在SQL Server中选择列名作为另一个表行数据

Question

我有一张表Configs，其中我有列名

id  | Name
-------------
1   | Fruits
2   | Vegetables
3   | Pulses

我有另一张桌子说Details

id  |Field1 | Field2| Field3   | Active | Mandatory
-------------------------------------------------
1   |Apple  |Potato |Red gram  |  1     |0
2   |Mango  |Peas   |Chick Peas|  0     |0

我需要选择field1，field2，field3作为第一个表的名称 例如

select 
    id,
    Field1 as Fruits,
    Field2 as Vegetables,
    Field3 as pulses,
    Active,
    Mandatory 
From  
    Details

我该怎么做？

Answer 1

declare @sql    nvarchar(max)

select  @sql    = isnull(@sql + ',' ,'')
        + N'Field' + convert(varchar(10), id) + ' as ' + quotename(Name)
from    Config

-- Form the dynamic SQL
select  @sql    = 'SELECT id,'
        + @sql
        + ',Active, Mandatory '
        + 'FROM Details'

-- Print to verify
print   @sql

-- Execute it
exec    sp_executesql @sql 

Answer 2

或许这样的事情：

方法＃1

IF OBJECT_ID(N'Configs', N'U') IS NULL
    CREATE TABLE Configs(ID INT, Name NVARCHAR(25));
ELSE
    TRUNCATE TABLE Configs

INSERT INTO Configs VALUES(1, 'Fruits'), (2, 'Vegetables'), (3, 'Pulses');

IF OBJECT_ID(N'Configs', N'U') IS NULL
    CREATE TABLE Details(ID INT, Field1 NVARCHAR(25), Field2 NVARCHAR(25), Field3 NVARCHAR(25)
                        ,Active BIT, Mandatory BIT);
ELSE
    TRUNCATE TABLE Details

INSERT INTO Details VALUES(1, 'Apples', 'Potato', 'Red Gram', 1, 0)
                            ,(2, 'Mango', 'Peas', 'Chick Peas', 0, 0);

DECLARE @Sql NVARCHAR(MAX);
SELECT @Sql = 'SELECT id,' + CHAR(13)
            + ' [Field1] as ' + QUOTENAME((SELECT Name FROM Configs WHERE ID = 1)) +',' + CHAR(13)
            + ' [Field2] as ' + QUOTENAME((SELECT Name FROM Configs WHERE ID = 2)) +',' + CHAR(13)
            + ' [Field3] as ' + QUOTENAME((SELECT Name FROM Configs WHERE ID = 3)) +',' + CHAR(13)
                + ' Active,' + CHAR(13)
                + ' Mandatory ' + CHAR(13)
                + 'From  Details' + CHAR(13);

PRINT @Sql;
EXEC sp_executesql @Sql;

方法＃2

IF OBJECT_ID(N'Configs', N'U') IS NULL
    CREATE TABLE Configs(ID INT, Name NVARCHAR(25));
ELSE
    TRUNCATE TABLE Configs

INSERT INTO Configs VALUES(1, 'Fruits'), (2, 'Vegetables'), (3, 'Pulses');

IF OBJECT_ID(N'Configs', N'U') IS NULL
    CREATE TABLE Details(ID INT, Field1 NVARCHAR(25), Field2 NVARCHAR(25), Field3 NVARCHAR(25)
                        ,Active BIT, Mandatory BIT);
ELSE
    TRUNCATE TABLE Details

INSERT INTO Details VALUES(1, 'Apples', 'Potato', 'Red Gram', 1, 0)
                            ,(2, 'Mango', 'Peas', 'Chick Peas', 0, 0);

DECLARE @Sql NVARCHAR(MAX) = 'SELECT' + CHAR(13) + CHAR(9) + 'ID' + CHAR(13);

SELECT
    @Sql += STUFF((
                    SELECT
                        CHAR(9) + ',' + QUOTENAME('Field' + LTRIM(STR(ROW_NUMBER()OVER(ORDER BY ID)))) + ' AS ' + QUOTENAME(Name) + CHAR(13)
                    FROM
                        Configs
        FOR XML PATH(''), type).value('.', 'nvarchar(max)'), 1, 0, '');

SELECT
    @Sql += CHAR(9) +',Active' + CHAR(13)
            + CHAR(9) +',Mandatory ' + CHAR(13)
            + 'From  Details' + CHAR(13);

PRINT @Sql;
EXEC sp_executesql @Sql;