Hi Is there a way to convert epoch time to timestamp while converting datastream to table using API I need to use it define schema and set watermark

You can columnByExpression followed by watermark while defining Schema object

Schema schema = Schema.newBuilder()
                .fromResolvedSchema(table.getResolvedSchema())
                .columnByExpression("time_ltz", "PROCTIME()")
                 .watermark("time_ltz","PROCTIME()")
                .build();

Here you can define your time function for example I have took processing time

Ok so in column by expression I need to write my custom function?