[jira] [Commented] (FLINK-10216) Add REGEXP_MATCH in TableAPI and SQL

["vinoyang (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/FLINK-10216?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16593129#comment-16593129 ] 

vinoyang commented on FLINK-10216:
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[~juho.autio.r] Flink already has a function for regular matching, called "similar to", which is provided by Apache Calcite. Reference documentation: https://ci.apache.org/projects/flink/flink-docs-release-1.6/dev/table/sql.html#built-in-functions

> Add REGEXP_MATCH in TableAPI and SQL
> ------------------------------------
>
>                 Key: FLINK-10216
>                 URL: https://issues.apache.org/jira/browse/FLINK-10216
>             Project: Flink
>          Issue Type: Sub-task
>            Reporter: Juho Autio
>            Priority: Major
>
> Here's a naive implementation:
> {code:java}
> public class RegexpMatchFunction extends ScalarFunction {
>     // NOTE! Flink calls eval() by reflection
>     public boolean eval(String value, String pattern) {
>         return value != null && pattern != null && value.matches(pattern);
>     }
> }
> {code}
> I wonder if there would be a way to optimize this to use {{Pattern.compile(value)}} and use the compiled Pattern for multiple calls (possibly different values, but same pattern).
> h3. Naming
> Should regex functions be prefixed with {{regexp_}} or {{regex_}}? See also: [https://github.com/apache/flink/pull/6448#issuecomment-415972833]



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