SQL排序字符串和数字

Question

If I have a list of 1,2,3,4,5,K and I want it ordered like K,1,2,3,4,5 how can I do this in SQL? Those values are the only ones in the SQL table. This is in MySQL, but other databases are also welcomed.

Answer 1

There's no integer dection function in mysql, so you'll have to do something like this. Assuming your column is varchar or the like, you could something simple like this

ORDER BY CASE WHEN field REGEXP '^-?[0-9]+$' THEN field ELSE '0'+field END

Answer 2

In Oracle, you could do:

ORDER BY CASE WHEN column='K' THEN 0 ELSE TO_NUMBER(column) END

Other systems presumably have similar constructs.

Answer 3

If you need to sort the SELECT's result, then you might just declare your custom sorting rules in ORDER BY statement.

Here's an example: http://www.emadibrahim.com/2007/05/25/custom-sort-order-in-a-sql-statement/

The idea is to assign your own priority to each item.

Bear in mind that it might be dependant on the actual SQL server.

Answer 4

Here's one that works in SQLite:

 select v1.* from (
   select t3.*, (case when value = 'K' then '0' else value end) normalized_val 
   from t3) v1 
 order by v1.normalized_val;