Php PostgreSQL中的转置查询

我有下表：

tb_item
id_item | item_name | price
----------------------------
1       | item1     | 2000
2       | item2     | 3000
3       | item3     | 4000

及

我希望得到如下输出：

item_name | price | bedroom | bathroom
---------------------------------------
item1     | 2000  | 2       | 1
item2     | 3000  | 3       | 1
item3     | 4000  | 4       | 2

我正在使用PostgreSQL；可以使用什么查询来获取此输出？

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我也在使用PHP；有一个PHP函数可以做到这一点吗？

您也可以通过几个

左JOIN

语句来实现这一点

select item_name, price, bedroom.value as bedroom, bathroom.value as bathroom
from tb_item, tb_value as bedroom, tb_value as bathroom
where bedroom.id_item=tb_item.id_item and bedroom.value_type='bedroom'
and bathroom.id_item=tb_item.id_item and bathroom.value_type='bathroom'

SELECT i.item_name
   , i.price
   , bed.value AS bedroom
   , bath.value AS bathroom
FROM tb_item AS i
LEFT JOIN tb_value AS bed ON i.id_item = bed.id_item
   AND bed.value_type = 'bedroom'
LEFT JOIN tb_value AS bath ON i.id_item = bath.id_item
   AND bath.value_type = 'bathroom'

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@JonathanLeffler，我能直接使用这些功能吗？或者之前需要安装？@FrankBollack，不，这是我工作的一部分，.+1用于将

JOIN

条件与

WHERE

过滤条件分离。@a.H.是的，抱歉。我已经更新了，谢谢你的关注。非常感谢，我想投票支持你的答案，但我还不能这么做，：DThanks@Praditha如果答案对你有帮助，你也可以点击我答案旁边的复选标记来接受。

SELECT i.item_name
   , i.price
   , bed.value AS bedroom
   , bath.value AS bathroom
FROM tb_item AS i
LEFT JOIN tb_value AS bed ON i.id_item = bed.id_item
   AND bed.value_type = 'bedroom'
LEFT JOIN tb_value AS bath ON i.id_item = bath.id_item
   AND bath.value_type = 'bathroom'