Filtering based on child table data

how to filter the contents bases on child table field?

for me having one sprint table .it includes a child table sprint_task .I want to filter the sprints based on projects (as we are doing in task). But in case of task erpnext is using tablename.project . But in my case the project field is inside the child table . Now how can i do this? please help me

You should be able to find many of these in frappe wiki
Try below, change your field name

me.frm.set_query(“sprint”, “sprint_task”, function(doc, cdt, cdn) {
var d = locals[cdt][cdn];
return {
filters: {project: d.project}