SQL Server:分组时聚合错误 [英] SQL Server: aggregate error on grouping

问题描述

我有一个称为任务的表，该表列出了工作人员可以完成的不同任务.然后，我有一个关系表，该表将已完成的任务链接到工作人员.我正在尝试编写查询，该查询根据工作人员ID将任务分组到一个列表中，但是查询给了我以下错误(请参阅下文).

I have a table called tasks, which lists different tasks a worker can complete. Then i have a relationship table that links a completed task to a worker. I'm trying to write query that groups the tasks into a list based on the worker id, but the query gives me the following error (see below).

Column 'mater.dbo.worker_task_completion.FK_task_id' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause.

表格

CREATE TABLE [dbo].[tasks]
(
    [task_id] [int] IDENTITY(1,1) NOT NULL,
    [name] [nvarchar](50) NOT NULL,
    [icon] [nvarchar](max) NULL,
    [isActive] [int] NOT NULL,
    [time] [int] NOT NULL,
    CONSTRAINT [PK_tasks] PRIMARY KEY CLUSTERED 
(
    [task_id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]



CREATE TABLE [dbo].[worker_task_completion]
(
    [FK_worker_id] [int] NOT NULL,
    [FK_task_id] [int] NOT NULL,
    [update_date] [datetime] NOT NULL,
    CONSTRAINT [PK_worker_task_completion] PRIMARY KEY CLUSTERED 
(
    [FK_worker_id] ASC,
    [FK_task_id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]

查询

SELECT top 100 wtc.FK_worker_id, 
                tasks = Stuff((SELECT ', ' + dbo.tasks.NAME 
                                FROM   dbo.tasks
                               WHERE  dbo.tasks.task_id = 
                                     wtc.FK_task_id
                               FOR xml path ('')), 1, 1, '')
        FROM   dbo.worker_task_completion AS wtc 
                LEFT JOIN dbo.tasks AS tc 
                       ON tc.task_id = wtc.fk_task_id
        -- WHERE  wtc.FK_worker_id IN ()
GROUP  BY wtc.FK_worker_id

推荐答案

嗯.您不能将非聚合列用于相关性子句.解决方案是将 JOIN 移到子查询中:

Hmmm. You cannot use a non-aggregated column for the correlation clause. The solution is to move the JOIN into the subquery:

SELECT top 100 wtc.FK_worker_id, 
       stuff((SELECT ', ' + t.NAME 
              FROM dbo.worker_task_completion wtc2 JOIN
                   dbo.tasks t
                   ON t.task_id = wtc2.FK_task_id
              WHERE wtc2.FK_worker_id = wtc.FK_worker_id
              FOR xml path ('')
             ), 1, 2, ''
            ) as tasks
FROM (SELECT DISTINCT wtc.FK_worker_id
      FROM dbo.worker_task_completion wtc 
     ) wtc
        -- WHERE  wtc.FK_worker_id IN ()

请注意，我更改了 STUFF()的第二个参数.大概是要删除空格和逗号.

Note that I changed the second argument for STUFF(). Presumably, you want to remove the space as well as the comma.

这篇关于SQL Server:分组时聚合错误的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！