Question

我的Postgres查询有问题。

我有3张桌子：

1) Carrier
  *id
  *name
  *telephone
  *address
  *comments


2) Transportlist
   *id
   *name

3) Carrier_transport
   *id
   *carrier_id
   *transport_list_id

例如：

Carrier:           Transportlist:      Carrier_transport:
ID | name          ID  |  name         ID | carrier_id  | transport_list_id
 1 | ABC            1  | Car            1 |     1                1
 2 | XYZ            2  | Tir            2 |     1                2
 3 | 111            3  | Plane          3 |     1                3
                    4  | ferry          4 |     2                1
                                        5 |     3                4
                                        6 |     3                3
                                        7 |     3                2

我必须只选择有传输列表Car AND Tir

的运营商

我试过了：

Select  FROM Carrier c 
LEFT JOIN Carrier_transport ct ON (ct.carrier_id = c.id)
WHERE ct.transport_list_id IN (1,2) 
GROUP BY c.id
HAVING COUNT(*)>=2

但这种解决方案是错误的。

有人可以帮助我吗？

Answer 1

select ct.carrier_id
from
    transportlist tl 
    inner join
    carrier_transport ct on ct.transport_list_id = tl.id
where ct.transport_list_id in (1,2) 
group by 1
having bool_or(tl.id = 1) and bool_or(tl.id = 2)

Aggregate functions

Postgres查询WHERE数组

1 个答案: