Question

我很难解释这个问题，但也许一个例子有帮助...

我有两张桌子，a和b

a是一个空表，它有三列：

id   name  value

b是一个表，对于a和其他一些列具有相同的id，如下所示：

id    obj_type       obj_status        language
-------------------------------------------------
1     product        operational       English
2     support        operational       French
3     product        non_operational   English

现在我想以这种方式将表b中的数据插入到a：

id    name           value
--------------------------------------
1     obj_type       product
1     obj_status     operational     
1     language       English
2     obj_type       support 
2     obj_status     operational                                         
2     language       French
3     obj_type       product                    
3     obj_status     non_operational                               
3     language       English

我想知道Postgres是否有办法做到这一点

Answer 1

应该有效

INSERT INTO TableA
SELECT id,'obj_type' as Name, obj_type as Value FROM TableB UNION
SELECT id,'obj_status' as Name,obj_status as Value FROM TableB UNION
SELECT id,'languagee' as Name,  language as Value FROM TableB
ORDER BY id

Answer 2

SELECT id,
(SELECT Column_name FROM Information_schema.columns 
WHERE Table_name ='tableB' AND ORDINAL_POSITION = 2) as Name, obj_type as Value FROM tableB UNION
SELECT id,
(SELECT Column_name FROM Information_schema.columns WHERE Table_name ='tableB' AND ORDINAL_POSITION = 3) as Name,obj_status as Value FROM tableB UNION
SELECT id,
(SELECT Column_name FROM Information_schema.columns WHERE Table_name ='tableB' AND ORDINAL_POSITION = 4) as Name,  _language as Value FROM tableB
ORDER BY id,Name

使用唯一映射将数据从一个移动到另一个

2 个答案: