使用派生表进行完全外部联接-MySQL

Question

I am having trouble with a full outer join on two tables, the sql i am using is as follows:

SELECT
  a.sryear,
  b.reqyear,
  a.mid,
  b.description,
  sum(a.kmq + b.rmq) as sum 
FROM
  (select
    EXTRACT(YEAR 
  FROM
    t.date) AS srYear,
    m.materialid as mid,
    m.description,
    sum(km.quantity) as kmq 
  FROM
    kit k,
    kitmaterial km,
    materials m,
    service s,
    transaction t 
  WHERE
    t.serviceid=s.serviceid 
    AND s.kitid=k.kitid 
    AND k.kitid=km.kitid 
    AND km.materialid=m.materialid 
  GROUP BY
    srYear,
    m.materialid 
  ORDER BY
    srYear,
    m.materialid) as a FULL 
OUTER JOIN
  , (
    SELECT
      EXTRACT(YEAR 
    FROM
      r.datecreated) AS reqYear,
      m.materialid as mid,
      m.description as description,
      sum(rm.quantity) as rmq 
    FROM
      requisitionmaterial rm,
      materials m,
      requisition r 
    WHERE
      rm.materialid=m.materialid 
      AND r.requisitionid=rm.requisitionid 
    GROUP BY
      reqYear,
      m.materialid 
    ORDER BY
      reqYear,
      m.materialid
  ) as b 
    ON a.mid=b.mid 
    AND a.sryear=b.reqyear;

Any assistance rendered will be appreciated.

Thank you!!

Answer 1

under the condition that inline view a and b works as you expected, there is one problem.

SELECT
  ....
  sum(a.kmq + b.rmq) as sum 

SUM() is aggregation function. So can't be used without GROUP BY . did you mean this?

SELECT
  ....
  a.kmq + b.rmq as `sum`

otherwise, you should use GROUP BY with some column