When I run a program which does something with MySQL, I got this error message:
2015-06-10 15:41:12,250 ERROR app.wsutils 419 INCRON: Error: (\'HY000\
In my case (MySQL version 5.6) the issue was that I was trying to create a table with a column that can have up to 256 characters (the db uses utf8 collation), so 3 bytes per 1 utf8 character = 256*3=768 bytes. The fix was to simply have 255 characters instead of 256.
I could also set innodb_large_prefix, like others suggest, but in my case it was easier to just have fewer symbols.