SELECT v.hn, v.vn, v.vstdate
FROM vn_stat v
LEFT OUTER JOIN opitemrece o1 ON o1.vn=v.vn AND o1.icode="1510206"
LEFT OUTER JOIN opitemrece o2 ON o2.vn=v.vn AND o2.icode="1460563"
LEFT OUTER JOIN opitemrece o3 ON o3.vn=v.vn AND o3.icode="1460283"
WHERE v.vstdate BETWEEN "2011-02-01" AND "2011-02-31"
AND v.pdx="b24"
GROUP BY v.vn