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https://issues.apache.org/jira/browse/FLINK-6891?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16077469#comment-16077469
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ASF GitHub Bot commented on FLINK-6891:
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Github user sunjincheng121 commented on the issue:
https://github.com/apache/flink/pull/4122
I have rebase the code and update the PR.
> Add LOG(X) supported in SQL
> ---------------------------
>
> Key: FLINK-6891
> URL: https://issues.apache.org/jira/browse/FLINK-6891
> Project: Flink
> Issue Type: Sub-task
> Components: Table API & SQL
> Affects Versions: 1.4.0
> Reporter: sunjincheng
> Assignee: sunjincheng
>
> LOG(X), LOG(B,X)
> If called with one parameter, this function returns the natural logarithm of
> X. If X is less than or equal to 0.0E0, the function returns NULL and (as of
> MySQL 5.7.4) a warning “Invalid argument for logarithm” is reported.
> The inverse of this function (when called with a single argument) is the
> EXP() function.
> If called with two parameters, this function returns the logarithm of X to
> the base B. If X is less than or equal to 0, or if B is less than or equal to
> 1, then NULL is returned.
> * Example:
> LOG(2) -> 0.69314718055995
> LOG(-2) -> NULL
> LOG(2,65536) -> 16
> LOG(10,100) -> 2
> LOG(1,100) -> NULL
> * See more:
> ** [MySQL|
> https://dev.mysql.com/doc/refman/5.7/en/mathematical-functions.html#function_log]
> --NOTE-- In this JIRA. NULL case will throw IllegalArgumentException.
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