SELECT P.PERSONNAME, D.DEPARTMENTNAME, S.SALARY, AVG(S.SALARY) FROM PERSON P LEFT OUTER JOIN DEPARTMENT D ON P.DEPARTMENTID = D.DEPARTMENTID LEFT OUTER JOIN SALARY S ON P.PERSONID = S.PERSONID GROUP BY D.DEPARTMENTID;
SELECT P.PERSONNAME, D.DEPARTMENTNAME, S.SALARY, AVG(S.SALARY) as AVGSALARY FROM PERSON P LEFT OUTER JOIN DEPARTMENT D ON P.DEPARTMENTID = D.DEPARTMENTID LEFT OUTER JOIN SALARY S ON P.PERSONID = S.PERSONID GROUP BY P.PERSONID;
немогу понять как применить avg SELECT P.PERSONNAME, D.DEPARTMENTNAME, S.SALARY FROM PERSON P LEFT OUTER JOIN DEPARTMENT D ON P.DEPARTMENTID = D.DEPARTMENTID LEFT OUTER JOIN SALARY S ON P.PERSONID = S.PERSONID;
Это надо отдельным запросом писать, и потом JOIN-ить к основному запросу