gistfile1.sql

-- mysql has an default escape character \                                      
SELECT * FROM people WHERE symbol LIKE 'hello\_world';
-- or you can specify the escape character                                      
SELECT * FROM people WHERE symbol LIKE 'hello|_world' ESCAPE '|';

-- tsql has no default but you can go with a single character class             
SELECT * FROM people WHERE symbol LIKE 'hello[_]world';
-- or you can specify an escape character                                       
SELECT * FROM people WHERE symbol LIKE 'hello|_world' ESCAPE '|';