RegEx for matching Germany or Austria or CH Postcodes - regex

Question

It is about my site, it is a ad portal and 3 geodata are installed in the system: Germany, Switzerland and Austria.
When I look for an advertisement in Germany, everything works correctly, I'm looking for zip code 68259 and a radius of 30 km. The results are correct, it shows all ads from 68259 Mannheim and the radius of 30 km.
Problem: The problem exists when I search in Switzerland or Austria: I search for the postal code 6000 Lucerne 1 PF and a radius of 30 km ... the results are wrong, I also find ads from Munich or Frankfurt which correspond to 300-500 km radius! I think the mistake is somewhere in the regex postal verification! Any advice what could be wrong???
// Germany Postcode
preg_match('/\b((?:0[1-46-9]\d{3})|(?:[1-357-9]\d{4})|(?:[4][0-24-9]\d{3})|(?:[6][013-9]\d{3}))\b/is', $this->search_code, $output);
if(!empty($output[0])){
$this->search_code = $output[0];
}else{
// Switzerland, Austria Postcode
preg_match('/\d{4}/', $this->search_code, $at_ch);
if(!empty($at_ch[0])){
$this->search_code = $at_ch[0];
}
}

Answer 1

The following regex will match codes for DE, CH & AU:
'/\b((?:0[1-46-9]\d{3})|(?:[1-357-9]\d{4})|(?:[4][0-24-9]\d{3})|(?:[6][013-9]\d{3})|(?:\d{4}))\b/is'
Examples
68259 Mannheim -> 68259
6000 Lucerne 1 PF -> 6000
1234 Musterstadt -> 1234