如何删除MySQL字段中的前导和尾随空格?

我有一个包含两个字段(国家和ISO代码)的表:

I have a table with two fields (countries and ISO codes):

Table1

   field1 - e.g. 'Afghanistan' (without quotes)
   field2 - e.g. 'AF'(without quotes)

在某些行中，第二个字段在开头和/或结尾处都有空格，这会影响查询.

In some rows the second field has whitespace at the start and/or end, which is affecting queries.

Table1

   field1 - e.g. 'Afghanistan' (without quotes) 
   field2 - e.g. ' AF' (without quotes but with that space in front)

(在SQL中)有没有一种方法可以遍历表格并在field2中查找/替换空白?

Is there a way (in SQL) to go through the table and find/replace the whitespace in field2?