MySQL: count data from A month until B month

[FreddyFran]

regarding to this question, i have a problem if use that query for count some data.How to make it can count data for ex. from 2010-01 until 2010-05?after use that query the show as null.this is my query:\[code\]SELECT id, Line, COUNT( Serial_number ) AS Qty, SUM(S), SUM(A), SUM(B), SUM(C), (SUM( S ) + SUM( A ) + SUM( B ) * 0.4 + SUM( C ) * 0.1) / COUNT( Serial_number ) AS QPFROM `inspection_report`\[/code\]