不符合在 golang 中使用 gorm 的条件 - 动态不符合 select 语句的条件
Not in condition using gorm in golang - dynamic not in condition for select statement
我有两个数据库 Booking 和 Room。 Booking 将 roomid 作为其字段之一。我写了一个 select 语句,它将检索到的行保存在结果变量中,如下所述。
var result models.Booking
rows, err := utils.DB.Model(&currRequest).Where("check_in BETWEEN ? AND ? AND check_out BETWEEN ? AND ?", currRequest.CheckIn, currRequest.CheckOut, currRequest.CheckIn, currRequest.CheckOut).Select("room_id").Rows()
for rows.Next() {
utils.DB.ScanRows(rows, &result)
fmt.Println(result.RoomID)
}
现在我的 result.roomid 的 roomids 值满足来自预订 table
的 select 声明
我的结果变量可能有多个房间 ID 值。我能够通过遍历结果变量来检索 roomid 值。现在我必须检查名为 Room 的主房间数据库,并获取那些不在结果结构中的房间 ID。通过使用以下语句,我只能访问 result.roomid 中的第一个值,因此 not in 条件仅考虑 result.roomid 中的第一个值。如何对 result.roomid 中的所有值执行不符合条件?
rows, err := utils.DB.Model(&models.Room{}).Not(result.RoomID).Select("room_id").Rows()
完整代码:
package handlers
import (
"encoding/json"
"fmt"
"net/http"
"server/models"
"server/utils"
"strings"
)
func AvailableRoomsHandler(w http.ResponseWriter, r *http.Request) {
currRequest := &models.Booking{}
err := json.NewDecoder(r.Body).Decode(currRequest)
//check if a valid request has been sent from front end
if err != nil {
//fmt.Println(err)
var resp = map[string]interface{}{"status": false, "message": "Invalid json request"}
json.NewEncoder(w).Encode(resp)
return
}
noOfRoomsOccupied := 0
var notinrooms string
// Use GORM API build SQL
//check if any rooms are available which havent been booked yet in the requested check-in and check-out dates
var result models.Booking
rows, err := utils.DB.Model(&currRequest).Where("check_in BETWEEN ? AND ? AND check_out BETWEEN ? AND ?", currRequest.CheckIn, currRequest.CheckOut, currRequest.CheckIn, currRequest.CheckOut).Select("room_id").Rows()
if err != nil {
json.NewEncoder(w).Encode(err)
fmt.Print("error occured in select statement")
return
} else {
defer rows.Close()
for rows.Next() {
noOfRoomsOccupied = noOfRoomsOccupied + 1
utils.DB.ScanRows(rows, &result)
fmt.Println(result.RoomID)
notinrooms = notinrooms + result.RoomID + ","
}
notinrooms = strings.TrimRight(notinrooms, ",")
fmt.Println(notinrooms)
//calculate the number of rooms in the database
//rows, err := utils.DB.Model(&models.Room{}).Select("room_id").Rows()
res := utils.DB.Find(&models.Room{})
rowcount := res.RowsAffected
fmt.Println(rowcount)
if noOfRoomsOccupied == int(rowcount) {
var resp = map[string]interface{}{"status": false, "message": "no rooms available in the specified time period"}
json.NewEncoder(w).Encode(resp)
return
} else {
noOfRooms := (currRequest.NoOfGuests + currRequest.NoOfChildren) / 2
if (currRequest.NoOfGuests+currRequest.NoOfChildren)%2 == 1 {
noOfRooms = noOfRooms + 1
}
if int(noOfRooms) < int(rowcount)-noOfRoomsOccupied {
fmt.Println("number of rooms to book : ", noOfRooms)
//assign rooms if available
var roomids models.Room
//rows, err := utils.DB.Model(&models.Room{}).Not(result.RoomID).Select("room_id").Rows()
fmt.Println("rooms that can be booked")
rows, err := utils.DB.Model(&models.Room{}).Not(result.RoomID).Select("room_id").Rows()
//rows, err := utils.DB.Model(&models.Room{}).Not([]string{notinrooms}).Select("room_id").Rows()
//map[string]interface{}{"name": []string{"jinzhu", "jinzhu 2"}}
if err != nil {
json.NewEncoder(w).Encode(err)
fmt.Print("error occured in select statement to get room ids to assign")
return
} else {
defer rows.Close()
for rows.Next() {
noOfRoomsOccupied = noOfRoomsOccupied + 1
utils.DB.ScanRows(rows, &roomids)
fmt.Println(roomids.RoomID)
}
}
var success = map[string]interface{}{"message": "Select statement worked well"}
json.NewEncoder(w).Encode(success)
return
}
}
}
}
当我执行 result.roomid 时,它只给出第一个房间 ID,并只删除上面 select 语句中的那个房间 ID。如何消除房间 table 数据中预订 table 中找到的所有房间 ID?
我尝试拆分 result.roomid 值并尝试形成一个字符串并在 select 语句中提供它,但这没有用。我尝试遍历每个 result.roomid 和 运行 语句中的 not 但这没有任何意义。
使用此代码:
var result models.Booking
rows, err := utils.DB.Model(&currRequest).Where("check_in BETWEEN ? AND ? AND check_out BETWEEN ? AND ?", currRequest.CheckIn, currRequest.CheckOut, currRequest.CheckIn, currRequest.CheckOut).Select("room_id").Rows()
if err != nil {
json.NewEncoder(w).Encode(err)
fmt.Print("error occured in select statement")
return
} else {
defer rows.Close()
for rows.Next() {
noOfRoomsOccupied = noOfRoomsOccupied + 1
utils.DB.ScanRows(rows, &result)
//rest of the code
}
}
您只能从结果集中获得可能有很多行的一行。要获取所有行并提取它们的值,您应该使用 []models.Booking
.
result := []models.Booking{}
rows, err := utils.DB.Model(&currRequest).Where("check_in BETWEEN ? AND ? AND check_out BETWEEN ? AND ?", currRequest.CheckIn, currRequest.CheckOut, currRequest.CheckIn, currRequest.CheckOut).Select("room_id").Rows()
if err != nil {
json.NewEncoder(w).Encode(err)
fmt.Print("error occured in select statement")
return
} else {
defer rows.Close()
for rows.Next() {
var b models.Booking
noOfRoomsOccupied = noOfRoomsOccupied + 1
utils.DB.ScanRows(rows, &b)
result = append(result, b)
//rest of the code
}
}
但是,由于无论如何你只需要 roomid
,你可以使用 []uint
使它更容易(假设 roomid
是 uint
类型)。
result := []uint{}
rows, err := utils.DB.Model(&currRequest).Where("check_in BETWEEN ? AND ? AND check_out BETWEEN ? AND ?", currRequest.CheckIn, currRequest.CheckOut, currRequest.CheckIn, currRequest.CheckOut).Select("room_id").Rows()
if err != nil {
json.NewEncoder(w).Encode(err)
fmt.Print("error occured in select statement")
return
} else {
defer rows.Close()
for rows.Next() {
var rid uint
noOfRoomsOccupied = noOfRoomsOccupied + 1
utils.DB.ScanRows(rows, &rid)
result = append(result, rid)
//rest of the code
}
}
由于 result
是 []uint
类型,将它与 Not
函数一起使用会更容易(根据 documentation):
rows, err := utils.DB.Model(&models.Room{}).Not(result).Select("room_id").Rows()
我有两个数据库 Booking 和 Room。 Booking 将 roomid 作为其字段之一。我写了一个 select 语句,它将检索到的行保存在结果变量中,如下所述。
var result models.Booking
rows, err := utils.DB.Model(&currRequest).Where("check_in BETWEEN ? AND ? AND check_out BETWEEN ? AND ?", currRequest.CheckIn, currRequest.CheckOut, currRequest.CheckIn, currRequest.CheckOut).Select("room_id").Rows()
for rows.Next() {
utils.DB.ScanRows(rows, &result)
fmt.Println(result.RoomID)
}
现在我的 result.roomid 的 roomids 值满足来自预订 table
的 select 声明我的结果变量可能有多个房间 ID 值。我能够通过遍历结果变量来检索 roomid 值。现在我必须检查名为 Room 的主房间数据库,并获取那些不在结果结构中的房间 ID。通过使用以下语句,我只能访问 result.roomid 中的第一个值,因此 not in 条件仅考虑 result.roomid 中的第一个值。如何对 result.roomid 中的所有值执行不符合条件?
rows, err := utils.DB.Model(&models.Room{}).Not(result.RoomID).Select("room_id").Rows()
完整代码:
package handlers
import (
"encoding/json"
"fmt"
"net/http"
"server/models"
"server/utils"
"strings"
)
func AvailableRoomsHandler(w http.ResponseWriter, r *http.Request) {
currRequest := &models.Booking{}
err := json.NewDecoder(r.Body).Decode(currRequest)
//check if a valid request has been sent from front end
if err != nil {
//fmt.Println(err)
var resp = map[string]interface{}{"status": false, "message": "Invalid json request"}
json.NewEncoder(w).Encode(resp)
return
}
noOfRoomsOccupied := 0
var notinrooms string
// Use GORM API build SQL
//check if any rooms are available which havent been booked yet in the requested check-in and check-out dates
var result models.Booking
rows, err := utils.DB.Model(&currRequest).Where("check_in BETWEEN ? AND ? AND check_out BETWEEN ? AND ?", currRequest.CheckIn, currRequest.CheckOut, currRequest.CheckIn, currRequest.CheckOut).Select("room_id").Rows()
if err != nil {
json.NewEncoder(w).Encode(err)
fmt.Print("error occured in select statement")
return
} else {
defer rows.Close()
for rows.Next() {
noOfRoomsOccupied = noOfRoomsOccupied + 1
utils.DB.ScanRows(rows, &result)
fmt.Println(result.RoomID)
notinrooms = notinrooms + result.RoomID + ","
}
notinrooms = strings.TrimRight(notinrooms, ",")
fmt.Println(notinrooms)
//calculate the number of rooms in the database
//rows, err := utils.DB.Model(&models.Room{}).Select("room_id").Rows()
res := utils.DB.Find(&models.Room{})
rowcount := res.RowsAffected
fmt.Println(rowcount)
if noOfRoomsOccupied == int(rowcount) {
var resp = map[string]interface{}{"status": false, "message": "no rooms available in the specified time period"}
json.NewEncoder(w).Encode(resp)
return
} else {
noOfRooms := (currRequest.NoOfGuests + currRequest.NoOfChildren) / 2
if (currRequest.NoOfGuests+currRequest.NoOfChildren)%2 == 1 {
noOfRooms = noOfRooms + 1
}
if int(noOfRooms) < int(rowcount)-noOfRoomsOccupied {
fmt.Println("number of rooms to book : ", noOfRooms)
//assign rooms if available
var roomids models.Room
//rows, err := utils.DB.Model(&models.Room{}).Not(result.RoomID).Select("room_id").Rows()
fmt.Println("rooms that can be booked")
rows, err := utils.DB.Model(&models.Room{}).Not(result.RoomID).Select("room_id").Rows()
//rows, err := utils.DB.Model(&models.Room{}).Not([]string{notinrooms}).Select("room_id").Rows()
//map[string]interface{}{"name": []string{"jinzhu", "jinzhu 2"}}
if err != nil {
json.NewEncoder(w).Encode(err)
fmt.Print("error occured in select statement to get room ids to assign")
return
} else {
defer rows.Close()
for rows.Next() {
noOfRoomsOccupied = noOfRoomsOccupied + 1
utils.DB.ScanRows(rows, &roomids)
fmt.Println(roomids.RoomID)
}
}
var success = map[string]interface{}{"message": "Select statement worked well"}
json.NewEncoder(w).Encode(success)
return
}
}
}
}
当我执行 result.roomid 时,它只给出第一个房间 ID,并只删除上面 select 语句中的那个房间 ID。如何消除房间 table 数据中预订 table 中找到的所有房间 ID?
我尝试拆分 result.roomid 值并尝试形成一个字符串并在 select 语句中提供它,但这没有用。我尝试遍历每个 result.roomid 和 运行 语句中的 not 但这没有任何意义。
使用此代码:
var result models.Booking
rows, err := utils.DB.Model(&currRequest).Where("check_in BETWEEN ? AND ? AND check_out BETWEEN ? AND ?", currRequest.CheckIn, currRequest.CheckOut, currRequest.CheckIn, currRequest.CheckOut).Select("room_id").Rows()
if err != nil {
json.NewEncoder(w).Encode(err)
fmt.Print("error occured in select statement")
return
} else {
defer rows.Close()
for rows.Next() {
noOfRoomsOccupied = noOfRoomsOccupied + 1
utils.DB.ScanRows(rows, &result)
//rest of the code
}
}
您只能从结果集中获得可能有很多行的一行。要获取所有行并提取它们的值,您应该使用 []models.Booking
.
result := []models.Booking{}
rows, err := utils.DB.Model(&currRequest).Where("check_in BETWEEN ? AND ? AND check_out BETWEEN ? AND ?", currRequest.CheckIn, currRequest.CheckOut, currRequest.CheckIn, currRequest.CheckOut).Select("room_id").Rows()
if err != nil {
json.NewEncoder(w).Encode(err)
fmt.Print("error occured in select statement")
return
} else {
defer rows.Close()
for rows.Next() {
var b models.Booking
noOfRoomsOccupied = noOfRoomsOccupied + 1
utils.DB.ScanRows(rows, &b)
result = append(result, b)
//rest of the code
}
}
但是,由于无论如何你只需要 roomid
,你可以使用 []uint
使它更容易(假设 roomid
是 uint
类型)。
result := []uint{}
rows, err := utils.DB.Model(&currRequest).Where("check_in BETWEEN ? AND ? AND check_out BETWEEN ? AND ?", currRequest.CheckIn, currRequest.CheckOut, currRequest.CheckIn, currRequest.CheckOut).Select("room_id").Rows()
if err != nil {
json.NewEncoder(w).Encode(err)
fmt.Print("error occured in select statement")
return
} else {
defer rows.Close()
for rows.Next() {
var rid uint
noOfRoomsOccupied = noOfRoomsOccupied + 1
utils.DB.ScanRows(rows, &rid)
result = append(result, rid)
//rest of the code
}
}
由于 result
是 []uint
类型,将它与 Not
函数一起使用会更容易(根据 documentation):
rows, err := utils.DB.Model(&models.Room{}).Not(result).Select("room_id").Rows()