[Boost-users] "newbie" Build Boost Matrix

hi all   After executing the below sql query in c++, the printed results are:   WITH rnum AS (SELECT s.ISN, s.Date, ClosedPrice, row_number() OVER (partition BY s.ISN ORDER BY s.ISN, s.Date DESC) AS rownumber FROM SecurityData s INNER JOIN PortfolioHoldings p ON s.ISN = p.ISN WHERE p.Pfid = 1876) SELECT DISTINCT ISN, Date, ClosedPrice FROM rnum WHERE rownumber <= 250))   //ID       Date            Price US345 2014-08-17 342 US345 2014-08-16 310 ... FR123  2014-08-17  18.20 FR123 2014-08-16   15   Does anyone know how to build a price matrix for the IDs like:?             |342  18.20| MAT=|310   15    |           |...       ...    |   Your feedback would be very appreciated   Cheers