To clear things up, I have two tables, employees
and jobs
.
In employees
I have columns firstname, lastname, employees id.
In jobs
I have columns
job_id, job_name, job_description, job_opener, job_responsible_person
where the last two are foreign keys which refer to the employees
table.
This is my SQL statement
String cmd = "SELECT je.id, firstname, lastname, job_name FROM jat.employees je" + " INNER JOIN jat.jobs jj ON je.id = jj.job_opener ";
And I fill data table with it.
What I need is adding two more columns, like second first name and second last name, in same table, but which will depend on job_responsible_p, so ON clause would be
ON je.id = jj.job_responsible_p
Is that possible in one query?
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Answer
Yes, you can join several table at once:
SELECT je.id, je.firstname, je.lastname, jj.job_name, jr.firstname, jr.lastname FROM jat.employees AS je INNER JOIN jat.jobs AS jj INNER JOIN jat.employees AS jr ON je.id=jj.job_opener AND jr.id=jj.job_responsible_person;