douyin7829 2017-04-14 07:57
浏览 71
已采纳

IN pq.Array无法传递值

I have the following code:

package main

import (
    "database/sql"
    "fmt"
    "github.com/lib/pq"
)

const (
    DB_USER     = "<username>"
    DB_PASSWORD = "<password>"
    DB_NAME     = "<db>"
)

func main() {
    dbinfo := fmt.Sprintf("user=%s password=%s dbname=%s sslmode=disable",
    DB_USER, DB_PASSWORD, DB_NAME)

    db, err := sql.Open("postgres", dbinfo)
    checkErr(err)
    defer db.Close()

    fmt.Println("# Querying with blacklist in SQL")
    rows, err := db.Query(`
    SELECT * FROM(
        SELECT x from (values ('A'), ('B'), ('C') ) s(x)
    ) As Res1 WHERE x NOT IN ('A');
`)
    checkErr(err)

    for rows.Next() {
        var str string
        err = rows.Scan(&str)
        fmt.Println(str) // Prints B,C
    }

    fmt.Println("Querying with blacklist in Golang")
    blacklist := []string{"A"}

    q := `
    SELECT * FROM(
        SELECT x from (values ('A'), ('B'), ('C') ) s(x)
    ) As Res1 WHERE x NOT IN ($1);

`
    rows, err = db.Query(q, pq.Array(blacklist))
    checkErr(err)

    for rows.Next() {
        var str string
        err = rows.Scan(&str)
        fmt.Println(str) // Prints A, B, C
    }
}

func checkErr(err error) {
    if err != nil {
        panic(err)
    }
}

where I pass a pq.Array as a parameter to a Golang Postgres format string $1. However the parameter fails to get passed. When I expect an output of B,C, the program is printing A,B,C.

# Querying with blacklist in SQL
B
C
Querying with blacklist in Golang
A
B
C
  • 写回答

1条回答 默认 最新

  • duanhuo0577 2017-04-14 09:00
    关注

    Postgres's IN does not take an array like for example ANY or ALL which is where you can use pq.Array.

    Instead of using x NOT IN($1) you can use x <> ALL($1).

    From ALL's docs.

    The left-hand expression is evaluated and compared to each element of the array using the given operator, which must yield a Boolean result. The result of ALL is "true" if all comparisons yield true (including the case where the array has zero elements). The result is "false" if any false result is found.

    本回答被题主选为最佳回答 , 对您是否有帮助呢?
    评论

报告相同问题?

悬赏问题

  • ¥15 飞机曲面部件如机翼,壁板等具体的孔位模型
  • ¥15 vs2019中数据导出问题
  • ¥20 云服务Linux系统TCP-MSS值修改?
  • ¥20 关于#单片机#的问题:项目:使用模拟iic与ov2640通讯环境:F407问题:读取的ID号总是0xff,自己调了调发现在读从机数据时,SDA线上并未有信号变化(语言-c语言)
  • ¥20 怎么在stm32门禁成品上增加查询记录功能
  • ¥15 Source insight编写代码后使用CCS5.2版本import之后,代码跳到注释行里面
  • ¥50 NT4.0系统 STOP:0X0000007B
  • ¥15 想问一下stata17中这段代码哪里有问题呀
  • ¥15 flink cdc无法实时同步mysql数据
  • ¥100 有人会搭建GPT-J-6B框架吗?有偿