select * from ticketinstance as t
left outer join batch on t.Col_Batch = batch.Col_ObjId
left outer join ticket on t.Col_ObjId = ticket.Col_ObjId
where t.Col_ObjId =2 and Col_Batch = 2
正确
select * from ticketinstance as 't'
left outer join batch on t.Col_Batch = batch.Col_ObjId
left outer join ticket on t.Col_ObjId = ticket.Col_ObjId
where t.Col_ObjId =2 and Col_Batch = 2
错误