dbcount.go

package main

import (
	"database/sql"
	"fmt"
	"log"

	_ "github.com/lib/pq"
)

const (
	host   = "localhost"
	port   = 5432
	dbname = "pkelly"
)

// pkelly=# create table late_attendance_daily (id int);
// CREATE TABLE
// pkelly=# insert into late_attendance_daily values (1), (2), (3);
// INSERT 0 3
// pkelly=# select count(*) from late_attendance_daily;
//  count
// -------
//      3
// (1 row)

// pkelly=# select count(id) from late_attendance_daily;
//  count
// -------
//      3
// (1 row)

// pkelly=# select count('id') from late_attendance_daily;
//  count
// -------
//      3
// (1 row)

func main() {

	psqlInfo := fmt.Sprintf("host=%s port=%d dbname=%s sslmode=disable",
		host, port, dbname)

	db, err := sql.Open("postgres", psqlInfo)
	if err != nil {
		log.Fatalf("%s", err.Error())
	}
	defer db.Close()

	row := db.QueryRow(`select count($1::text) from late_attendance_daily`, "id")

	var countVal int64

	err = row.Scan(&countVal)
	if err != nil {
		log.Fatalf("%s", err.Error())
	}

	fmt.Printf("%v\n", countVal)

	row = db.QueryRow(`select count(id) from late_attendance_daily`)

	err = row.Scan(&countVal)
	if err != nil {
		log.Fatalf("%s", err.Error())
	}

	fmt.Printf("%v\n", countVal)

}