Mysql命令不工作

Question

我有一个MySQL表|源|目的地|距离。邮政编码可以像这样在源列或目标列中。当我尝试按顺序输出时，输出就像下面显示的那样，而不是最后一行。我该如何解决这个问题。

1. 来源|目的地|距离
2. DYRFG | DV116BL | 5.6
3. DH34G | DV116BL | 4.0

4. DV116 | DH5ADZZ | 7.0

   Select
   healthcare.address_matrix.*
   From
   healthcare.address_matrix
   Where
   (healthcare.address_matrix.source_postcode = 'Dv116BL') Or
   (healthcare.address_matrix.dest_postcode = 'Dv116BL')
   Order By
   healthcare.address_matrix.distance
   

Answer 1

如果没有按字段顺序提取订单，订单将是随机的。 我认为如果您明确命名并重命名您选择和订购的字段，将会有所帮助。不要使用* construct。

Answer 2

由于距离是一个varchar，你应该尝试按顺序进行排序：

Order By CAST(`healthcare.address_matrix.distance` AS SIGNED) DESC

Answer 3

将列转换为decimal

Select healthcare.address_matrix.* From healthcare.address_matrix Where (healthcare.address_matrix.source_postcode = 'Dv116BL') Or (healthcare.address_matrix.dest_postcode = 'Dv116BL') Order By CAST(healthcare.address_matrix.distance AS DECIMAL(5,2)) DESC