July 2023
Intermediate to advanced
278 pages
5h 40m
Chinese
Content preview from Trino 权威指南：原书第2版
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在
Trino
中使用
SQL
|
165
与
ANY
一样，
ALL
也有一些初看起来并不明显的细微差别。当子查询为空（即没有返回
任何行）时，
ALL
就会计算为
TRUE
；如果没有一个比较结果返回
FALSE
且至少有一个
比较结果返回
NULL
，那么
ALL
子查询的结果就是
NULL
。
ALL
最常见的另一个用法是
<>
ALL
，等价于
NOT IN
。
8.19
从表中删除数据
DELETE
语句可以删除表中的数据行。该语句提供了一个可选的
WHERE
子句来指定删除哪
些行。若不使用
WHERE
子句，则表中所有数据都会被删除：
DELETE FROM table_name [ WHERE condition ]
有些连接器不支持删除或有限支持删除。例如，
Kafka
连接器不支持删除；
Hive
连接器
只有在
WHERE
子句指定了可用于删除整个分区的分区键时才支持删除：
DELETE FROM datalake.web.page_views
WHERE view_date = DATE '2019-01-14' AND country = 'US'
8.20
小结
对你在
Trino
中可以用
SQL
做到的事感到兴奋了吗？有了本章的知识，你已经可以对
Trino
中的任何数据进行复杂的查询，并完成一些相当复杂的分析。
当然，还有更多内容等着你。请继续阅读第
9
章，了解
Trino
的函数、运算符和其他功能。
Trino权威指南 正文7z-最后.indd 165Trino权威指南 正文7z-最后.indd 165 2023-8-4 14:03:312023-8-4 14:03:31 ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.