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https://issues.apache.org/jira/browse/FLINK-6813?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16326189#comment-16326189
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ASF GitHub Bot commented on FLINK-6813:
---------------------------------------
Github user sunjincheng121 commented on a diff in the pull request:
https://github.com/apache/flink/pull/4117#discussion_r161504809
--- Diff:
flink-libraries/flink-table/src/main/scala/org/apache/flink/table/codegen/calls/ScalarOperators.scala
---
@@ -702,12 +703,15 @@ object ScalarOperators {
def generateTemporalPlusMinus(
plus: Boolean,
nullCheck: Boolean,
+ typeName: SqlTypeName,
left: GeneratedExpression,
right: GeneratedExpression)
: GeneratedExpression = {
val op = if (plus) "+" else "-"
+ val AVGDAYS_PRE_MONTH = 30.5
--- End diff --
Is not a standard, I did not find the relevant norms, do you have any
suggestions?
> Add TIMESTAMPDIFF supported in SQL
> ----------------------------------
>
> Key: FLINK-6813
> URL: https://issues.apache.org/jira/browse/FLINK-6813
> Project: Flink
> Issue Type: Sub-task
> Components: Table API & SQL
> Affects Versions: 1.4.0
> Reporter: sunjincheng
> Assignee: sunjincheng
> Priority: Major
>
> TIMESTAMPDIFF(unit,datetime_expr1,datetime_expr2) Returns datetime_expr2 −
> datetime_expr1, where datetime_expr1 and datetime_expr2 are date or datetime
> expressions. One expression may be a date and the other a datetime; a date
> value is treated as a datetime having the time part '00:00:00' where
> necessary. The unit for the result (an integer) is given by the unit
> argument. The legal values for unit are the same as those listed in the
> description of the TIMESTAMPADD() function.
> * Syntax
> TIMESTAMPDIFF(unit,datetime_expr1,datetime_expr2)
> -unit
> Is the part of datetime_expr1 and datetime_expr2 that specifies the type of
> boundary crossed.
> -datetime_expr1
> Is an expression that can be resolved to a time, date.
> -datetime_expr2
> Same with startdate.
> * Example
> SELECT TIMESTAMPDIFF(year, '2015-12-31 23:59:59.9999999', '2017-01-01
> 00:00:00.0000000') from tab; --> 2
> * See more:
>
> [MySQL|https://dev.mysql.com/doc/refman/5.7/en/date-and-time-functions.html#function_timestampdiff]
> CALCITE:
> {code}
> SELECT timestampdiff(YEAR, timestamp '2019-06-01 07:01:11', timestamp
> '2020-06-01 07:01:11'),timestampdiff(QUARTER, timestamp '2019-06-01
> 07:01:11', timestamp '2020-06-01 07:01:11'),timestampdiff(MONTH, timestamp
> '2019-06-01 07:01:11',timestamp '2020-06-01 07:01:11'),timestampdiff(WEEK,
> timestamp '2019-06-01 07:01:11',timestamp '2020-06-01
> 07:01:11'),timestampdiff(DAY, timestamp '2019-06-01 07:01:11',timestamp
> '2020-06-01 07:01:11'),timestampdiff(HOUR, timestamp '2019-06-01
> 07:01:11',timestamp '2020-06-01 07:01:11'),timestampdiff(MINUTE, timestamp
> '2019-06-01 07:01:11',timestamp '2020-06-01 07:01:11'),timestampdiff(SECOND,
> timestamp '2019-06-01 07:01:11',timestamp '2020-06-01 07:01:11') FROM depts;
> | 1 | 4 | 12 | **52** | 366 | 8784 | 527040 |
> 31622400
> {code}
> MSSQL:
> {code}
> SELECT
> datediff(YEAR, '2019-06-01 07:01:11','2020-06-01 07:01:11'),
> datediff(QUARTER, '2019-06-01 07:01:11', '2020-06-01 07:01:11'),
> datediff(MONTH, '2019-06-01 07:01:11','2020-06-01 07:01:11'),
> datediff(WEEK, '2019-06-01 07:01:11', '2020-06-01 07:01:11'),
> datediff(DAY, '2019-06-01 07:01:11','2020-06-01 07:01:11'),
> datediff(HOUR, '2019-06-01 07:01:11','2020-06-01 07:01:11'),
> datediff(MINUTE, '2019-06-01 07:01:11','2020-06-01 07:01:11'),
> datediff(SECOND, '2019-06-01 07:01:11', '2020-06-01 07:01:11')
> FROM stu;
> |1 |4 |12 |**53** |366 |8784 |527040 |31622400
> {code}
> The differences I have discussed with the calcite community. And find the
> reason:
> https://stackoverflow.com/questions/26138167/is-timestampdiff-in-mysql-equivalent-to-datediff-in-sql-server.
> So, In this JIRA. we will keep consistency with calcite.
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