Performance trying to do a 'best match'

[tabreaz]

4 (country zone 4)
44 (UK)
4424 (UK London)
442467 (UK London Mobile)

The other approach is to group the data with certain category by adding a column.

as i said u can add a column with categorized the data, for example

U can add one column let us say category
For international number this column can contain one flag say one
For national number it can contain other value.

Like that

If u know the type of call then u can include that category in SQL statement. and u can add an index on category