如何在redash中基于计数结果插入查询过滤器

问题描述

我相信这是一个简单的问题，但是由于我对redash不熟悉，所以看起来很难。

我在Redash中有一个查询，

SELECT si.variant_id,v.sku,COUNT(CASE
                 WHEN a.viewable_type = 'Spree::Variant' THEN a.id
             END) AS photo
FROM spree_stock_items si
LEFT JOIN spree_stock_locations sl ON sl.id = si.stock_location_id
LEFT JOIN spree_assets a ON si.variant_id = a.viewable_id
LEFT JOIN spree_variants v ON v.id = si.variant_id
WHERE-- viewable_type = 'Spree::Variant'
sl.name='{{store_location}}'
  AND si.deleted_at IS NULL
  AND sl.country_id = '2'
GROUP BY 1,2
ORDER BY 1
LIMIT 200000

给出如下结果：

到目前为止，我可以在store location上过滤结果。但是现在我想基于列query filter添加photo。我该怎么做？基本上，我想通过store location和photo列中的计数来过滤redash仪表板中的结果。

解决方法

您可以使用having子句-但这需要重复聚合表达式。例如：

SELECT si.variant_id,v.sku,COUNT(a.id) FILTER(WHERE a.viewable_type = 'Spree::Variant') AS photo
FROM spree_stock_items si
LEFT JOIN spree_stock_locations sl ON sl.id = si.stock_location_id
LEFT JOIN spree_assets a ON si.variant_id = a.viewable_id
LEFT JOIN spree_variants v ON v.id = si.variant_id
WHERE-- viewable_type = 'Spree::Variant'
    sl.name='{{store_location}}'
    AND si.deleted_at IS NULL
    AND sl.country_id = '2'
GROUP BY 1,2
HAVING COUNT(a.id) FILTER(WHERE a.viewable_type = 'Spree::Variant') > 1
ORDER BY 1
LIMIT 200000

请注意，我重写了count()以使用标准的filter子句，这使语法更加整洁。

或者，您可以在外部查询中使用子查询和WHERE子句：

SELECT *
FROM (
    SELECT si.variant_id,COUNT(a.id) FILTER(WHERE a.viewable_type = 'Spree::Variant') AS photo
    FROM spree_stock_items si
    LEFT JOIN spree_stock_locations sl ON sl.id = si.stock_location_id
    LEFT JOIN spree_assets a ON si.variant_id = a.viewable_id
    LEFT JOIN spree_variants v ON v.id = si.variant_id
    WHERE-- viewable_type = 'Spree::Variant'
    sl.name='{{store_location}}'
      AND si.deleted_at IS NULL
      AND sl.country_id = '2'
    GROUP BY 1,2
) t
WHERE photo > 1
ORDER BY 1
LIMIT 200000