按SQL Server中的varbinary（MAX）或varchar（MAX）

Question

在SQL Server 2008 R2联机丛书中，它意味着分组列的最大列大小为8060字节。

“对于GROUP BY不包含CUBE或ROLLUP子句的group_by_expression项目的数目时由GROUP LIMITED由列的大小，聚合列和查询中涉及的合计值。此限制源自于保留中间查询结果所需的中间工作表上的8,060字节的限制。“

但是你可以组由VARBINARY（max）列：

create table dbo.T(
    name varchar(100), 
    info varbinary(max) 
); 
insert into dbo.T values ('aardvark', Convert(varbinary(max),Replicate(Convert(varchar(max),'A'),100000))) 
select info, count(*) from T group by info; 

上述工程在SQL Server 2008 R2的罚款，并可能更高版本。我误读了联机丛书吗？有谁知道是否允许按大对象类型进行分组？我也搜索了这个没有结果。

Answer 1

由于固定宽度数据类型始终存储在行中，因此您更有可能遇到此问题。可变长度类型可以通过指向实际值的指针存储在行外。

CREATE TABLE #T 
    (
    C CHAR(4027) DEFAULT REPLICATE('A', 4027) 
); 

INSERT INTO #T 
DEFAULT VALUES; 

SELECT COUNT(*) 
FROM #T T1 
     CROSS JOIN #T T2 
GROUP BY T1.C, 
      T2.C 

因为工作台 是必需的查询处理器未能生成查询计划，其最小的行大小超过 8060字节的最大允许。为什么要求工作表的典型原因是GROUP BY 或查询中的ORDER BY子句。如果查询具有GROUP BY或ORDER BY子句，请考虑减少该子句中 字段的数量和/或大小。考虑使用 字段的前缀（LEFT（））或散列（CHECKSUM（））作为排序的分组或前缀。但请注意，此 将更改查询的行为。

但是，下面的成功。

SELECT COUNT(*) 
FROM #T T1 
     CROSS JOIN #T T2 
GROUP BY CAST(T1.C AS VARCHAR(4027)), 
      CAST(T2.C AS VARCHAR(4027)) 

您可以按高达308 VARCHAR（最大）列 - 与每列仅包括26个字节存储在行（pointer to the value and other overhead）。下面

失败

不能创建大小8078的一排这比8060

允许的 最大行尺寸更大，但去掉GROUP BY列的任何，它会成功为8078-26小于8060.

注意：每个单独列的值都会消耗10,000个字节，但这些值存储在行外并与上述计算无关。

drop TABLE #T 

GO 

CREATE TABLE #T 
(
C0 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C1 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C2 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C3 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C4 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C5 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C6 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C7 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C8 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C9 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C10 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C11 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C12 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C13 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C14 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C15 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C16 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C17 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C18 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C19 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C20 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C21 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C22 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C23 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C24 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C25 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C26 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C27 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C28 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C29 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C30 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C31 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C32 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C33 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C34 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C35 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C36 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C37 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C38 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C39 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C40 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C41 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C42 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C43 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C44 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C45 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C46 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C47 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C48 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C49 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C50 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C51 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C52 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C53 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C54 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C55 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C56 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C57 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C58 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C59 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C60 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C61 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C62 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C63 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C64 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C65 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C66 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C67 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C68 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C69 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C70 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C71 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C72 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C73 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C74 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C75 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C76 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C77 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C78 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C79 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C80 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C81 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C82 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C83 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C84 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C85 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C86 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C87 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C88 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C89 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C90 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C91 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C92 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C93 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C94 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C95 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C96 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C97 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C98 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
,C99 VARCHAR(MAX) DEFAULT REPLICATE(CAST('X' AS VARCHAR(MAX)),10000) 
) 


INSERT INTO #T DEFAULT VALUES 


SELECT COUNT(*) 
FROM #T T1, 
    #T T2, 
    #T T3, 
    #T T4 
GROUP BY 
T1.C0 
,T1.C1 
,T1.C2 
,T1.C3 
,T1.C4 
,T1.C5 
,T1.C6 
,T1.C7 
,T1.C8 
,T1.C9 
,T1.C10 
,T1.C11 
,T1.C12 
,T1.C13 
,T1.C14 
,T1.C15 
,T1.C16 
,T1.C17 
,T1.C18 
,T1.C19 
,T1.C20 
,T1.C21 
,T1.C22 
,T1.C23 
,T1.C24 
,T1.C25 
,T1.C26 
,T1.C27 
,T1.C28 
,T1.C29 
,T1.C30 
,T1.C31 
,T1.C32 
,T1.C33 
,T1.C34 
,T1.C35 
,T1.C36 
,T1.C37 
,T1.C38 
,T1.C39 
,T1.C40 
,T1.C41 
,T1.C42 
,T1.C43 
,T1.C44 
,T1.C45 
,T1.C46 
,T1.C47 
,T1.C48 
,T1.C49 
,T1.C50 
,T1.C51 
,T1.C52 
,T1.C53 
,T1.C54 
,T1.C55 
,T1.C56 
,T1.C57 
,T1.C58 
,T1.C59 
,T1.C60 
,T1.C61 
,T1.C62 
,T1.C63 
,T1.C64 
,T1.C65 
,T1.C66 
,T1.C67 
,T1.C68 
,T1.C69 
,T1.C70 
,T1.C71 
,T1.C72 
,T1.C73 
,T1.C74 
,T1.C75 
,T1.C76 
,T1.C77 
,T1.C78 
,T1.C79 
,T1.C80 
,T1.C81 
,T1.C82 
,T1.C83 
,T1.C84 
,T1.C85 
,T1.C86 
,T1.C87 
,T1.C88 
,T1.C89 
,T1.C90 
,T1.C91 
,T1.C92 
,T1.C93 
,T1.C94 
,T1.C95 
,T1.C96 
,T1.C97 
,T1.C98 
,T1.C99 

,T2.C0 
,T2.C1 
,T2.C2 
,T2.C3 
,T2.C4 
,T2.C5 
,T2.C6 
,T2.C7 
,T2.C8 
,T2.C9 
,T2.C10 
,T2.C11 
,T2.C12 
,T2.C13 
,T2.C14 
,T2.C15 
,T2.C16 
,T2.C17 
,T2.C18 
,T2.C19 
,T2.C20 
,T2.C21 
,T2.C22 
,T2.C23 
,T2.C24 
,T2.C25 
,T2.C26 
,T2.C27 
,T2.C28 
,T2.C29 
,T2.C30 
,T2.C31 
,T2.C32 
,T2.C33 
,T2.C34 
,T2.C35 
,T2.C36 
,T2.C37 
,T2.C38 
,T2.C39 
,T2.C40 
,T2.C41 
,T2.C42 
,T2.C43 
,T2.C44 
,T2.C45 
,T2.C46 
,T2.C47 
,T2.C48 
,T2.C49 
,T2.C50 
,T2.C51 
,T2.C52 
,T2.C53 
,T2.C54 
,T2.C55 
,T2.C56 
,T2.C57 
,T2.C58 
,T2.C59 
,T2.C60 
,T2.C61 
,T2.C62 
,T2.C63 
,T2.C64 
,T2.C65 
,T2.C66 
,T2.C67 
,T2.C68 
,T2.C69 
,T2.C70 
,T2.C71 
,T2.C72 
,T2.C73 
,T2.C74 
,T2.C75 
,T2.C76 
,T2.C77 
,T2.C78 
,T2.C79 
,T2.C80 
,T2.C81 
,T2.C82 
,T2.C83 
,T2.C84 
,T2.C85 
,T2.C86 
,T2.C87 
,T2.C88 
,T2.C89 
,T2.C90 
,T2.C91 
,T2.C92 
,T2.C93 
,T2.C94 
,T2.C95 
,T2.C96 
,T2.C97 
,T2.C98 
,T2.C99 


,T3.C0 
,T3.C1 
,T3.C2 
,T3.C3 
,T3.C4 
,T3.C5 
,T3.C6 
,T3.C7 
,T3.C8 
,T3.C9 
,T3.C10 
,T3.C11 
,T3.C12 
,T3.C13 
,T3.C14 
,T3.C15 
,T3.C16 
,T3.C17 
,T3.C18 
,T3.C19 
,T3.C20 
,T3.C21 
,T3.C22 
,T3.C23 
,T3.C24 
,T3.C25 
,T3.C26 
,T3.C27 
,T3.C28 
,T3.C29 
,T3.C30 
,T3.C31 
,T3.C32 
,T3.C33 
,T3.C34 
,T3.C35 
,T3.C36 
,T3.C37 
,T3.C38 
,T3.C39 
,T3.C40 
,T3.C41 
,T3.C42 
,T3.C43 
,T3.C44 
,T3.C45 
,T3.C46 
,T3.C47 
,T3.C48 
,T3.C49 
,T3.C50 
,T3.C51 
,T3.C52 
,T3.C53 
,T3.C54 
,T3.C55 
,T3.C56 
,T3.C57 
,T3.C58 
,T3.C59 
,T3.C60 
,T3.C61 
,T3.C62 
,T3.C63 
,T3.C64 
,T3.C65 
,T3.C66 
,T3.C67 
,T3.C68 
,T3.C69 
,T3.C70 
,T3.C71 
,T3.C72 
,T3.C73 
,T3.C74 
,T3.C75 
,T3.C76 
,T3.C77 
,T3.C78 
,T3.C79 
,T3.C80 
,T3.C81 
,T3.C82 
,T3.C83 
,T3.C84 
,T3.C85 
,T3.C86 
,T3.C87 
,T3.C88 
,T3.C89 
,T3.C90 
,T3.C91 
,T3.C92 
,T3.C93 
,T3.C94 
,T3.C95 
,T3.C96 
,T3.C97 
,T3.C98 
,T3.C99 
,T4.C0 
,T4.C1 
,T4.C2 
,T4.C3 
,T4.C4 
,T4.C5 
,T4.C6 
,T4.C7 
,T4.C8