Hi Henry,

Flink does support rename column after casting.

The exception is not caused by cast. It is caused by mixing of types, for
example,  the query

> "CASE 1 WHEN 1 THEN *true* WHEN 2 THEN *'string'* ELSE NULL END"

will throw the same exception since type of true and 'string' are not same.

Best, Hequn.

On Tue, Aug 14, 2018 at 12:51 PM, 徐涛 <happydexu...@gmail.com> wrote:

> 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

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