CASE WHEN c.pr_result IS NULL AND d.paid_num IS NULL THEN 'null' WHEN c.pr_result IS NULL THEN CONCAT('0-0\n', d.paid_num) WHEN d.paid_num IS NULL THEN CONCAT(c.pr_result, '\n') ELSE CONCAT(c.pr_result, '\n', d.paid_num) END AS num给num中的paid_num进行标红预览结果: