@Query for joining two tables

Question

I am trying to join two entities in a third one using @Query method.

@Query("SELECT new com.concretepage.entity.DeptEmpDto(d.departmentId,d.departmentName,d.managerId,d.locationId,e.employeeId,e.firstName,e.lastName,e.phoneNumber,e.hireDate,e.jobId,e.salary,e.commissionPct) FROM Employee e INNER JOIN Department d")
List <DeptEmpDto> fetchEmpDeptDataInnerJoin();

You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '' at line 1.

I cannot understand where is my mistake.Any help will be appreciated :).

Answer 1

You missed the joining condition after joining tables using ON clause. So just change your query with this:

@Query("SELECT new com.concretepage.entity.DeptEmpDto(d.departmentId,d.departmentName,d.managerId,d.locationId,e.employeeId,e.firstName,e.lastName,e.phoneNumber,e.hireDate,e.jobId,e.salary,e.commissionPct) FROM Employee e INNER JOIN Department d on e.joining_column_from_table1=d.joining_column_from_table2")

Make sure to replace joining_column_from_table1 and joining_column_from_table2 with your column names from table Employee and Department respectively