在GORM中按日期过滤 [英] Filtering by date in GORM

问题描述

我正在使用 GORM 访问我数据库中的记录.现在，我要检索所有未删除的记录，这意味着属性DeletedAt必须为NULL.

I'm using GORM to access the records in my database. Now I want to retrieve all records that are not deleted which means, that the attribute DeletedAt must be NULL.

我使用 WHERE() 尝试了以下命令链，但未返回任何结果.

I tried the following command chains with WHERE(), but they returned no results.

users := []*models.User{}
db.Where("deleted_at", nil).Find(&users)

和

db.Where("deleted_at", "NULL").Find(&users)

我的数据库模型由以下结构定义:

My database model is defined by the following structs:

type Model struct {
    ID        uint `gorm:"primary_key"`
    CreatedAt time.Time
    UpdatedAt time.Time
    DeletedAt *time.Time
}

type User struct {
    gorm.Model
    Username string `sql:"size:32; not null; unique"`
    Password string `sql:"not null"`
    Locale   string `sql:"not null"`
}

推荐答案

对于所有RDBMS，SQL标准都要求涉及与NULL值进行比较的条件始终为false.因此，以下查询始终返回空结果:

With all RDBMS, the SQL standard mandates that a condition involving a comparison with a NULL value is always false. The following query therefore always returns an empty result:

select * from XXX where deleted_at = NULL

如果要搜索NULL值，则应编写:

If you want to search for NULL values, you are supposed to write:

select * from XXX where deleted_at is null

我认为您可以通过确保GORM生成正确的查询来解决此问题.例如，这应该可以工作(未经测试):

I think you can fix the issue by making sure GORM generates the correct query. For instance, this should work (untested):

db.Where("deleted_at is null").Find(&users)

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