Thinkphp跨库连表查询

db1 数据库1
db2 数据库2
table1 数据表1
table2 数据表2

$spell = $this->SpellApply  ->table('db1.table1 t1,db2.table2 t2')
                            ->field('t1.uid,t2.avatar_img')
                            ->where('t1.uid=t2.uid and t1.spell_id ='.$id)
                            ->order('t1.create_time desc')
                            ->group('t1.uid')
                            ->select();