单个中位数

src/main/resources/mapper_dao/FirstAidRecordDao.xml

@@ -68,7 +68,8 @@
         (
         select
         ROUND((r1.answer - r2.answer)/60000, 2) as val
-        from t_qcp_first_aid a, t_qcp_first_aid_record r1 , t_qcp_first_aid_record r2
+        from t_qcp_first_aid a, t_qcp_first_aid_record r1 , t_qcp_first_aid_record r2,
+        (SELECT @rownum:=0) r
         where a.id = r1.first_aid_id and r1.question_code = #{minuendCode}
         and a.id = r2.first_aid_id and r2.question_code = #{subtractionCode}
         and r1.answer + 0 >= #{startTime} and r1.answer + 0 <= #{endTime}
@@ -77,9 +78,8 @@
         </foreach>
         AND a.value_type = 0 and a.data_status in (1, 3, 5, 6)
         and a.rec_status = 0 and r1.rec_status = 0 and r2.rec_status = 0
-        )d,
-        (SELECT @rownum:=0) r
-        ORDER BY d.val
+        order by r1.answer - r2.answer asc
+        )d
         ) as dd
         WHERE dd.row_number IN ( FLOOR((@total_rows+1)/2), FLOOR((@total_rows+2)/2) )
     </select>