SQL - Dynamically unpivot data

 ----------dynamically unpivot production 
DECLARE @colsUnpivot AS NVARCHAR(MAX), @query AS NVARCHAR(MAX)

USE [XXXXXX];
with tbl_metric_date_name as(
SELECT      distinct '['+ c.name+ ']' AS 'ColumnName'
FROM        sys.columns c  JOIN sys.tables  t ON c.object_id = t.object_id
WHERE       t.name ='OH_Oil_Output$' and c.name <> 'API'
)

SELECT distinct @colsUnpivot = STUFF((
SELECT ',' + ColumnName
FROM tbl_metric_date_name
FOR XML PATH ('')
                    ), 1, 1, '')
FROM tbl_metric_date_name;

set @query =
 'IF OBJECT_ID(''dbo.temp_OH_Oil_Prod'',''U'') IS NOT NULL DROP TABLE dbo.temp_OH_Oil_Prod
  SELECT API, cast(metric_date as date) as metric_date, [value]
  INTO dbo.temp_OH_Oil_Prod
  FROM [XXXXXX].[dbo].[OH_Oil_Output$] WITH(NOLOCK)
  Unpivot
  ([value] FOR metric_date in ( ' + @colsUnpivot + '))u' 

exec sp_executesql @query;