Question

我有2个表，第一个表的字段名称具有以下结构。

CREATE TABLE [dbo].[FieldNames](
    [SiteId] [int] NULL,
    [Column_1] [nvarchar](50) NULL,
    [Column_2] [nvarchar](50) NULL,
    [Column_3] [nvarchar](50) NULL,
    [Name] [nvarchar](50) NULL
) ON [PRIMARY]

此表包含以下数据

1   FirstName   LastName    City    Coutry
2   City        Coutry      Name    Gender

我还有另一个表，其中包含具有以下结构的列值。

CREATE TABLE [dbo].[FieldValue](
    [RowId] [int] NULL,
    [SiteId] [int] NULL,
    [Column1_Value] [nvarchar](50) NULL,
    [Column2_Value] [nvarchar](50) NULL,
    [Column3_Value] [nvarchar](50) NULL,
    [Name] [nvarchar](50) NULL
) ON [PRIMARY]

此表包含以下数据。

1   1   ABC     XYZ     Ahmedaad    India
2   1   Hello   Smith   Kodiar  India
3   2   Ahmedaad    India   Happy   data

我想要类似siteid = 1的结果

**FirstName     LastName     City     Coutry**
ABC             XYZ          Ahmedaad India
Hello           Smith        Kodiar   India

Answer 1

您真的需要使用这种设计吗？它可能很灵活，但是编码，开发，调试和维护将是一场噩梦。

declare @siteid int = 1
declare @sql    nvarchar(max)

select  @sql    = 'SELECT '
        + '[Column1_Value] as ' + quotename([Column_1]) + ', '
        + '[Column2_Value] as ' + quotename([Column_2]) + ', '
        + '[Column3_Value] as ' + quotename([Column_3]) + '  ' + char(13)
        + 'FROM [FieldValue] v' + char(13)
        + 'WHERE v.[SiteId] = @siteid'
from    [FieldNames] n
where   n.SiteId    = @siteid

print   @sql
exec    sp_executesql @sql, N'@siteid int', @siteid

Answer 2

尝试一下

SELECT [FirstName],
        [LastName],
        [City],
        [Coutry]
FROM [FieldNames] n
INNER JOIN [dbo].[FieldValue] v
    ON n.[SiteId]=v.[SiteId]
CROSS APPLY ( VALUES  (   v.Column1_Value,
                          v.Column2_Value,
                          v.Column3_Value,
                          v.name)
            )
dt ([FirstName],[LastName],[City],[Coutry])
WHERE n.[SiteId]=1

结果

FirstName   LastName    City        Coutry
------------------------------------------
ABC          XYZ        Ahmedaad    India
Hello        Smith      Kodiar      India

Answer 3

我建议通过另一个SQL查询创建相应的（动态）查询，并在循环中执行这些查询（或根据需要单独执行）。以下查询将为您提供动态语句：

SELECT DISTINCT fv.[SiteId],
'SELECT     fv.RowId, ' +
'fv.SiteId, ' +
'fv.Column1_Value AS ' + fn.Column_1 + ', ' +
'fv.Column2_Value AS ' + fn.Column_2 + ', ' +
'fv.Column3_Value AS ' + fn.Column_3 + ', ' +
'fv.Name ' +
'FROM [dbo].[FieldValue] fv ' +
'WHERE fv.SiteId = ' + CAST(fv.[SiteId] AS varchar(10)) AS stmt

FROM [dbo].[FieldValue] fv
JOIN [dbo].[FieldNames] fn ON fv.SiteId = fn.SiteId

从SQL Server表的第一行获取列名

3 个答案: