以下语法在Postgresql中运行良好: rev_count.RevName,FROM rev.name as RevName, rat.stars as OrginalRat, count(rat.stars) OVER (PARTITION BY rev.name, m.title) as RevCount
如果一个窗口在同一查询中被多次提供,它是如何计算的?查询解析器是否检查一个窗口是否与另一个窗口相同,或者是否容易地从另一个窗口“派生”。PARTITION BY product_id ORDER BY date ROWS BETWEEN 4 PRECEDING AND CURRENT ROW) three table 数据库引擎如何“优化”这个查询?它是否涉及计算单个窗口并为其他计算更改该