drill-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From jaltekruse <...@git.apache.org>
Subject [GitHub] drill pull request: DRILL-4551: Implement new functions (cot, rege...
Date Wed, 30 Mar 2016 18:50:54 GMT
Github user jaltekruse commented on a diff in the pull request:

    --- Diff: exec/java-exec/src/main/java/org/apache/drill/exec/expr/fn/impl/DateTypeFunctions.java
    @@ -40,6 +41,36 @@
     public class DateTypeFunctions {
    +    /**
    +     * Function to check if a varchar value can be cast to a date.
    +     *
    +     * At the time of writing this function, several other databases were checked
    +     * for behavior compatibility. There was not a consensus between oracle and
    +     * Sql server about the expected behavior of this function, and Postgres
    +     * lacks it completely.
    +     *
    +     * Sql Server appears to have both a DATEFORMAT and language locale setting
    +     * that can change the values accepted by this function. Oracle appears to
    +     * support several formats, some of which are not mentioned in the Sql
    +     * Server docs. With the lack of standardization, we decided to implement
    +     * this function so that it would only consider date strings that would be
    +     * accepted by the cast function as valid.
    +     */
    +    @SuppressWarnings("unused")
    +    @FunctionTemplate(name = "isdate", scope = FunctionTemplate.FunctionScope.SIMPLE,
    --- End diff --
    I couldn't find a definite answer on that in the oracle docs, and I didn't have an oracle
install to verify on. This Sql Server page is clear that they do return 0 on null and I assume
oracle is the same, will update the patch. https://msdn.microsoft.com/en-us/library/ms187347.aspx

If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastructure@apache.org or file a JIRA ticket
with INFRA.

View raw message