[HIVE-18304] datediff() UDF returns a wrong result when dealing with a (date, string) input

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Duplicate
• Fix Version/s: 2.3.0
• Component/s: UDF
• Assignee: Hengyu Dai
• Reporter: Hengyu Dai
• Due: 19/Dec/17
• Created: 19/Dec/17 10:02
• Updated: 20/Dec/17 15:11
• Resolved: 20/Dec/17 15:11

Description

for date type argument, datediff() use DateConverter to convert input to a java Date object,
for example, a '2017-12-18' will get 2017-12-18T00:00:00.000+0800
for string type argument, datediff() use TextConverter to convert a string to date,
for '2012-01-01' we will get 2012-01-01T08:00:00.000+0800
now, datediff() will return a number less than the real date diff
we should use TextConverter to deal with date input too.

reproduce:

select datediff(cast('2017-12-18' as date), '2012-01-01'); --2177

select datediff('2017-12-18', '2012-01-01'); --2178