使用WITH（NOLOCK）的SQL Server内部联接

Question

我有一个数据库查询：

DECLARE @Pager_PageNumber AS INT, @Pager_PageSize AS INT; 

SET @Pager_PageNumber = 1; 
SET @Pager_PageSize = 12; 

SELECT 
    [Name], [Description], [Table1ID], [VersionNo], [Status] 
FROM
    (SELECT 
         CAST(Table1.name AS VARCHAR(MAX)) As [Name],
         CAST(Table1.description AS VARCHAR(MAX)) AS [Description],
         CAST(CAST(Table1.Table1_ID AS DECIMAL(18,0)) AS VARCHAR(MAX)) AS [Table1ID],
         CAST(CAST(Table1.VERSION_NO AS DECIMAL(18,0)) AS VARCHAR(MAX)) AS [VersionNo],
         CAST(Table2.br_status AS VARCHAR(MAX)) AS [Status]  
    FROM  
        Table1 WITH (NOLOCK)
    INNER JOIN 
        (SELECT 
             Table1_id, MAX(version_no) as version_no
         FROM Table1
         WHERE Table1.status = '00002'
         GROUP BY Table1_id) AS BR WITH (NOLOCK) ON Table1.Table1_id = BR.Table1_id 
                                                 AND BR.version_no = Table1.version_no 
    INNER JOIN 
        Table2 WITH (NOLOCK) ON Table1.status = Table2.br_status_code) A 
ORDER BY 
    [Name], [Description], [Table1ID], [VersionNo], [Status] 
    OFFSET ((@Pager_PageNumber - 1) * @Pager_PageSize) ROWS 
       FETCH NEXT @Pager_PageSize ROWS ONLY;

SELECT COUNT(*) 
FROM
    (SELECT 
         CAST(Table1.name AS VARCHAR(MAX)) AS [Name],
         CAST(Table1.description AS VARCHAR(MAX)) AS [Description],
         CAST(CAST(Table1.Table1_ID AS DECIMAL(18,0)) AS VARCHAR(MAX)) AS [Table1ID],
         CAST(CAST(Table1.VERSION_NO AS DECIMAL(18,0)) AS VARCHAR(MAX)) As [VersionNo],
         CAST(Table2.br_status AS VARCHAR(MAX)) AS [Status]  
    FROM  
        Table1 WITH (NOLOCK)  
    INNER JOIN
        (SELECT Table1_id, MAX(version_no) as version_no
         FROM Table1
         WHERE Table1.status = '00002'
         GROUP BY Table1_id) AS BR WITH (NOLOCK) ON Table1.Table1_id = BR.Table1_id 
                                                 AND BR.version_no = Table1.version_no 
    INNER JOIN 
        Table2 WITH (NOLOCK) ON Table1.status = Table2.br_status_code) A;

在SQL Server中，我得到附近的错误BR WITH (NOLOCK)：

关键字“ WITH”附近的语法不正确。关键字“ with”附近的语法不正确。如果此语句是公用表表达式，xmlnamespaces子句或更改跟踪上下文子句，则前一条语句必须以分号终止。

但是据我从语法这样的来源了解到

SELECT 
    first_name, last_name,
FROM 
    dbo.person p WITH (NOLOCK)
JOIN 
    dbo.employee e WITH (NOLOCK) ON e.person_id = p.person_id
WHERE 
    p.person_id = 1;

因此，我的查询看起来差不多正确。

另外，当我删除BR WITH (NOLOCK)内部联接查询旁边的WITH（NOLOCK）时，查询运行良好。关于我可能会缺少的任何想法？

PS：我的数据库兼容性级别是110。

Answer 1

您适用with (nolock)于表，而不适用于子查询。因此，代替：

(SELECT Table1_id, MAX(version_no) as version_no
 FROM Table1
 where Table1.status='00002'
 GROUP BY Table1_id
) as BR WITH (NOLOCK)

你会这样写：

(SELECT Table1_id, MAX(version_no) as version_no
 FROM Table1 WITH (NOLOCK)
 where Table1.status='00002'
 GROUP BY Table1_id
) BR

Answer 2

就放

SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED

在您查询之前。NOLOCK 行为将用于查询中的所有表。使用提示 NOLOCK 仅意味着对特定表使用 READ UNCOMMITTED 事务隔离级别。