Flink SQL does not support rename after cast type

[徐涛]

Hi All,
        I am working on a project based on Flink SQL, but found that I can`t 
rename column after casting, the code is as below:
        cast(json_type as INTEGER) as xxx
        
        And the following exception is reported:
        org.apache.calcite.runtime.CalciteContextException: From line 4, column 
6 to line 11, column 38: Illegal mixing of types in CASE or COALESCE statement

        I want to know that does Flink do not support this function because I 
think it is a common case? Is there a way to accomplish this function?
        Thank a lot.

Best
Henry Xu