I have a url http://example.com/?q1=abc;q2=123;q3=xyz
When I try to add a link to this url on a SharePoint page the semicolon is replaced by
What can I do to add the correct link?
If the encoding of semicolons is breaking your query string, use ampersands instead. They are both allowed.
This is normal encoding and is required to use URLs reliably.
Look at http://www.asciitable.com to see how other characters may be encoded.