<p>我有一个用于作业的表，一个用于解决方案的表，还有一个用于学生的表。 我想检索所有的作业，并且对于每个作业，我想添加一个“标志”，显示当前登录的学生是否尝试过该作业。</p> <p>我尝试了这个：</p> <pre class="brush:golang;toolbar:false;">import ( &quot;fmt&quot; &quot;gorm.io/gorm&quot; &quot;encoding/json&quot; &quot;github.com/my_organisation/myorg-repo/db&quot; ) var database *gorm.DB var solutions []db.Solution var listOfAsnmtIDs []uint func myfuncn (w http.ResponseWriter, r *http.Request){ //... _ = database.Table(&quot;solutions&quot;).Where(&quot;pupil_id = ?&quot;, pupil.ID).Select(&quot;assignment_id&quot;).Find(&amp;solutions) for _, solution := range solutions { listOfAsnmtIDs = append(listOfAsnmtIDs, solution.AssignmentID) } response := database.Table(&quot;assignments&quot;).Select(`id, created_at, IIF((id IN ?), 'attempted', 'Not attempted') as attempted`, listOfAsnmtIDs).Find(&amp;allAssignments) if response.RowsAffected &lt; 1 { respondToClient(w, 404, nil, &quot;No assignments found&quot;) return } //... } </pre></p>

    var mad string
    for i, solution := range solutions {
        mad += strconv.FormatUint(uint64(solution.AssignmentID), 10)
        if i != len(solutions) {
            mad += ","
        }
        listOfAsnmtIDs = append(listOfAsnmtIDs, solution.AssignmentID)
    }

    response := database.Table("assignments").Select(`id, created_at, IIF((id IN ?), 'attempted', 'Not attempted') as attempted`, mad).Find(&allAssignments)