SQL Server 2008 VarChar（Max）只返回8000个字符。为什么？

Question

PRINT Convert(VarChar(Max),Replicate('1234567890 ',1000)) 

返回窗口7,997个字符。

SELECT Convert(VarChar(Max),Replicate('1234567890 ',1000)) 

这将返回到网格7,996个字符。打印窗口中的额外字符是CRLF。我有我的选择： 工具→选项→查询结果→结果到文本→每列中显示的最大字符数= 8192

所以，我希望网格中返回8,192个字符，预计将有11,001个字符返回到我的窗口。

再就是这个测试：

DECLARE @VarCharMax VarChar(Max) 
SET @VarCharMax = Replicate('123456',2000) 
SELECT Right(@VarCharMax,3) -- returns 456 
SELECT Right(Left(@VarCharMax,8000),3) -- returns 456 
SELECT Right(Left(@VarCharMax,7999),3) -- returns 456 
SELECT Right(Left(@VarCharMax,7998),3) -- returns 456 
SELECT Right(Left(@VarCharMax,7997),3) -- returns 345 
SELECT Right(Left(@VarCharMax,7996),3) -- returns 234 

什么我在这里认识失踪？它似乎并不像我所期望的那样行事？

Answer 1

8000个字符是复制功能的限制，除非参数的类型为varchar（最大）/为nvarchar（最大）

https://msdn.microsoft.com/en-us/library/ms174383.aspx

的如果string_expression不是类型为varchar（最大值）或nvarchar（max），REPLICATE截断8,000字节的返回值。要返回大于8,000字节的值，必须将string_expression明确地转换为适当的大值数据类型。复制函数内部

Answer 2

SELECT len(Replicate(cast('1234567890' as varchar(max)),1000)) 

Returns 10000 

Answer 3

你的 '123456' 的文字是不是为varchar（max）数据类型。由于Dudu提到复制函数作为8000字符的限制，如果表达式不是varchar（max）数据类型。

Answer 4

杜杜解释清楚。字符串下面是9,060个字符。

DECLARE @VarCharMax VarChar(Max) 
SET @VarCharMax = 'This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!This is a test!' 
PRINT Right(@VarCharMax,3) -- returns st! 
PRINT Right(Left(@VarCharMax,8000),3) -- returns is 
PRINT Right(Left(@VarCharMax,7999),3) -- returns his 
PRINT Right(Left(@VarCharMax,7998),3) -- returns Thi 
PRINT Right(Left(@VarCharMax,7997),3) -- returns !Th 
PRINT Right(Left(@VarCharMax,7996),3) -- returns t!h 

这将返回我所期望的。