Hi @peter.tun
Can you try below query
dtFiltered = (From row In dtInput.AsEnumerable()
Where row("Completion %").ToString() = "100"
Select dtInput.Clone().LoadDataRow(New Object() {
row("Student ID"),
row("Course Name"),
row("Course Start Date"),
row("Course Completed Date"),
row("Course Start Date (Maths)"),
row("Course Completed Date (Maths)"),
row("Completion %")
}, False)).CopyToDataTable()
Regards,