How to Efficiently Check for Record Existence and Insert if Absent in Go?

Checking for Record Existence and Inserting if Absent in Go

In the provided Go code, a query is executed to retrieve the sum of user counts from the category, sub_category, and industry tables for the category 'construction'. However, the code doesn't check whether the record exists before executing the query.

To check if a record exists and insert it if it doesn't, a possible approach is:

package main

import (
    "database/sql"
    "fmt"
    "os"

    "github.com/gin-gonic/gin"
)

func main() {
    router := gin.New()
    router.Use(gin.Logger())
    router.Use(gin.Recovery())
    dbUser := os.Getenv("DB_USER")
    dbPwd := os.Getenv("DB_PASSWORD")
    dbHost := os.Getenv("DB_HOST")
    dbPort := os.Getenv("DB_PORT")
    dbDatabase := os.Getenv("DB_NAME")
    db, err := sql.Open("mysql", fmt.Sprintf("%s:%s@tcp(%s:%s)/%s", dbUser, dbPwd, dbHost, dbPort, dbDatabase))
    if err != nil {
        fmt.Print(err.Error())
    }
    err = db.Ping()
    if err != nil {
        fmt.Print(err.Error())
    }

    var exists bool
    query := "SELECT EXISTS(SELECT 1 FROM ...)"
    row := db.QueryRow(query)
    if err = row.Scan(&exists); err != nil {
        return err
    }

    if !exists {
        query = "INSERT ...";
        if _, err = db.Exec(query); err != nil {
            return err
        }
    }
}

This code checks if the record exists by executing a query and storing the result in the exists variable. If the record doesn't exist, it proceeds to insert it into the database by executing another query.

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