列在sql server中的行？

Question

表：

CREATE TABLE Table1 (
    col1 INT, 
    col2 nvarchar(10), 
    col3 INT, 
    col4 INT 
); 

INSERT INTO Table1 
    (col1, col2, col3, col4) 
VALUES 
    (1, 'welcome', 3, 4); 

我的表有不同的數據類型，COL2類型爲nvarchar H I可以做到這一點...

結果：

col value 
--------------- 
col1 1 
col2 welcome 
col3 3 
col4 4 

Answer 1

可以使用UNPIVOT操作，讓您的結果

SELECT col, value 
FROM 
    (SELECT CAST(col1 AS VARCHAR) AS col1, CAST(col2 AS VARCHAR) AS col2, 
     CAST(col3 AS VARCHAR) AS col3, CAST(col4 AS VARCHAR) AS col4 
    FROM Table1) p 
UNPIVOT 
    (value FOR col IN 
     (col1, col2, col3, col4) 
) AS unpvt; 

Answer 2

用途：

SELECT 'col1' AS col, 
     CAST(t1.col1 AS NVARCHAR(10)) AS value 
    FROM TABLE_1 t1 
UNION ALL 
SELECT 'col2' AS col, 
     t2.col2 AS value 
    FROM TABLE_1 t2 
UNION ALL 
SELECT 'col3' AS col, 
     CAST(t3.col3 AS NVARCHAR(10)) AS value 
    FROM TABLE_1 t3 
UNION ALL 
SELECT 'col4' AS col, 
     CAST(t4.col4 AS NVARCHAR(10)) AS value 
    FROM TABLE_1 t4 

部分問題是您需要將第二列的數據類型設置爲相同：

• CAST/CONVERT

Answer 3

with rows(n) 
as 
(
    select 1 
    union all 
    select n + 1 
    from rows 
    where n + 1 <= 4 
) 
    select case n 
      when 1 then 'col1' 
      when 2 then 'col2' 
      when 3 then 'col3' 
      when 4 then 'col4' 
      end as col, 
      case n 
      when 1 then col1 
      when 2 then col2 
      when 3 then col3 
      when 4 then col4 
      end as value 
    from 
(
    select cast (col1 as varchar) col1, 
     col2, 
     cast (col3 as varchar) col3, 
     cast (col4 as varchar) col4, 
     n 
    from table1, rows 
) x