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liyang commented on KYLIN-5279: ------------------------------- NULL is smaller or larger? It depends. The answe depends on the SQL vendor. Below is a summary from [https://learnsql.com/blog/how-to-order-rows-with-nulls/] * PostgreSQL / Oracle — NULL is larger, by default * MySQL / SQL Server — NULL is smaller, by default Of course, the default behavior is configurable in most of these products. The PR looks good as it lets KYLIN behavior configurable as well. 👍 > Default null collation for Kylin5.0 sqls should be null-last for ASC order > and null-first for DESC order. > --------------------------------------------------------------------------------------------------------- > > Key: KYLIN-5279 > URL: https://issues.apache.org/jira/browse/KYLIN-5279 > Project: Kylin > Issue Type: Bug > Components: Query Engine > Reporter: Zhenning Zhang > Assignee: Zhenning Zhang > Priority: Major > Fix For: 5.0-alpha > > Attachments: image-2022-10-20-15-12-12-967.png > > > according to pgsql: > [https://www.postgresql.org/docs/current/queries-order.html] > "By default, null values sort as if larger than any non-null value; that is, > {{NULLS FIRST}} is the default for {{DESC}} order, and {{NULLS LAST}} > otherwise." > currently, the result is: > !image-2022-10-20-15-12-12-967.png|width=1320,height=743! -- This message was sent by Atlassian Jira (v8.20.10#820010)