SQL ORDER by STRING奇怪的语法

Question

是否有一个不那么丑陋/更程序化的方法来解决这个问题:

ORDER BY CASE 
 WHEN lessonID = 'lesson_1' Then 1  
 WHEN lessonID = 'lesson_novid_1' Then 2 
 WHEN lessonID = 'lesson_2' Then 3 
 WHEN lessonID = 'lesson_novid_2' Then 4 
 WHEN lessonID = 'lesson_3' Then 5 
 WHEN lessonID = 'lesson_novid_3' Then 6 
 WHEN lessonID = 'lesson_4' Then 7 
 WHEN lessonID = 'lesson_novid_4' Then 8 
 WHEN lessonID = 'lesson_5' Then 9 
 WHEN lessonID = 'lesson_novid_5' Then 10 
 WHEN lessonID = 'lesson_6' Then 11 
 WHEN lessonID = 'lesson_novid_6' Then 12
 WHEN lessonID = 'lesson_7' Then 13 
 WHEN lessonID = 'lesson_novid_7' Then 14
 WHEN lessonID = 'lesson_8' Then 15
 WHEN lessonID = 'lesson_novid_8' Then 16
 WHEN lessonID = 'lesson_9' Then 17
 WHEN lessonID = 'lesson_novid_9' Then 18
 WHEN lessonID = 'lesson_10' Then 19
 WHEN lessonID = 'lesson_novid_10' Then 20
 WHEN lessonID = 'lesson_11' Then 21
 WHEN lessonID = 'lesson_novid_11' Then 22 
 WHEN lessonID = 'lesson_12' Then 23 
 WHEN lessonID = 'lesson_novid_12' Then 24
End ASC

Answer 1

尝试找到数字并将其转换为整数:

ORDER BY
    CAST(REPLACE(REPLACE(lessonID, 'lesson_', ''), 'novid_', '') AS INT),
    lessonID

看到它在线工作:sqlfiddle

请注意,此查询将无法使用索引来执行排序.您可以考虑使用计算列并将其编入索引以提高性能.