libmysql.dll有64位和32位版本. 重建Qt驱动程序是不是必须的.

There are 64 bit and 32 bit versions of libmysql.dll. rebuilding the Qt Driver is NOT a must.

使用Qt5.9.1的预构建版本，您仍然需要使用32位版本，即使在64版本的MySQL安装中也可以使用.无需重建任何QT插件或组件. 在此处下载32位MySQL连接器

With the prebuilt version of Qt5.9.1, you still need to use the 32 bit version, it worked even with the 64 version of MySQL installation. without any rebuild of QT plugins or components. Download 32 bit MySQL connector here

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