如何在带有动态列的SQL中使用SUM函数

DECLARE @tbl TABLE (City VARCHAR(25), [2018-07-14] int, [2018-07-15] int, 
    [2018-07-16] int, Total AS [2018-07-14] + [2018-07-15] + [2018-07-16])

INSERT INTO @tbl VALUES ('Satara', 3, 9, 1)
INSERT INTO @tbl VALUES ('Maharashtra', 0, 4, 1)
INSERT INTO @tbl VALUES ('Ghatkopar', 10, 1, 1)

SELECT City, SUM([2018-07-14]) AS [2018-07-14], 
    SUM([2018-07-15]) AS [2018-07-15], 
    SUM([2018-07-16]) AS [2018-07-16],
    SUM(Total) AS Total
FROM @tbl
GROUP BY ROLLUP (City);

City        2018-07-14  2018-07-15  2018-07-16  Total
Ghatkopar   10          1           1           12
Maharashtra 0           4           1           5
Satara      3           9           1           13
NULL        13          14          3           30

DECLARE @D1 VARCHAR(10) = FORMAT(GETDATE() - 2, 'yyyy-MM-dd')
DECLARE @D2 VARCHAR(10) = FORMAT(GETDATE() - 1, 'yyyy-MM-dd')
DECLARE @D3 VARCHAR(10) = FORMAT(GETDATE(), 'yyyy-MM-dd')

DECLARE @SQL NVARCHAR(MAX)
SELECT @SQL = '
SELECT City, SUM([' + @D1 + ']) AS [' + @D1 + '], 
    SUM([' + @D2 + ']) AS [' + @D2 + '], 
    SUM([' + @D3 + ']) AS [' + @D3 + '],
    SUM([' + @D1 + '] + [' + @D2 + '] + [' + @D3 + ']) AS Total
FROM tbl
GROUP BY ROLLUP (City);'

EXEC sp_executesql @SQL