How to match part of rows in different tables with each other in MySQL?

Question

I have a table called 'urls' which contains domain name of different countries like below:

Domain
Paypal.com
wellsfargo.co.uk
sparkasse.fe.de

etc...

and I have another table called 'country' which contains tlds and their associated country like below:

tld        country
nl          netherlands
de          germany
uk          united kingdom
etc...

I do not know how can I create a match in which I would be able to extract the name of the country in the table 'country' from domains in table 'urls'.Can anyone help me with this?

Answer 1

Join the two tables with the following JOIN condition:

ON ( country.tld = RIGHT(urls.domain, CHAR_LENGTH(tld)) )

Notice this query couldn't use an index on urls.domain , if such an index exists. I would precompute the top-level domain of urls.domain on insertion in a separate column (in urls ). Set an index on this new column, and use this column in your JOIN condition.