sql - 按查询的where子句中的字段顺序对sql查询的结果进行排序

Question

我想根据查询的包含对此查询的结果进行排序：

这里是 ：

SELECT a from Frais a where a.libelle = 'FRET' or a.libelle = 'Douane' or a.libelle = 'Transitaire'

我想要有FRET第一和Douane之后的记录等等

order by libelle 

不能解决它根据字母顺序 asc 或 desc 对它们进行排序的问题

Answer 1

一种选择是使用CASE语句：

SELECT * 
FROM Frais a 
WHERE a.libelle = 'FRET' 
   OR a.libelle = 'Douane' 
   OR a.libelle = 'Transitaire'
ORDER BY 
   CASE 
     WHEN a.libelle = 'FRET' THEN 1
     WHEN a.libelle = 'Douane' THEN 2
     WHEN a.libelle = 'Transitaire' THEN 3
   END

Answer 2

SELECT a from Frais a where a.libelle = 'FRET' or a.libelle = 'Douane' or a.libelle = 'Transitaire'
order by case a.libelle when 'FRET' then 0 when 'Douane' then 1 when 'Transitaire' then 2 end

Answer 3

您也可以通过将值放在具有显式排序的“临时”表中来做到这一点：

select f.*
from frais f join
     (select 'FRET' as val, 1 as ord union all
      select 'Douane', 2 union all
      select 'Transitaire', 3
     ) vals
     on f.libelle = vals.val
order by vals.ord