@api.multi
def get_all_so(self, name=None):
    sql = "select * from sale_order where name like '%s%' order by name desc;" % name
    self.env.cr.execute(sql)
    res_all = self.env.cr.fetchall()
    #fetchall() will return an array of dictionaries
    return res_all
 
@api.multi
def get_so(self, name=None):
    sql = "select * from sale_order where name like '%s' order by name desc;" % name
    self.env.cr.execute(sql)
    #fetchone() will return the first element found as dictionary
    res_one = self.env.cr.fetchone()
    return res_one
 
print(self.get_all_so(name='SO2018'))
[{'name':'SO2018001','partner_id':'Customer 1',...},{'name':'SO2018002','partner_id':'Customer 2', ...}]
 
print(self.get_so(name='SO2018001'))
{'name':'SO2018001','partner_id':'Customer 1',...}