如何连接DATE和TIME以在JPA查询中形成DATETIME（TIMESTAMP）？

I have two fields in a database to store Date and Time. The former has its Time part set to zero, and the latter its Date part set to null (i.e. 1970/1/1). God only knows why the original developer did it this way, and I can't change the table. In a JPA query I need to compare a Timestamp to those two fields as if they were one single DateTime field. In SQL Server I'd do something like this:I have two fields in a database to store Date a