delimiting data in a mysql database without exporting it
url.com?some=0
url2.com?some=14

UPDATE tablename SET url = SUBSTRING_INDEX(url, "?", 1);

mysql> select url, case when locate('?', url) = 0 then url else substring(url, 1, locate('?', url) - 1) end as truncated from urls;
+------------------+-----------+
| url              | truncated |
+------------------+-----------+
| url.com?some=0   | url.com   |
| url2.com?some=14 | url2.com  |
| url3.com         | url3.com  |
+------------------+-----------+

update your_table
set url = case when locate('?', url) = 0 then url else substring(url, 1, locate('?', url) - 1) end

mysql> select url, substring_index(url, '?', 1) from urls;
+------------------+------------------------------+
| url              | substring_index(url, '?', 1) |
+------------------+------------------------------+
| url3.com         | url3.com                     |
| url.com?some=0   | url.com                      |
| url2.com?some=14 | url2.com                     |
+------------------+------------------------------+

update your_table
set url = substring_index(url, '?', 1)