C# SQL的LINQ等价物

我必须将下面的SQL查询转换为等效的LINQ

SELECT 
    0 AS DOCID, 
    'All_Forms ' as PAGE, 
    0 AS PAGENUMBER

UNION 

SELECT 
    DOCID,
    (CAST(IsNull(CUSTOMPAGE,PAGENUMBER) AS VARCHAR(10)) +'. '+TITLE ) AS PAGE,
    PAGENUMBER FROM Medical_Reports 
WHERE
    PAPERSTYLE='Normal' 
    AND PAGENUMBER<>10000 
ORDER BY
    docid

---

如何将上述内容转换为LINQ等价物？

假设您已经处理了数据库中的union并通过视图检索了数据，可能是这样的：

from reports in medicalReports
where reports.PaperStyle == "Normal"
&& reports.PageNumber != 10000
order by reports.DocId
select reports

---

注意：完全未经测试的代码。不保证。

使用基于SQL的仓促生成的表对此进行了测试。我希望这就是你想要的：

var firstItem = new List<dynamic>() { 
    new { DocId = 0, Page = "All_Forms ", PageNumber = 0}
};

var pages = (from p1 in firstItem
             select p1).Union(
             from p2 in MedicalReports
             where p2.PaperStyle == "Normal" &&
                    p2.PageNumber != 10000
             orderby p2.DocId
             select new
             {
                 DocId = p2.DocId,
                 Page = ((p2.CustomPage != null) ? p2.CustomPage : p2.PageNumber.ToString()) + ". " + p2.Title,
                 PageNumber = p2.PageNumber
             });

---

这是无效的SQL，在联合体的第一部分缺少FROM。@Abel:你不需要FROM子句，它是完全有效的。@Abel，不，如果你在SQL Server中执行它，你会得到结果，好吧，那就改变了，或者我有其他SQL方言中的bug…@Abel:也许你在想Oracle的FROM DUAL子句。

var firstItem = new List<dynamic>() { 
    new { DocId = 0, Page = "All_Forms ", PageNumber = 0}
};

var pages = (from p1 in firstItem
             select p1).Union(
             from p2 in MedicalReports
             where p2.PaperStyle == "Normal" &&
                    p2.PageNumber != 10000
             orderby p2.DocId
             select new
             {
                 DocId = p2.DocId,
                 Page = ((p2.CustomPage != null) ? p2.CustomPage : p2.PageNumber.ToString()) + ". " + p2.Title,
                 PageNumber = p2.PageNumber
             });