调用[MySQL]时，定义的case返回“未知列”

我正在为产品的位置创建一个已定义的案例，然后希望稍后将该案例作为值返回。但是，我在“字段列表”中得到错误未知列位置

SELECT location, avg(pcnt), max(pcnt), min(pcnt)
  FROM (
    -- create temporary table 'a' to serve data from inner typing table created below
    SELECT a.date_key, a.num_snowflakes/k.tot_snowflakes AS pcnt
      FROM (
        SELECT 
          date_key,
          CASE
            WHEN location_type_key=2 then 'at_customer' 
            WHEN location_type_key IN (1,13) then 'on_floor' 
            WHEN location_type_key IN (6,7,11) then 'sat1'
            WHEN location_type_key IN (4,5) then 'film'
            WHEN location_type_key IN (8,9) then 'repair'
            WHEN location_type_key IN (12) then 'inspection'
            WHEN location_type_key IN (2) then 'outside' 
            ELSE NULL END AS location,
          COUNT(distinct garment_key) AS num_snowflakes, 
          COUNT(distinct product_key) AS num_skus

          FROM database
          -- excluding vendor return and retired
            WHERE location_type_key NOT IN (3,10)
            -- between 6/15/13 and 8/15/13
              AND date_key >= 20130615 AND date_key <= 20130815
          -- aggregates by day and location case    
          GROUP BY date_key, location
        ) AS a
        JOIN 
        -- create temporary table 'k' to serve 'tot_snowflakes' to table 'a' above
          (SELECT b.date_key, sum(b.num_snowflakes) AS tot_snowflakes 
              FROM (
                SELECT 
                  date_key, 
                  CASE   
                    WHEN location_type_key=2 then 'at_customer' 
                    WHEN location_type_key IN (1,13) then 'on_floor' 
                    WHEN location_type_key IN (6,7,11) then 'sat1'
                    WHEN location_type_key IN (4,5) then 'film'
                    WHEN location_type_key IN (8,9) then 'repair'
                    WHEN location_type_key IN (12) then 'inspection'
                    WHEN location_type_key IN (2) then 'outside' 
                    ELSE NULL END AS location,
                  COUNT(distinct garment_key) AS num_snowflakes, 
                  COUNT(distinct product_key) AS num_skus

                  FROM database
                    WHERE location_type_key NOT IN (3,10)
                    -- between 6/15/13 and 8/15/13
                      AND date_key >= 20130615 AND date_key <= 20130815
                  -- aggregates by day and location case    
                  GROUP BY date_key, location
                ) AS b
            ) AS k
          ON a.date_key=k.date_key
      GROUP BY a.date_key, a.location
    ) AS z

我试图确保我总是调用正确的表，因此我不确定错误来自何处。有人有什么想法吗

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谢谢大家!

最外层的查询从表z中选择

表z由SELECT from表a和JOIN表k派生而来

表a是从SELECT from表数据库派生的

表k是从导出表b中选择导出的

表b是从SELECT from基表数据库派生的

这里的简短回答是，您查询的第一行实际上是询问：

SELECT z.location, avg(z.pcnt), max(z.pcnt), min(z.pcnt)

派生表z只有两列，date_key和pcnt

(SELECT a.date_key, a.num_snowflakes/k.tot_snowflakes AS pcnt
...
) AS z

为了使查询正常工作，表z需要一个位置，该位置必须在每个嵌套选择中都是显式的，直到您可以将其跟踪到要实际读取它的基表为止

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另外，查询似乎做的工作比您试图完成的结果所需的工作要多，但我一直盯着它看，直到我的眼睛失去了聚焦能力，因此，我现在将坚持这个答案：每个需要向上渗透其位置列的派生表都需要显式地选择它

数据库？非常有描述性的名字/讽刺的是，这个查询非常庞大，但我在两个连接的选择的字段中没有看到位置。您应该删除外部选择，以检查联接是否真的有字段位置。谢谢，@t.niese，我会试试。@KarolyHorvath，我取出了真实的数据库名称；