DBSCAN(Density-Based Spatial Clustering of Applications with Noise)是一种基于密度的经典聚类算法,由 Martin Ester 等人于 1996 年提出。该算法通过定义两个关键参数(邻域半径 eps 和最小样本数 minPts)来识别高密…
-- 示例:多步骤计算用户留存率
WITH
first_purchases AS (SELECT customer_id,MIN(purchase_date) AS first_purchase_dateFROM purchasesGROUP BY customer_id
)
,
monthly_active_users AS (SELECT DATE_FORMAT(purchase_date, %Y-%m-01) AS month ,COUNT(DISTIN…
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接之前 blog 【OS】【Nuttx】【构建】cm…