Question

我不确定如何在不引起混淆的情况下提出此问题，但让我尝试用我的代码的简化版本进行演示（因为我的代码太长了，很可能会在这一点上使问题感到困惑）。

我有一个WITH语句，该语句定义了多个CTE，在最后一个CTE中，我有一个CASE语句，该语句采用了早期CTE的值，但是由于某种原因，它引发了错误：

The multi-part identifier "RESULT1.total_revenue" could not be bound.

我的代码大致如下（简化）：

; with RESULT1 as (
        some code here which returns the columns: client_id, employee_name, total_revenue
        ),
    RESULT2 as (
        some code here which uses the client_id and employee_name from RESULT1 to get employee_team_names from another table employee_teams via a join
        ),
    RESULT3 as (
        some code here which then uses RESULT2 to then get the client_names from another table for each of the client_id found above
        ),
    RESULT4 as (
        now the problem here. I want to then take the client_names found above and do a join in another table to find clean_client_names
        however, if RESULT1.total_revenue is 0, then we can just put 'Not Needed' into the clean_client_name field
        my attempted code below which is throwing the error shown above

        select RESULT3.*,
                    (case when RESULT1.total_revenue = 0 then 'Not Needed' else clean_names_lookup_table.clean_client_name end) as clean_client_name
            from RESULT3
            left join clean_names_lookup_table
            on RESULT3.client_name = clean_names_lookup_table.client_name
        )

Answer 1

这是您的CTE：

 select RESULT3.*,
                (case when RESULT1.total_revenue = 0 then 'Not Needed' else clean_names_lookup_table.clean_client_name end) as clean_client_name
 from RESULT3 left join
      clean_names_lookup_table
      on RESULT3.client_name = clean_names_lookup_table.client_name

引用RESULT1尚未定义。您只能引用FROM子句中定义的表别名。 FROM子句中没有这个名称。

您有两种选择：

JOIN中的RESULT1，因此引用有效。
将您想要的列添加到RESULT2和RESULT3中，以便将其作为RESULT3的一部分。

Answer 2

您需要在JOIN查询中RESULT1表RESULT4，否则RESULT1是未知的。大概RESULT3也有一个名为client_id的字段，在这种情况下，您将编写：

    select RESULT3.*,
                (case when RESULT1.total_revenue = 0 then 'Not Needed' else clean_names_lookup_table.clean_client_name end) as clean_client_name
        from RESULT3
        join RESULT1 on RESULT1.client_id = RESULT3.client_id
        left join clean_names_lookup_table
        on RESULT3.client_name = clean_names_lookup_table.client_name

SELECT嵌套在WITH语句中

2 个答案: