Dynamic Column Names from one table and its corresponding values from another table

Question

I have 2 tables. First tables gives the specification if a column is required or not. we have the 2nd table with the same column name where we provide the actual values.
I want to select all the required columns from the 1st table and retrieve the values for those from the 2nd table. Both this i want to achieve in a single select statement.

Answer 1

This wil require a dynamic Query with a Pivot
DECLARE @ColsPivot as VARCHAR(MAX);
DECLARE @Query  AS VARCHAR(MAX);
1. Retreive the ID for all required field
SET @ColsPivot = (SELECT STUFF((SELECT  ',' + quotename(CAST([RequirementID] as varchar(3))) FROM [dbo].[Requirement] WHERE required=1 FOR XML PATH(''), TYPE).value('.', 'NVARCHAR(MAX)') ,1,1,''));
This will give you : [1],[2],[3],[8],[9],[14] for exemple.
2. Build your Query
SET @Query ='SELECT ClientID,'+@ColsPivot+''
    FROM (
        SELECT [ClientID],[RequirementID],[Value]
        FROM dbo.RequirementValue
        WHERE ClientID=@CliendID --Optional SP parameter
    )src
          PIVOT(
            MAX(Value)
            for [RequirementID] in ('+@ColsPivot+')
    ) p';
3. Exec(@Query);