I have written below query inside bigquery function. If i am removing outer query, it is working fine. But if i put outer select query, it is throwing below error,

Table-valued function SQL body without a RETURNS TABLE clause is
missing one or more explicit output column names at [2:1]

Select Project,sum(ProCount),sum(todayExecCount),sum(CurrentDateAvg),sum(thisWeekAvg),sum(thisMonthAvg),sum(lastMonthAvg) from(
           SELECT
            COALESCE(w.project, m.project, l.project,c.project,pc.project) AS Project,
            COALESCE(pc.ProCount,0) ProCount,
            COALESCE(c.todayExecCount, 0) AS todayExecCount,
            COALESCE(c.CurrentDateAvg,0) CurrentDateAvg,
            COALESCE(w.thisWeekAvg,0) thisWeekAvg ,
            COALESCE(m.thisMonthAvg,0) thisMonthAvg,
            COALESCE(l.lastMonthAvg,0) lastMonthAvg
            FROM
            ThisWeek w
            FULL OUTER JOIN         ThisMonth m         ON        w.project = m.project
            FULL OUTER JOIN         ProjectCount pc     ON        m.project = pc.project
            FULL OUTER JOIN         CurrentDate c       ON        pc.project = c.project
            FULL OUTER JOIN         LastMonth l         ON        c.project = l.project) group by project