加到 where 子句中:

update hmsg_vehicle_category as hvc set
    vehiclecategories_inputname = tmp_p_vc.inputname 
from hmsg_him_product as l_p
    inner join him_product as p on p.id = l_p.products_id 
    inner join vehicle_category as vc on vc.product = p.id
where
    l_p.hmsg_id = 171 and hvc.hmsg_id = 171

但我目前无法提供更具体的建议，因为您的问题还不清楚。