asp.net core razor json null data trigger error

Question

I have a json whic gets data from 4 tables. one of it has no value and because of that I have nothing in my view

public async Task<JsonResult> OnGetDetailsAsync(string id1, int id2)
{
    var woplanner = await _context.WOPlanners.FirstAsync(s => s.WOMainID == id1 && s.WONumberS == id2);
    var woapprover = await _context.WOApprovers.FirstAsync(s => s.WOMainID == id1 && s.WONumberS == id2);
    var woplannerS = await _context.WOPlannerSCHs.FirstAsync(s => s.WOMainID == id1 && s.WONumberS == id2);
    var woreports = await _context.WOReports.FirstAsync(s => s.WOMainID == id1 && s.WONumberS == id2);

    WOD obj = new WOD
    {
        WOPlanner = woplanner,
        WOApprover = woapprover,
        WOPlannerSCH = woplannerS,
        WOReport = woreports
    };

    return new JsonResult(obj);
}

WOPlannerSCH has no data now, how do I fix this?