SELECT
approver_id,
approvable_type,
CASE position
  WHEN 1 THEN ABS(TIMESTAMPDIFF(HOUR, approvals.approval_date, requisition_headers.last_submitted_at))
  ELSE ( SELECT ABS(TIMESTAMPDIFF(HOUR, approvals.approval_date, a.approval_date)) FROM approvals a
         WHERE a.approvable_type = 'RequisitionHeader'
               AND a.approvable_id = approvals.approvable_id
               AND approvals.position-1 = a.position LIMIT 1 )
  END AS elapsed
FROM
  approvals
INNER JOIN requisition_headers ON approvals.approvable_id = requisition_headers.id
WHERE
  approvable_type = 'RequisitionHeader'
  AND approvals.status = 'approved'
  AND approvals.approval_method NOT IN ('escalated', 'auto')
  AND approvals.type NOT IN ('OverrideApproval', 'SelfApproval')
  AND approvals.approver_type NOT IN ('RemoteApprover', 'CallOut')


SELECT
approver_id,
approvable_type,
CASE position
  WHEN 1 THEN ABS(TIMESTAMPDIFF(HOUR, approvals.approval_date, invoice_headers.last_submitted_at))
  ELSE ( SELECT ABS(TIMESTAMPDIFF(HOUR, approvals.approval_date, a.approval_date)) FROM approvals a
         WHERE a.approvable_type = 'InvoiceHeader'
               AND a.approvable_id = approvals.approvable_id
               AND approvals.position-1 = a.position LIMIT 1 )
  END AS elapsed
FROM
  approvals
INNER JOIN invoice_headers ON approvals.approvable_id = invoice_headers.id
WHERE
  approvable_type = 'InvoiceHeader'
  AND approvals.status = 'approved'
  AND approvals.approval_method NOT IN ('escalated', 'auto')
  AND approvals.type NOT IN ('OverrideApproval', 'SelfApproval')
  AND approvals.approver_type NOT IN ('RemoteApprover', 'CallOut')


SELECT
approver_id,
approvable_type,
CASE position
  WHEN 1 THEN ABS(TIMESTAMPDIFF(HOUR, approvals.approval_date, expense_reports.last_submitted_at))
  ELSE ( SELECT ABS(TIMESTAMPDIFF(HOUR, approvals.approval_date, a.approval_date)) FROM approvals a
         WHERE a.approvable_type = 'ExpenseReport'
               AND a.approvable_id = approvals.approvable_id
               AND approvals.position-1 = a.position LIMIT 1 )
END AS elapsed
FROM
  approvals
INNER JOIN expense_reports ON approvals.approvable_id = expense_reports.id
WHERE
  approvable_type = 'ExpenseReport'
  AND approvals.status = 'approved'
  AND approvals.approval_method NOT IN ('escalated', 'auto')
  AND approvals.type NOT IN ('OverrideApproval', 'SelfApproval')
  AND approvals.approver_type NOT IN ('RemoteApprover', 'CallOut')