动态列排序

【问题】

I have this data in my table and I want to sort it using the numbers in the data.

Data unsorted

5 team team team team

team team team 2 team

team team team team 4

team 1 team team team

team team 3 team team

Data Sorted

team 1 team team team

team team team 2 team

team team 3 team team

team team team team 4

5 team team team team

有人给出解答，楼主没回复

Create this function:

CREATE FUNCTION IsNumeric (val varchar(255)) RETURNS tinyint
 RETURN val REGEXP '^(-|\\+){0,1}([0-9]+\\.[0-9]*|[0-9]*\\.[0-9]+|[0-9]+)$';
CREATE FUNCTION GetNumericOnly (val VARCHAR(255))
 RETURNS VARCHAR(255)
BEGIN
 DECLARE idx INT DEFAULT 0;
 IF ISNULL(val) THEN RETURN NULL; END IF;
 IF LENGTH(val) = 0 THEN RETURN ""; END IF;
 SET idx = LENGTH(val);
  WHILE idx > 0 DO
  IF IsNumeric(SUBSTRING(val,idx,1)) = 0 THEN
   SET val = REPLACE(val,SUBSTRING(val,idx,1),"");
   SET idx = LENGTH(val)+1;
  END IF;
  SET idx = idx - 1;
  END WHILE;
  RETURN val;
 END;

Then use it like this:

SELECT * FROM mixedvalues
ORDER BY GetNumericOnly(value)

【回答】

SQL做这种动态列的运算很不方便，如果没特别要求，建议读出来用SPL来做，把记录转成数组再取了数值类型的字段排序即可，代码简单也易懂：

A1：从表tb取数

A2：将每条记录的字段值转为序列，从该序列中取出数值成员作为A1的排序表达式进行排序

写好的脚本如何在应用程序中调用，可以参考Java 如何调用 SPL 脚本

 更多动态列的例子可参考Examples of esProc’s Assisting in Dynamic-Column-SQL Computations – Raqsoft Blog