SELECT
`Distinct1`.`UserId`,
`Distinct1`.`FirstName`,
`Distinct1`.`LastName`,
`Distinct1`.`EmailAddress`,
FROM ( SELECT DISTINCT
`Extent2`.`UserId`,
`Extent2`.`FirstName`,
`Extent2`.`LastName`,
`Extent2`.`EmailAddress`,
FROM `AssistantTo` AS `Extent1`
INNER JOIN `User` AS `Extent2` ON `Extent1`.`AssistantId` = `Extent2`.`UserId`
INNER JOIN `CustomTagUser` as `Extent3` ON `Extent3`.`UserId` = `Extent2`.`UserId`
WHERE `Extent1`.`OwnerId` = 274 AND `Extent3`.`CustomTagId` = 114
) AS `Distinct1`
这是我的表结构:
我尝试使用以下查询,但它给了我错误。
var assistants =
dbContext.AssistantsTo
.Include(x => x.Assistant)
.Include(x => x.Assistant.CustomTagUser)
.Where(at =>
at.OwnerId == currentUser.UserId
&& (at.Assistant.CustomTagUser.Count(y => y.CustomTagId == filter) > 0)
)
.Select(at => at.Assistant)
.Distinct()
.ToList();
错误:{“‘where 子句’中存在未知列‘Extent1.AssistantId’”}
基本上我对提供过滤器有疑问
`Extent3`.`CustomTagId` = 114
我认为我们可以使用any(),但我在处理大数据和mysql时使用any()的经验很差。
模型类
public class AssistantTo
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int AssistantToId { get; set; }
public int AssistantId { get; set; }
[ForeignKey("AssistantId")]
public virtual User Assistant { get; set; }
public int OwnerId { get; set; }
[ForeignKey("OwnerId")]
public virtual User Owner { get; set; }
}
public class CustomTagUser
{
[Key]
public int CustomTagUserId { get; set; }
public int CustomTagId { get; set; }
public int UserId { get; set; }
public DateTime CreatedOn { get; set; }
[ForeignKey("CustomTagId")]
public virtual CustomTags CustomTags { get; set; }
[ForeignKey("UserId")]
public virtual User User { get; set; }
}
[Table("User")]
public class User
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int UserId { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string EmailAddress { get; set; }
public string Password { get; set; }
.....
public ICollection<CustomTagUser> CustomTagUser { get; set; }
}
}
Basically I have main problem with applying this part in EF
AND Extent3.CustomTagId = 114
最佳答案
var assistants =
dbContext.AssistantsTo
.Include(x => x.Assistant)
.Include(x => x.Assistant.CustomTagUser)
.Where(at =>
at.OwnerId == currentUser.UserId &&
(
at.Assistant.CustomTagUser.Select(x => x.CustomTagId).Contains(filter)
)
.Select(at => at.Assistant)
.Distinct()
.ToList();
试试这个...
关于c# - 如何使用 Entity Framework 和 Lambda 表达式编写下面的 mysql 查询?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/40276450/