Select a column from subquery inside select?

Question

How can I SELECT the Attr1 from subquery to the parent query? I have tried to use Average.Attr1 but doesn't work.

not a single-group group function

SELECT SUM(Report.Attr1), 
       SUM(Report.Attr2), 
       SUM(Report.Attr3), 
       0
FROM {Report}, 
(
    SELECT AVG(Report.Attr1),
           AVG(Report.Attr2),
           AVG(Report.Attr3)
    FROM Report
    WHERE 
        StartDate <= Report.Date AND
        Report.Date <= EndDate
    GROUP BY Report.Attr1, Report.Attr2, Report.Attr3
) Average
WHERE 
    StartDate <= Report.Date AND
    Report.Date <= EndDate

Answer 1

You can add aliases to those aggregate functions, so that you can use them in the outer query

SELECT SUM(avg_attr1), 
       SUM(avg_attr2), 
       SUM(avg_attr3), 
       0
FROM {Report}, 
(
    SELECT AVG(Report.Attr1) as avg_attr1,
           AVG(Report.Attr2) as avg_attr2,
           AVG(Report.Attr3) as avg_attr3
    ...

Or if you just want to limit on them, then you could use the HAVING clause together with the GROUP BY

...
      GROUP BY Report.Attr1, Report.Attr2, Report.Attr3
      HAVING AVG(Report.Attr1) > {SomeNumber}
) Average
...

Answer 2

I am not sure if this is what you want, but I get it to work by:

WITH REPORT (STARTDATE,ENDDATE,DATE1,ATTR1,ATTR2,ATTR3)AS(
SELECT DATE '2018-01-01',DATE '2018-02-01',DATE '2018-01-11', 1,2,3 FROM DUAL UNION ALL
SELECT DATE '2018-01-01',DATE '2018-02-01',DATE '2018-01-11',1,2,3 FROM DUAL UNION ALL
select date '2018-01-01',DATE '2018-02-01',DATE '2018-01-11',1,2,3 from dual 
)

SELECT SUM(Report.Attr1), 
       SUM(Report.Attr2), 
       SUM(REPORT.ATTR3), 
       0,
       average.a,average.b,average.c
FROM REPORT, 
(
    SELECT AVG(REPORT.ATTR1) A,
           AVG(REPORT.ATTR2) B ,
           AVG(Report.Attr3) c
    FROM Report
    WHERE 
        STARTDATE <= REPORT.DATE1 AND
        Report.Date1 <= EndDate
    GROUP BY Report.Attr1, Report.Attr2, Report.Attr3
) Average
WHERE 
    STARTDATE <= REPORT.DATE1 AND
    REPORT.DATE1 <= ENDDATE
    GROUP BY 0,
       average.a,average.b,average.c

Answer 3

You can refer to them by giving an Alias name. Now if you say, Average.attr you get the value corresponding to Report.Attr1

SELECT SUM(Report.Attr1), 
           SUM(Report.Attr2), 
           SUM(Report.Attr3), 
           0,
           Average.attr
    FROM {Report}, 
    (
        SELECT AVG(Report.Attr1) as attr,
               AVG(Report.Attr2),
               AVG(Report.Attr3)
        FROM Report
        WHERE 
            StartDate <= Report.Date AND
            Report.Date <= EndDate
        GROUP BY Report.Attr1, Report.Attr2, Report.Attr3
    ) Average
    WHERE 
        StartDate <= Report.Date AND
        Report.Date <= EndDate