需要有關轉換此 sql 查詢的幫助
SELECT c.studentId, c.Name
FROM Classes c
WHERE c.Class = 'Math'
AND c.Grade IN 'yoklama', '2')
AND c.studentId IN (
SELECT c2.studentId
FROM Classes c2
WHERE c2.Class = 'Eng'
AND c.Grade IN ('yoklama', '2'))
我正在嘗試這樣，但這些不斷給出錯誤，我做錯了
var reportDtos = context.Classes.Where(c => pt.Class == 'Math' && c.Grade.HasValue
&& c.Grade == '2' || c.Grade == 'yoklama' && c.studentId.Contains(context.ParticipTests
.Where(x => x.Class == 'Math' &&x.Grade.HasValue && x.Grade == '2' || x.Grade == 'yoklama')
.ToList()
.Select(x => ))
.Include("Area")
.Include("Questions")
.Include("Class.Test")
.ToList()
.Select(pt => new ReportDto
{
...
}
uj5u.com熱心網友回復：
首先，字串必須始終是雙引號，而不是像你有的"那樣單引號。'
如果您通過拆分步驟撰寫一些代碼，它會更容易理解。
var validGrades = new List<string> { "Yoklama", "2" };
var studentsInEnglish = context.ParticipTests
.Where(x => x.Class.Equals("Eng") && validGrades.Contains(x.Grade))
.Select(x => x.studentId);
var studentsInMath = context.Classes
.Where(x => x.Class.Equals("Math") && validGrades.Contains(x.Grade) && studentsInEnglish.Contains(x.studentId))
.Select(x => (x.studentId, x.Name));
現在有了這個，（如果你真的想要的話）你可以通過插入和替換來撰寫一個查詢。
var reportDtos = context.ParticipTests
.Where(
x => x.Class.Equals("Math") &&
new List<string> { "Yoklama", "2" }.Contains(x.Grade) &&
context.Classes
.Where(
y => y.Class.Equals("Eng") &&
new List<string> { "Yoklama", "2" }.Contains(y.Grade))
.Select(y => y.studentId)
.Contains(x.studentId))
.Select(x => (x.studentId, x.Name))
.ToList();
...但我更喜歡第一種方式。
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