i'm trying to connect ruby2.4 to mysql, but i get a error like this :
Failed to load libmysql.dll from D:\rubyinstaller\lib\ruby\gems\1.9.1\gems\mysql2-0.4.9-x64-mingw32\vendor\libmysql.dll
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the problem is libmysql.dll.. so you must change libmysql.dll with other (by download mysql connector 6.0.x)
see this video for details :)