Question

我尝试了以下SQL查询，并且出现以下错误：

Select TOP 1 CITY,MAX(LEN(CITY)) 
from STATION 
ORDER BY CITY ASC

错误

选择列表中的“ STATION.CITY”列无效，因为该列未包含在聚合函数或GROUP BY子句中。

表：

CREATE TABLE City (
  ID Integer NOT NULL,
  PRIMARY KEY (ID),
  Name VARCHAR (255),
  CountryCode VARCHAR (255),
  District VARCHAR (255),
  PopulationofCity Integer
);

Answer 1

您必须分组分组城市

 Select TOP 1 CITY,MAX(LEN(CITY)) 
 from STATION group by CITY
 ORDER BY CITY ASC

Answer 2

您缺少分组依据

Select TOP 1 CITY,MAX(LEN(CITY)) from STATION 
group by city
ORDER BY CITY ASC

Answer 3

您可能正在寻找最长的城市名称。

然后按降序排列

SELECT TOP 1 CITY, LEN(CITY)
FROM STATION
GROUP BY CITY
ORDER BY LEN(CITY) DESC

Answer 4

有帮助吗？

<p-dropdown [options]="cars" [(ngModel)]="selectedCar2" filter="true">
    <ng-template let-item pTemplate="selectedItem">
        <img src="assets/showcase/images/demo/car/{{item.label}}.png" style="width:16px;vertical-align:middle" />
        <span style="vertical-align:middle; margin-left: .5em">{{item.label}}</span>
    </ng-template>
</p-dropdown>

选择列表中的“ City.Name”列无效，因为它未包含在聚合函数或GROUP BY子句中

4 个答案: