Exec 失败是因为名称不是有效的标识符吗？

我有一个查询，我需要运行它作为一个动态查询输出一个有意义的列名称。例如，如果直接运行查询，它将正确返回数据。但是，如果我使用下面的代码，它会显示:

The name '
SELECT (CASE WHEN A.Domain IS NOT NULL THEN A.Domain ELSE B.Domain END) AS [Domain],
(CASE WHEN A.Email IS NOT NULL THEN A.Email ELSE B.Email END) AS [Email],
A.[Sender Size] AS [Sender Size 1], A.[Sender Count] AS [Sender Count 1],
A.[Receiver Size] AS [Receiver Size 1], A.[Receiver Count] AS [Receiver Count 1],
A.[Sender Size 2] AS [Sender Size 2], A.[Sender Count 2] AS [Sender Count 2],
A.[Receiver Size 2] AS [Receiver Size 2], A.[Receiver Count 2] AS [Receiver Count 2],
B.SenderSize AS [Sender Size Average], B.SenderCount AS [Sender Count Average],
B.ReceiverSize AS [Receiv' is not a valid identifier.

下面是密码:

DECLARE @query NVARCHAR(4000)
SET @query = N'SELECT *
FROM
(
SELECT (CASE WHEN A.Domain IS NOT NULL THEN A.Domain ELSE B.Domain END) AS [Domain],
(CASE WHEN A.Email IS NOT NULL THEN A.Email ELSE B.Email END) AS [Email],
A.[Sender Size] AS [Sender Size 1], A.[Sender Count] AS [Sender Count 1],
A.[Receiver Size] AS [Receiver Size 1], A.[Receiver Count] AS [Receiver Count 1],
A.[Sender Size 2] AS [Sender Size 2], A.[Sender Count 2] AS [Sender Count 2],
A.[Receiver Size 2] AS [Receiver Size 2], A.[Receiver Count 2] AS [Receiver Count 2],
B.SenderSize AS [Sender Size Average], B.SenderCount AS [Sender Count Average],
B.ReceiverSize AS [Receiver Size Average], B.ReceiverCount AS [Receiver Count Average]
FROM
(
SELECT (CASE WHEN tf.Domain IS NOT NULL THEN tf.Domain ELSE tf2.Domain END) AS Domain,
(CASE WHEN tf.Email IS NOT NULL THEN tf.Email ELSE tf2.Email END) AS Email,
ISNULL(tf.SenderSize,0) AS [Sender Size] , ISNULL(tf.SenderCount,0) AS [Sender Count], ISNULL(tf.ReceiverSize,0) AS [Receiver Size], ISNULL(tf.ReceiverCount,0) AS [Receiver Count],
ISNULL(tf2.SenderSize,0) AS [Sender Size 2], ISNULL(tf2.SenderCount,0) AS [Sender Count 2], ISNULL(tf2.ReceiverSize,0) AS [Receiver Size 2], ISNULL(tf2.ReceiverCount,0) AS [Receiver Count 2]
FROM #TrafficFinal tf FULL JOIN #TrafficFinal2 tf2 ON (tf.Email = tf2.Email AND tf.Domain = tf2.Domain)
) A FULL JOIN #TrafficFinal3 B ON (A.Email = B.Email AND A.Domain = B.Domain)
) C
ORDER BY Domain, Email';


PRINT @query;


-- run it
exec @query;

是因为全连接吗？