求一查询语句 感谢
表device
device_code,device_name,device_type,type_name
FH-0001, 磨床, M01, 机加工类
FH-0002, 车床, M01, 机加工类
FH-0003 钻床, M02, 机加工类
求根据device_type相同的求和统计显示为:
device_code,device_name,device_type,type_name, count
FH-0001, 磨床, M01, 机加工类, 2
FH-0002, 车床, M01, 机加工类, 2
FH-0003 钻床, M02, 机加工类, 1
我知道用group by,我想保留每行的device_code。谢谢