PostgreSQL

Question

我正在尝试进行同期群分析，并根据租户的第一个租赁年（= 租户第一次租用的年份）比较平均租金数。基本上，我在问一个问题：与第一年为 2015 年的租房者相比，我们是否保留了第一年租房为 2013 年的租房者？

这是我的代码：

SELECT renter_id, 
       Min(Date_part('year', created_at)) AS first_rental_year, 
       ( Count(trip_finish) )             AS number_of_trips 
FROM   bookings 
WHERE  state IN ( 'approved', 'aboard', 'ashore', 'concluded', 'disputed' ) 
  AND  first_rental_year = 2013 
GROUP  BY 1 
ORDER  BY 1;

我收到的错误信息是：

ERROR:  column "first_rental_year" does not exist
LINE 6: ... 'aboard', 'ashore', 'concluded', 'disputed') AND first_rent...
                                                             ^

********** Error **********

ERROR: column "first_rental_year" does not exist
SQL state: 42703
Character: 208

非常感谢任何帮助。

Answer 1

SELECT renter_id,
       Count(trip_finish) AS number_of_trips 
FROM (
        SELECT renter_id, 
               trip_finish,
               Min(Date_part('year', created_at)) AS first_rental_year
        FROM   bookings 
        WHERE  state IN ( 'approved', 'aboard', 'ashore', 'concluded', 'disputed' ) 
     ) T
WHERE first_rental_year = 2013  
GROUP  BY renter_id
ORDER  BY renter_id ;

Answer 2

错误：

SQL Error [42703]: ERROR: column XYZ does not exist

检查列字段周围是否有 双引号：

不好：

update public."AppTime" t Set "CustomTask"= 'XYZ' where  t.SharedAppId = 12890;

好：

用双引号将“SharedAppId”括起来

update public."AppTime" t Set "CustomTask"= 'XYZ' where  t."SharedAppId" = 12890;

If you created the table without quotes, you should not use quotes when querying it, and vice versa. This is explained in the manual: "If you want to write portable applications you are advised to always quote a particular name or never quote it"

PostgreSQL - ERROR: column does not exist SQL state: 42703

PostgreSQL - ERROR: column does not exist SQL state: 42703

sql

column-alias