Using custom dialect function in hibernate @Formula

Question

I defined my custom dialect for HSQLDB:

public class CustomHSQLDialect extends HSQLDialect {

    public CustomHSQLDialect () {
        super();
        registerFunction("datediffsec", new SQLFunctionTemplate(
                StandardBasicTypes.DOUBLE, "cast((?1 - ?2) AS INTERVAL SECOND)"));
    }
}

I defined configuration:

hibernate.dialect=custom.dialect.CustomHSQLDialect 

Then I'm trying to use it in @Formula:

@Formula("case status when 'ACTIVE' then datediffsec(now(), creationDateTime) when 'CLEARED' then datediffsec(clearedDateTime, creationDateTime) end")

But I catch exception:

Caused by: java.sql.SQLSyntaxErrorException: user lacks privilege or object not found: DATEDIFFSEC

What I do wrong?

Answer 1

I don't know whether you can create this function as an SQL expression in Hibernate.

But supposing you could, this expression is wrong as far as HSQLDB is concerned.

A correct expression would be like:

 (?1 - ?2) INTERVAL SECOND

Also note there is already a TIMESTAMPDIFF function in HSQLDB which allows you to specify seconds as the unit.