Zhenghua Gao created CALCITE-3881:
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Summary: SqlFunctions#addMonths yields incorrect results in some
corner case
Key: CALCITE-3881
URL: https://issues.apache.org/jira/browse/CALCITE-3881
Project: Calcite
Issue Type: Bug
Components: avatica
Affects Versions: avatica-1.16.0
Reporter: Zhenghua Gao
SqlFunctions#addMonths use DateTimeUtils#ymdToUnixDate to calculate the
JDN(julian day number). But in some corner cases it yields incorrent results.
The root cause is: the algorithm of DateTimeUtils#ymdToUnixDate requires
reasonable month(1 to 12)[1], but SqlFunctions#addMonths may pass in a month
out of the reasonable range.
BTW: I didn't find the reference of the original paper of the algorithm, but an
jdn explanation. Please correct me if anyone can find the original paper.
The following case can reproduce the bug:
{code:java}
@Test public void testAddMonths() {
checkAddMonths(2019, 9, 1, 2020, 3, 1, 6);
} {code}
[1]
[http://www.cs.utsa.edu/~cs1063/projects/Spring2011/Project1/jdn-explanation.html]
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