Sql Server：EXECUTE SP_EXECUTESQL 中的多个 CTE

Question

    DECLARE @sqlString nvarchar(500); SET @sqlString = ';WITH Data_CTE 
        AS
        (
            SELECT pj.ProjectID, pj.ProjectName, pj.ProjectOwner, cs.CustomerName
            FROM Projects as pj
            LEFT OUTER JOIN [Customers] cs
                ON pj.CustomerId = cs.CustomerID
            WHERE  pj.ProjectOwner =  @ename 
                AND (pj.ProjectStatus = 1 OR pj.ProjectStatus = 0)
        )
        SELECT *, (SELECT COUNT(*) FROM Data_CTE)  AS TotalRows
        FROM Data_CTE
        ORDER BY ProjectName
        OFFSET 0 * 10 ROWS
        FETCH NEXT 10 ROWS ONLY;'


SET @ParmDefinition = N'@ename varchar(100)';
SET @ename = 'mohapam@test.com';

EXECUTE SP_EXECUTESQL @sqlString, @ParmDefinition, @ename = @ename;

在这里，我试图根据分页获取记录数，并获得计数总数。当我执行上述查询时，它在语法 'COU 处显示错误。

请建议任何其他方式来获取总计数的记录。

Answer 1

如前所述，这里根本不需要sp_executesql。动态 SQL 是指您拥有一个动态的对象（顾名思义）。举个简单的例子，你不能有类似的东西：

DECLARE @TableName sysname = N'MyTable',
        @Name varchar(50) = 'Jane Smith';

SELECT *
FROM @TableName
WHERE [Name] = @Name;

这将返回一个错误，指出表变量@TableName 尚未声明。相反，您将执行以下操作：

DECLARE @TableName sysname = N'MyTable',
        @Name varchar(50) = 'Jane Smith';

DECLARE @SQL nvarchar(MAX);

SET @SQL = N'SELECT * FROM ' + QUOTENAME(@TableName) + N'WHERE [Name] = @Name;';

EXEC sp_executesql @SQL, N'@name varchar(50)', @Name;

但是，在您的陈述中，您没有动态对象；我们可以很容易地看到这一点，因为您没有在查询中注入任何对象名称。

此外，我们可以将子查询(SELECT COUNT(*) FROM Data_CTE) 更改为窗口函数，从而在表格上节省额外的罐头。这给出了下面的最终查询：

DECLARE @email varchar(100) = 'mohapam@test.com';

WITH Data_CTE AS
    (SELECT pj.ProjectID,
            pj.ProjectName,
            pj.ProjectOwner,
            cs.CustomerName,
            COUNT(*) OVER () AS TotalRows
     FROM Projects pj
          LEFT OUTER JOIN [Customers] cs ON pj.CustomerId = cs.CustomerID
     WHERE pj.ProjectOwner = @ename
       AND (pj.ProjectStatus = 1
         OR pj.ProjectStatus = 0))
SELECT ProjectID,
       ProjectName,
       ProjectOwner,
       CustomerName,
       DC.TotalRows
FROM Data_CTE DC
ORDER BY ProjectName OFFSET 0 * 10 ROWS FETCH NEXT 10 ROWS ONLY;

至于 为什么 您遇到了错误，如果您查看问题中文字字符串的长度，它超过 500 个字符，但您声明您将 @sqlString 定义为varchar(500)。结果，该值被截断，因此 SQL 不起作用。

Answer 2

您可以使用OVER 子句获取总行数。您无需使用CTE 使其复杂化。使用您的查询，如下所示。

SELECT pj.ProjectID, pj.ProjectName, pj.ProjectOwner, cs.CustomerName, COUNT(*) OVER() AS TotalRows
FROM Projects as pj
LEFT OUTER JOIN [Customers] cs
    ON pj.CustomerId = cs.CustomerID
WHERE  pj.ProjectOwner =  @ename 
    AND (pj.ProjectStatus = 1 OR pj.ProjectStatus = 0
ORDER BY pj.ProjectName
OFFSET 0 * 10 ROWS
FETCH NEXT 10 ROWS ONLY;

Click here for more details about OVER Clause