The maximum length of the string you can enter in the Audience Key field of a reporting schema is 255 characters. If the audience key is longer than 255 characters, you can work around this restriction in the generated SQL. Enter the first 255 characters of the key in the
Audience Key field and generate the SQL script as usual. Then, open the generated script in an editor and use find and replace to replace each of the truncated audience key references with the complete string.