您可以尝试

  SELECT AVG（CONVERT（
 REPLACE（REPLACE（value，'。'，''），'，'，'。'），
 DECIMAL（10,2）））
 FROM`table` 
 WHERE`group` = 1 
 

In a MySQL-table I have a VARCHAR-column with different values, which may represent String-, Integer-, Float-, Whatever-Values. These Values are written as a language-specific String into the Database, this means a float-value of 123.45 may be written as a String like "123,45" in german language (using VB.Net...)

As I need average values of float-values wich are in the same group: How can I cast such a string to a FLOAT within MySQL? Simply AVG(CONVERT(value, DECIMAL)) won't work (returns 99.00000), conversion to FLOAT is not possible.

Charset is utf8, Collation is utf8_general_ci.

Sample table:

id | value  | group
1  | 122,45 | 1
2  |  66,34 | 1
3  | blabla | 2
4  | 109,21 | 1
5  | bababa | 2

Goal: somethig like SELECT AVG(CONVERT(value, DECIMAL)) FROM table WHERE (group=1) should result in 99.333333, not 99.

Any Ideas?

Christoph

PS.: I did not make that database-layout...

You could try

SELECT AVG(CONVERT(
    REPLACE(REPLACE(value, '.', ''), ',', '.'), 
    DECIMAL(10,2))) 
FROM `table`
WHERE `group`=1