sql中带有无效标识符错误的子查询答案

【问题标题】：Subquery with invalid identifier error in sqlsql中带有无效标识符错误的子查询
【发布时间】：2013-05-29 22:56:04
【问题描述】：

要提前选择旅游日期和站点名称，总费用超过 230 且该旅游超过 7 人。完整的代码如下，联合工作的第一部分。

SELECT tour_date AS "Departure Date",  site_name "Site Name"
FROM partres, reservation, tour, site
WHERE partres.res_id = reservation.res_id
  AND reservation.tour_id = tour.tour_id
  AND tour.site_id = site.site_id
GROUP BY tour_date, site_name
HAVING COUNT(part_id) > 7

  UNION

SELECT tour_date AS "Departure Date",  site_name "Site Name"
FROM (
  SELECT res_id,tour_date,site_name, (res_partcost +NVL(RES_GEARCOST,0)) as "total_cost" 
  FROM reservation,site,tour) 
WHERE  reservation.tour_id = tour.tour_id
  AND tour.site_id = site.site_id
  AND total_cost > 230
GROUP BY tour_date, site_name;

我仍然遇到错误

ORA-00904: "TOTAL_COST": invalid identifier
00904. 00000 -  "%s: invalid identifier"
*Cause:    
*Action:
Error at Line: 437 Column: 7

谢谢

【问题讨论】：

认为您忘记将 total_cost 放入第一个 SELECT 语句
你想完成什么？内部查询没有 where 子句，因此您没有按任何条件加入表。字段 reservation.*、tour.* 和 site.* 在您的内部查询之外不可用。
想提前选择旅游日期和地点名称，总费用超过230，而且旅游人数超过7人。

标签： sql oracle subquery

【解决方案1】：

您需要在子查询中移动连接条件

SELECT tour_date AS "Departure Date",  site_name "Site Name"
FROM (
    SELECT res_id,tour_date,site_name, (res_partcost +NVL(RES_GEARCOST,0)) as "total_cost" 
    FROM reservation,site,tour
    WHERE reservation.tour_id = tour.tour_id
    AND tour.site_id = site.site_id ) Res1
WHERE Res1.total_cost > 230 // this will not be displayed in a result
GROUP BY tour_date, site_name;

【讨论】：

【解决方案2】：

union 不会在条件之间给出“和”。它会给你一个“或”（因为任何符合任一条件的都将被包括在内）。

我认为您应该将其表述为带有子查询的单个查询。此外，正确的连接语法也是一个好处：

SELECT tour_date AS "Departure Date",  site_name "Site Name"
FROM partres p join
     reservation r
     on p.res_id = r.res_id join
     tour t
     on r.tour_id = t.tour_id and
        (res_partcost + coalesce(RES_GEARCOST,0)) > 230 join
     site s
     on t.site_id = s.site_id
GROUP BY tour_date, site_name
having COUNT(part_id) > 7;

此版本猜测total_cost 在reservation 表中。

【讨论】：