更改：未关联工作项需包含外键为0的数据

app/services/api/pm/sprint_issues/list_service.rb

@@ -33,7 +33,7 @@ class Api::Pm::SprintIssues::ListService < ApplicationService
 
   private
   def issue_query_data
-     issues = @category == "unlink" ? Issue.where(pm_project_id: @pm_project_id, pm_sprint_id: nil) : Issue.where(pm_project_id: @pm_project_id).where.not(pm_sprint_id: nil)
+     issues = @category == "unlink" ? Issue.where(pm_project_id: @pm_project_id, pm_sprint_id: [nil, 0]) : Issue.where(pm_project_id: @pm_project_id).where.not(pm_sprint_id: [nil, 0])
 
      issues = issues.where(pm_issue_type: @pm_issue_type) if @pm_issue_type.present?