CANIOT网关通过4G网关给CAN车载控制器升级程序
CAN总线的优势 CAN(Controller Area Network)为控制器局域网络,CAN总线规范已经被国际标准化组织制订为国际标准ISO11898,并得到众多半导体器件厂商的支持,推出各种集成有CAN协议的产品。CAN属…
一. 写法: 1.左连接: SELECT student.Sno,Sname,Ssex,Sbirth,Sclass,Cno,Grade FROM student LEFT OUTER JOIN sc ON student.Snosc.Sno; 2.右连接: SELECT student.Sno,Sname,Ssex,Sbirth,Sclass,Cno,Grade FROM sc RIGHT OUTER JOIN student ON student.Snosc…