在 Golang 中同时运行多个查询，并从不同的数据库结构中检索结果

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我使用的是go 1.13 postgres 11 和 graphql

我正在尝试运行三个不同的查询： 1. 当某些条件成立时，获取少数员工的详细信息。 2. 获取所有员工的所有详细信息。 3. 获取符合empid的员工的所有详细信息。

当我运行代码时，它编译成功

但是当我调用（2 和 3）的 api 时，它说无法获取。 1 的 api 成功运行。

在浏览解决方案并尝试查找错误发生的位置时，它收敛于 rows.scan() 函数。

当我注释 rows.scan() 行时，它会在不提供数据的情况下运行，但在取消注释后运行时

显示错误：无法获取。

所以错误出在 rows.scan()

也许一个项目中不能有多于一行的 scan()。 考虑到这一点，我创建了一个函数，它接受查询语句并返回一个接口。

但这也不起作用。

connStr := fmt.Sprintf("port=%d host=%s user=%s password=%s dbname=%s sslmode=disable", hostport, hostname, username, password, databaseName)
    db, err := sql.Open("postgres", connStr)

    if err != nil {
        fmt.Println(`Could not connect to db`)
        panic(err)
    }
    defer db.Close()

    rows, err := db.Query(query)
    if err != nil {
        panic(err)
    }
    defer rows.Close()

    for rows.Next() {
        row := models.Universal{}
        if num == 1 {
            if err := rows.Scan(&row.AdhaarNo, &row.PersonalMobile, &row.Branch, &row.EmpID, &row.EmpName, &row.DOB, &row.DOJ, &row.Gender, &row.LocAdd1, &row.LocAdd2, &row.LocCity, &row.LocState, &row.LocCountry, &row.PerAdd1, &row.PerAdd2, &row.PerCity, &row.PerState, &row.PerCountry, &row.OfficeMail, &row.OfficeMobile, &row.LocPIN, &row.PerPIN, &row.MotherName, &row.PFNo, &row.BloodGroup, &row.PAN, &row.PersonalEmail, &row.FatherName, &row.EmergencyNo, &row.BankAcNo, &row.EmpBank, &row.IFSC, &row.Designation, &row.OnboardingStatus); err != nil {
                log.Fatal(err)
            }
            models.AllUniversal = append(models.AllUniversal, row)
        } else if num == 2 {
            if err := rows.Scan(&row.AdhaarNo, &row.PersonalMobile, &row.Branch, &row.EmpID, &row.EmpName, &row.DOB, &row.DOJ, &row.Gender, &row.LocAdd1, &row.LocAdd2, &row.LocCity, &row.LocState, &row.LocCountry, &row.PerAdd1, &row.PerAdd2, &row.PerCity, &row.PerState, &row.PerCountry, &row.OfficeMail, &row.OfficeMobile, &row.LocPIN, &row.PerPIN, &row.MotherName, &row.ESINo, &row.PAN, &row.VisaNo, &row.VisaExpiry, &row.IntegreationRef, &row.OrgID, &row.DeptID, &row.SectionID, &row.JobTypeID, &row.GradeID, &row.DesignationID, &row.CustomGroup1ID, &row.CustomGroup2ID, &row.CustomGroup3ID, &row.Card1, &row.Card2, &row.ScheduleGroupID, &row.StartShift, &row.PersonalEmail, &row.WeakOffGropuID, &row.LeaveGroup, &row.Field1, &row.PFNo, &row.BloodGroup, &row.SerialNo, &row.PassportNo, &row.PassportExpiry, &row.Dept, &row.JobType, &row.Level, &row.CostCenter, &row.FatherName, &row.EmergencyNo, &row.ConfirmationPeriod, &row.PFDate, &row.CTC, &row.FBP, &row.VarPay, &row.AdminBank, &row.EmpBank, &row.IFSC, &row.PayMode, &row.RepManager, &row.RepManEmail, &row.MaritalStatus, &row.SalaryTemp, &row.IsRepMan, &row.SpouseName, &row.Relation, &row.IsMetro, &row.HasESS, &row.HasPF, &row.PFUAN, &row.IsEPFEntitled, &row.HasESI, &row.IsPFRestricted, &row.BankAcNo, &row.Designation, &row.DeptCode, &row.Role, &row.JobTitle, &row.CustomField, &row.OnboardingStatus); err != nil {
                log.Fatal(err)
            }
            models.AllUniversal = append(models.AllUniversal, row)
        } else {
            if err := rows.Scan(&row.AdhaarNo, &row.Gender, &row.Branch, &row.EmpName, &row.DOB, &row.DOJ, &row.Gender, &row.LocAdd1, &row.LocAdd2, &row.LocCity, &row.LocState, &row.LocCountry, &row.PerAdd1, &row.PerAdd2, &row.PerCity, &row.PerState, &row.PerCountry, &row.OfficeMail, &row.OfficeMobile, &row.LocPIN, &row.PerPIN, &row.MotherName, &row.ESINo, &row.PAN, &row.VisaNo, &row.VisaExpiry, &row.IntegreationRef, &row.OrgID, &row.DeptID, &row.SectionID, &row.JobTypeID, &row.GradeID, &row.DesignationID, &row.CustomGroup1ID, &row.CustomGroup2ID, &row.CustomGroup3ID, &row.Card1, &row.Card2, &row.ScheduleGroupID, &row.StartShift, &row.PersonalEmail, &row.WeakOffGropuID, &row.LeaveGroup, &row.Field1, &row.PFNo, &row.BloodGroup, &row.SerialNo, &row.PassportNo, &row.PassportExpiry, &row.Dept, &row.JobType, &row.Level, &row.CostCenter, &row.FatherName, &row.EmergencyNo, &row.ConfirmationPeriod, &row.PFDate, &row.CTC, &row.FBP, &row.VarPay, &row.AdminBank, &row.EmpBank, &row.IFSC, &row.PayMode, &row.RepManager, &row.RepManEmail, &row.MaritalStatus, &row.SalaryTemp, &row.IsRepMan, &row.SpouseName, &row.Relation, &row.IsMetro, &row.HasESS, &row.HasPF, &row.PFUAN, &row.IsEPFEntitled, &row.HasESI, &row.IsPFRestricted, &row.BankAcNo, &row.Designation, &row.DeptCode, &row.Role, &row.JobTitle, &row.CustomField, &row.OnboardingStatus); err != nil {
                log.Fatal(err)
            }
            models.AllUniversal = append(models.AllUniversal, row)
        }
    }

    return models.AllUniversal
}

解决方案

由于我用来从数据库获取记录的查询，我遇到了“无法获取”错误。

由于少数列没有存储任何值，因此它们导致了错误。然后我使用“案例”技术来解决这些错误。

尽管相同的查询在 pgadmin 查询控制台中运行。

这种情况是必需的，因为我在中间使用了 graphql，而 graphql 无法处理这些空字段，因此如果字段值为 null，我将返回“N/A”。

在所有这些事情之前，我将多个查询传递给单个用户定义的函数，但后来我为返回单行和多行的查询创建了不同的函数。

这个东西有效并解决了所有错误。

谢谢。

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