delete MySQL

delete from rqgl_p a  where a.rqgl_name='3号燃气锅炉';   //这样用别名不对

delete a from rqgl_p a  where a.rqgl_name='3号燃气锅炉'; 

delete a from rqgl_p a
where a.RQGL_NAME in (select b.RQGL_NAME from rqgl_info b where b.RQGL_ID='3');

delete a from rqgl_p a
where exists (select * from rqgl_info b where b.RQGL_ID='3' and a.RQGL_NAME=b.RQGL_NAME);

//multiyDelete

delete rqgl_p                 //这样写不对，rqgl_p应该包含在from中，如下一条
from rqgl_info,glf_info
where rqgl_p.RQGL_NAME=rqgl_info.RQGL_NAME and glf_info.GLF_ID=13 and rqgl_info.GLF_ID=glf_info.GLF_ID;

delete rqgl_p
from rqgl_p,rqgl_info,glf_info
where rqgl_p.RQGL_NAME=rqgl_info.RQGL_NAME and glf_info.GLF_ID=13 and rqgl_info.GLF_ID=glf_info.GLF_ID;