SQL - 將一行轉置爲兩列

Question

我的SQL查詢返回幾列但只返回一行。我需要將這一行和列的名稱轉換爲兩列 - 首先是列名，第二列是行值。由於某些原因，我無法使用交叉表。

我想要執行的操作如下所示。 前：

Column1 | Column2 | Column3 | Column4 
---------+---------+---------+-------- 
Value1 | Value2 | Value3 | Value4 

而且我要得到這個：

Cols | Vals 
--------+--------- 
Column1 | Value1 
Column2 | Value2 
Column3 | Value3 
Column4 | Value4 

Answer 1

select 'Column1' as Cols, Column1 as Vals from YourTable 
union all 
select 'Column2', Column2 from YourTable 
union all 
select 'Column3', Column3 from YourTable 
union all 
select 'Column4', Column4 from YourTable 

Answer 2

這是否你想要做什麼？

SELECT 
    'Column1' AS Cols 
    , Column1 AS Vals 
FROM Table 
UNION ALL 
SELECT 
    'Column2' AS Cols 
    , Column2 AS Vals 
FROM Table 
UNION ALL 
SELECT 
    'Column3' AS Cols 
    , Column3 AS Vals 
FROM Table 
UNION ALL 
SELECT 
    'Column4' AS Cols 
    , Column4 AS Vals 
FROM Table 

Answer 3

從tablefunc擴展中嘗試交叉表。 http://www.postgresql.org/docs/9.0/static/tablefunc.html

它應該做你想要的。

您可以安裝該擴展是這樣的：

CREATE EXTENSION tablefunc;