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From:Michael Stassen Date:November 19 2005 8:55pm
Subject:Re: Mysql Finding the country name from country prefix
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Rhino wrote:
> 
> ----- Original Message ----- From: "Michael Stassen" 
> <Michael.Stassen@stripped>
> To: "Rhino" <rhino1@stripped>
> Cc: "abhishek jain" <mail@stripped>; <mysql@stripped>
> Sent: Saturday, November 19, 2005 1:11 PM
> Subject: Re: Mysql Finding the country name from country prefix
> 
> 
>> Rhino wrote:
>>
>>>
>>> ----- Original Message ----- From: "abhishek jain" <mail@stripped>
>>> To: <mysql@stripped>
>>> Sent: Saturday, November 19, 2005 8:10 AM
>>> Subject: Mysql Finding the country name from country prefix
>>>
>>>
>>>> Hi Friends,
>>>> I have a ticky mysql problem.
>>>> I need to find the country name from the country prefix so eg. i have a
>>>> mysql table with prefix and name as the coumns and with datas like :
>>>> Prefix,  Name
>>>> 1          USA
>>>> 11        XYZ
>>>> 44        UK
>>>> 91        India
>>>> 92        Pakistan
>>>> 123      ZXF
>>>> and i have a number like 911122334455 and i need t match that to india.
>>>> I cannt do that directly by this statement select name from
>>>> country_table where prefix='91'; for the simple reason as i do not have
>>>> the length or the no. of digits the prefix is beforehand.
>>>> Pl. help me out.
>>>> Quick help will be appreciated.
>>>
>>>
>>> You are not explaining your problem very clearly at all, particularly 
>>> why you think this is a MySQL problem.
>>>
>>> It looks to me as if you are trying to parse a phone number and 
>>> determine from the first few digits what country that phone number 
>>> represents.  You already have a table that gives you the country code 
>>> for each country and it shows clearly that 91 is the country code for 
>>> India. As for the length of the country code, surely you can easily 
>>> calculate that 91 has two digits in it.
>>>
>>> If you are saying that you have only a string of digits and need to 
>>> determine the country in which that phone number originates without 
>>> any further information, all I can say is good luck. The fact is that 
>>> people write their phone numbers in many different ways. Here in 
>>> Canada, if I'm giving my number to someone who lives within my city 
>>> or region, I'm likely to give them only the last seven digits, e.g. 
>>> 5551212. If I wanted to give my number to someone farther away in 
>>> Canada, the US, or the Caribbean, I'd give them 5195551212 since we 
>>> all share the same country code, 1. If I wanted to give my number to 
>>> someone in some other foreign country, I'd give them 15195551212. So, 
>>> right away, you have three different ways to express the phone number 
>>> all of which are accurate and complete in their own context. If you 
>>> parsed the first example, you might assume that I am in Brazil, 
>>> because '55' is the country code for Brazil. (Country codes '5' and 
>>> '555' are not in use at present.) If you parsed 519-555-1212, you 
>>> wouldn't find anything because there is no country code '5', '51', or 
>>> '519' currently in use. If you tried to parse '15195551212', you'd 
>>> think I was in the US, Canada, or one of the Caribbean countries 
>>> since '1' is the code for those countries. (There is is no '15' or 
>>> '151' country code at present.) Therefore, the phone number _by 
>>> itself_ is next to useless to you unless you are absolutely certain 
>>> that the phone number is complete and includes the country code, 
>>> area/city code and local number.
>>>
>>> None of that is a MySQL problem. The problem lies in your data 
>>> acquisition technique. If you have to parse phone numbers, the input 
>>> forms you use have to ensure that the user supplies the entire phone 
>>> number; ideally, that number would be supplied in different fields, 
>>> one of which would be the country code. Then you would have no 
>>> problem except making sure that the user has supplied their own phone 
>>> number and not someone elses. (The number I used in my examples, 
>>> 15195551212, is the directory assistance phone number for my area, 
>>> not my own phone number.)
>>>
>>> So, unless I've misunderstood what you are asking, I don't think we 
>>> can help you very much. There is no function in MySQL or any other 
>>> database I have used that can calculate the country code accurately 
>>> given only a phone number that may or may not be complete.
>>>
>>> Rhino
>>
>>
>> Everything you say is true, if the list contains incomplete phone 
>> numbers, but why do you assume that is the case?  The OP said no such 
>> thing.  The question is, given a string such as '911122334455', how do 
>> you find rows in the country_table where the prefix column matches the 
>> beginning of the string?  I think that amounts to, how do I do string 
>> comparisons in mysql?
>>
> Actually, it is the _original poster_ that is assuming the phone number 
> is complete; I'm just trying to warn him that the problem becomes nearly 
> insoluble if the phone number _isn't_ complete.

He may not be *assuming*, he may know, but okay.

> Even if the number is complete, if we don't know the country associated 
> with the phone number, which is the whole problem, how many digits of 
> the number are the country code if the country code can be 1 thru 4 digits?

You don't need to know the number of digits to perform the requested string 
comparison.  See my earlier reply for the query.  So long as phone numbers are 
unambiguous, only one row should match.

> Rhino

Michael
Thread
Mysql Finding the country name from country prefixabhishek jain19 Nov
  • Re: Mysql Finding the country name from country prefixRhino19 Nov
    • Re: Mysql Finding the country name from country prefixMichael Stassen19 Nov
    • Re: Mysql Finding the country name from country prefixBjörn Persson19 Nov
  • Re: Mysql Finding the country name from country prefixPeter Brawley19 Nov
    • Re: Mysql Finding the country name from country prefixMichael Stassen19 Nov
  • Re: Mysql Finding the country name from country prefixMichael Stassen19 Nov
  • Re: Mysql Finding the country name from country prefixRhino19 Nov
    • Re: Mysql Finding the country name from country prefixMichael Stassen19 Nov
  • Re: Mysql Finding the country name from country prefixRhino19 Nov
    • Re: Mysql Finding the country name from country prefixMichael Stassen20 Nov
      • Re: Mysql Finding the country name from country prefixJasper Bryant-Greene20 Nov
        • Re: Mysql Finding the country name from country prefixMichael Stassen20 Nov
        • Re: Mysql Finding the country name from country prefixBjörn Persson20 Nov