我正在使用SQLKata
在SQL
中建立一个C#
语句,并在Github论坛上找到了一些代码,但没有编译。我需要帮助使其编译。
此行query.Where(q =>
上我收到两个错误
编译错误(第17行,第16行):并非所有代码路径都在lambda表达式中返回“ System.Func”类型的值
编译错误(第17行,第16行):无法将lambda表达式转换为类型“对象”,因为它不是委托类型
class Group
{
public List<Condition> Conditions {get; set;}
}
class Condition
{
public string Field {get; set;}
public string Operator {get; set;}
public object Value {get; set;}
}
var query = new Query("Countries");
foreach(Group group in groups)
{
query.Where(q =>
{
foreach(Condition c in group.Conditions)
{
q.OrWhere(c.Field, c.Operator, c.Value);
}
});
}
.NET Fiddle是here
Github帖子here
更新 我根据亚历克斯的回答更新了小提琴。我正在寻找一个子句,因此预期的输出是将OR语句括在括号中。现在,大多数情况都按预期运行,除了每个组都应位于自己的括号内,如下所示:
选择*从[国家/地区]在([Group1Field1] = @ p0或[Group1Field2]> @ p1或[Group1Field3] <@ p2或[Group1Field4] = @ p3)或([Group2Field1] = @ p4或[Group2Field2 ]> = @ p5或[Group2Field3] <= @ p6)和[Id] = @ p7
最终更新 弄清楚了。给出以上预期的输出。谢谢。
var query = new Query("Countries");
foreach (Group group in groups)
{
query.OrWhere(q => {
foreach (Condition c in group.Conditions)
{
q.OrWhere(c.Field, c.Operator, c.Value);
}
return q;
});
}
query.Where("Id", "=", 10);
答案 0 :(得分:1)
尝试一下:
{% for image in images %}
输出为:
List<Group> groups = new List<Group>
{
new Group
{
Conditions = new List<Condition>
{
new Condition {Field = "Group1Field1", Operator = "=", Value="Group1Value1"},
new Condition {Field = "Group1Field2", Operator = ">", Value="Group1Value2"},
new Condition {Field = "Group1Field3", Operator = "<", Value="Group1Value3"},
new Condition {Field = "Group1Field4", Operator = "=", Value="Group1Value4"}
}
},
new Group
{
Conditions = new List<Condition>
{
new Condition {Field = "Group2Field1", Operator = "=", Value="Group2Value1"},
new Condition {Field = "Group2Field2", Operator = ">=", Value="Group2Value2"},
new Condition {Field = "Group2Field3", Operator = "<=", Value="Group2Value3"}
}
}
};
var query = new Query("Countries");
foreach (Group group in groups)
foreach (Condition c in group.Conditions)
query.OrWhere(c.Field, c.Operator, c.Value);
Console.WriteLine(new SqlServerCompiler().Compile(query).Sql);
更新:
我检查了documentation和tests,没有发现比以下更好的东西。 要获得输出,您需要使用:
SELECT * FROM [Countries] WHERE [Group1Field1] = @p0 OR [Group1Field2] > @p1 OR [Group1Field3] < @p2 OR [Group1Field4] = @p3 OR [Group2Field1] = @p4 OR [Group2Field2] >= @p5 OR [Group2Field3] <= @p6
代替:
foreach (var group in groups)
{
if (!group.Conditions.Any())
continue;
if (group.Conditions.Count == 1)
{
var single = group.Conditions.Single();
query.OrWhereRaw($"([{single.Field}] {single.Operator} ?)", single.Value);
continue;
}
var first = group.Conditions.First();
var last = group.Conditions.Last();
var others = group.Conditions.Skip(1).Take(group.Conditions.Count - 2);
query.OrWhereRaw($"([{first.Field}] {first.Operator} ?", first.Value);
foreach (var c in others)
query.OrWhere(c.Field, c.Operator, c.Value);
query.OrWhereRaw($"[{last.Field}] {last.Operator} ?)", last.Value);
}
query.Where("Id", "=", 10);
答案 1 :(得分:0)
我已经更新了代码以修复错误。
var query = new Query("Countries");
foreach (Group group in groups)
{
query.OrWhere(q => {
foreach (Condition c in group.Conditions)
{
q.OrWhere(c.Field, c.Operator, c.Value);
}
return q;
});
}
query.Where("Id", "=", 10);