[FLINK-27015] Fix exception for casting timestamp to decimal in Hive dialect

• Type: Sub-task
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 1.16.0
• Fix Version/s: 1.16.0
• Component/s: Connectors / Hive
• Labels: pull-request-available
• Assignee: luoyuxia
• Reporter: luoyuxia
• Created: 02/Apr/22 11:12
• Updated: 16/Aug/22 13:12
• Resolved: 16/Aug/22 13:12

Description

In hive, it's support to cast timestamp to decimal implictly with following sql:

create table t1 (c1 DECIMAL(38,6));
create table t2 (c2 TIMESTAMP);
insert into t1 select * from t2;
-- or
select cast(cast('2012-12-19 11:12:19.1234567' as timestamp) as decimal(30,8))

But it'll throw exception "The cast conversion from TIMESTAMP type to NUMERIC type is not allowed" with Hive dialect in Flink. 

Issue Links

• links to: GitHub Pull Request #19298
• links to: GitHub Pull Request #20571