…#39322)
https://github.com/apache/doris/pull/39322
## Proposed changes
```
mysql [(none)]>select round(timediff(now(),'2024-08-15')/60/60,2);
ERROR 1105 (HY000): errCode = 2, detailMessage = argument 1 requires datetimev2 type, however 'now()' is of datetime type
```
The reason is that the function parameter types were modified in
expectedInputTypes, which led to no match being found. The code here is
from a long time ago. Because the precision of datetimev2 could not be
deduced in the past, a separate implementation was made here. This code
can be safely deleted.
<!--Describe your changes.-->
## Proposed changes
Issue Number: close #xxx
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a9692a305e