Passing a query as a query parameter in JPQL Native Query

I’m trying to pass a query as a string parameter in another JPQL native query.

@Query(value = "SELECT (:query)", nativeQuery = true)
BigDecimal getTotal(@Param("query") String query);

So the resulting query would be something like the query below that returns me a value

SELECT (50 * (SELECT COUNT(*) FROM SOMETABLE))

but what I’m getting in return is only the string of :query parameter and not the result of the executed complete query.

Answer

1. Create an interface for a custom repository SomeRepositoryCustom

public interface SomeRepositoryCustom {

    BigDecimal getTotal(String sql);

}

2. Create an implementation of SomeRepositoryCustom

@Repository
class SomesRepositoryCustomImpl implements SomeRepositoryCustom {

    private JdbcTemplate template;

    @Autowired
    public SomesRepositoryCustomImpl(JdbcTemplate template) {
        this.template = template;
    }

    @Override
    public BigDecimal getTotal(String sql) {
        return template.queryForObject(sql, BigDecimal.class);
    }

}

3. Extend your JpaRepository with SomeRepositoryCustom

@Repository
public interface SomeRepository extends JpaRepository, SomeRepositoryCustom {

}

to run a query

someRepository.getTotal("SELECT (50 * (SELECT COUNT(*) FROM SOMETABLE))");