title: Fetching NULL datetime value in MySQL using GORM
body: <p>I want to fetch the last visit_details row having out_time as <code>NULL</code> using Gorm.
  <code>NIL</code> is itself a type where VisitDetail OutTime is <code>mysql.NullTime</code>. </p>
  
  <p><strong>Code:-</strong></p>
  
  <pre><code>var visitDetail models.VisitDetail
  db.Where("out_time=? ", nil).Last(&amp;visitDetail)
  
  //model VisitDetails
  type VisitDetail struct {
      Id              int
      Visitor         Visitor  `gorm:"foreignkey:ClientId;association_foreignkey:Id"`
      VisitorId       int      `gorm:"not null;"`
      Location        Location `gorm:"foreignkey:LocationId;association_foreignkey:Id"`
      LocationId      int      `gorm:"not null;"`
      Purpose         string
      InTime          time.Time `gorm:"not null;"`
      OutTime         mysql.NullTime
      User            User `gorm:"foreignkey:ClientId;association_foreignkey:Id"`
      UserId          int  `gorm:"not null;"`
      Status          int  `gorm:"not null;"`
      ApproveByClient int  `gorm:"not null;"`
  }
  </code></pre>
  
  <p><strong>Query:-</strong></p>
  
  <pre><code>select * from visit_details where out_time is NULL order by id desc limit 1;
  +----+------------+-------------+---------+---------------------+----------+---------+--------+-------------------+
  | id | visitor_id | location_id | purpose | in_time             | out_time | user_id | status | approve_by_client |
  +----+------------+-------------+---------+---------------------+----------+---------+--------+-------------------+
  | 20 |          1 |           8 |         | 2018-02-20 17:13:25 | NULL     |    1609 |      0 |                 0 |
  +----+------------+-------------+---------+---------------------+----------+---------+--------+-------------------+
  1 row in set (0.04 sec)
  </code></pre>