“运算符不存在:整数=?"使用Postgres时 [英] "Operator does not exist: integer =?" when using Postgres

问题描述

我有一个简单的SQL查询，该查询在go的数据库/sql软件包提供的QueryRow方法内.

I have a simple SQL query called within the QueryRow method provided by go's database/sql package.

import (
  "github.com/codegangsta/martini"
  "github.com/martini-contrib/render"
  "net/http"
  "database/sql"
  "fmt"
  _ "github.com/lib/pq")
)

type User struct {
  Name string
}

func Show(db *sql.DB, params martini.Params) {
  id := params["id"]
  row := db.QueryRow(
    "SELECT name FROM users WHERE id=?", id)
  u := User{}
  err := row.Scan(&u.Name)
  fmt.Println(err)
}

但是，我收到错误pq: operator does not exist: integer =?，似乎代码无法理解?只是一个占位符.我该如何解决?

However, I'm getting the error pq: operator does not exist: integer =? It looks like the code doesn't understand that the ? is just a placeholder. How can I fix this?

推荐答案

PostgreSQL在本地使用带编号的占位符($1，$2，...)，而不是通常的位置问号. Go接口的文档在其示例中还使用了带编号的占位符:

PostgreSQL works with numbered placeholders ($1, $2, ...) natively rather than the usual positional question marks. The documentation for the Go interface also uses numbered placeholders in its examples:

rows, err := db.Query("SELECT name FROM users WHERE age = $1", age)

Go接口似乎没有像许多接口那样将问号转换为带编号的占位符，因此问号一直到数据库，并使所有内容混乱.

Seems that the Go interface isn't translating the question marks to numbered placeholders the way many interfaces do so the question mark is getting all the way to the database and confusing everything.

您应该能够切换到带编号的占位符，而不是问号:

You should be able to switch to numbered placeholders instead of question marks:

 row := db.QueryRow(
    "SELECT name FROM users WHERE id = $1", id)

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