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当前在 BigQuery 中？

[英]CURRENT in BigQuery?

原文 2022-08-11 23:15:38 0 1 sql/ google-cloud-platform/ google-bigquery

I've noticed that CURRENT is a reserved keyword for BigQuery at: https://cloud.google.com/bigquery/docs/reference/standard-sql/lexical .我注意到CURRENT是 BigQuery 的保留关键字： https://cloud.google.com/bigquery/docs/reference/standard-sql/lexical 。

What exactly does CURRENT do? CURRENT到底是做什么的？ I've only seen it as a prefix for things such as CURRENT_TIME() , CURRENT_DATE() , and other such stuff but have never seen it by itself.我只将它视为CURRENT_TIME() 、 CURRENT_DATE()和其他此类东西的前缀，但从未单独见过它。 Is this just reserved for future usage or do any SQL statements contain that as a keyword?这只是为将来使用而保留，还是任何 SQL 语句都包含它作为关键字？

1 个解决方案

Just to add on the comment of @Jaytiger:只是添加@Jaytiger的评论：

CURRENT keyword seems to be reserved as a part of SQL 2016 spec. CURRENT关键字似乎保留为 SQL 2016 规范的一部分。 en.wikipedia.org/wiki/SQL_reserved_words And you can check it's usage in another DBMS implementations like Oracle, SQL Server. en.wikipedia.org/wiki/SQL_reserved_words 您可以检查它在其他 DBMS 实现中的使用情况，例如 Oracle、SQL 服务器。 hope this is helpful.希望这会有所帮助。 stackoverflow.com/questions/49110728/where-current-of-in-pl-sql stackoverflow.com/questions/49110728/where-current-of-in-pl-sql

In BigQuery CURRENT clause is used on defining frame_start and frame_end in window functions .在 BigQuery 中， CURRENT子句用于在window 函数中定义frame_start 和 frame_end 。

A window function, also known as an analytic function, computes values over a group of rows and returns a single result for each row. window function，也称为分析 function，计算一组行的值并为每行返回一个结果。

A common usage for this is calculating a cumulative sum for each category in the table.一个常见的用法是计算表中每个类别的累积总和。 See BigQuery window function examples for reference.请参阅BigQuery window function 示例以供参考。