How to fetch data from one child table to other child table of same doctype

I have two child tables in same doc type. I want to fetch start date and end date from on child table to other. Is it possible? which script i can use?

You can view do by this script

frappe.ui.form.on("[CHILD_TABLE_TARGET_DOCTYPE]", {
	[CHILD_TABLE_LINK_FIELD]: function(frm, cdt, cdn) {
		var row = locals[cdt][cdn];
			frappe.model.with_doc("[SOURCE_DOCTYPE]", row.[CHILD_TABLE_LINK_FIELD], function() {
				var doc = frappe.model.get_doc("[SOURCE_DOCTYPE]", row.[CHILD_TABLE_LINK FIELD]);
				$.each(doc.[SOURCE_DOCTYPE_CHILD_TABLE] || [], function(i, r) {
						var df = frappe.meta.get_docfield("CHILD_TABLE_TARGET_DOCTYPE","[TARGET_CHILD_TABLE_CUSTOM_FIELD]",;
						df.options += ["\n" + r.[TARGET_CHILD_TABLE_CUSTOM_FIELD]];

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I have to fetch this two fields to below table but there is no link except i get currently other fields fetched automatically when press generate schedule button. I tired code but i am getting error.