你能不能先去学基础?
Dim fdr As DataRow = DataTables("证书编号表").Find("身份证号码 = '" & e.DataRow("身份证号码") & "' And 申报鉴定工种 = '" & e.DataRow("申报鉴定工种") & "' And 证书编号 = '" & e.DataRow("原资格证书编号") & "' And convert(substring(证书编号,1,2),'System.Int32') <= " & Date.Today.Year - 2000 - 5)