不使用表达式树：
![引用内容]()
引用内容
使用表达式树：
![引用内容]()
引用内容
结论：使用表达式树生成的SQL语句不包含查询条件，这样返回的记录比不使用表达式树时多。
复制内容到剪贴板![程序代码]()
程序代码
程序代码var query = context.People.Where(item => item.Age == 20);
引用内容Select
[Extent1].[Id] AS [Id],
[Extent1].[Name] AS [Name],
[Extent1].[Age] AS [Age]
FROM [dbo].[Person] AS [Extent1]
Where 20 = [Extent1].[Age]
[Extent1].[Id] AS [Id],
[Extent1].[Name] AS [Name],
[Extent1].[Age] AS [Age]
FROM [dbo].[Person] AS [Extent1]
Where 20 = [Extent1].[Age]
使用表达式树：
复制内容到剪贴板![程序代码]()
程序代码
程序代码Expression<Func<Person, bool>> exp = item => item.Age == 20;
var query = context.People.Where(exp.Compile());
var query = context.People.Where(exp.Compile());
引用内容Select
[Extent1].[Id] AS [Id],
[Extent1].[Name] AS [Name],
[Extent1].[Age] AS [Age]
FROM [dbo].[Person] AS [Extent1]
[Extent1].[Id] AS [Id],
[Extent1].[Name] AS [Name],
[Extent1].[Age] AS [Age]
FROM [dbo].[Person] AS [Extent1]
结论：使用表达式树生成的SQL语句不包含查询条件，这样返回的记录比不使用表达式树时多。