PostgreSQL wire: Go (pgx v5)

The only change

# host
 postgres.internal
 warehouse.internal
# port
 5432
 5432 (PostgreSQL wire)
# user / password / database
 PostgreSQL values
 MachWarehouse values

Run

go mod tidy
DATABASE_URL=postgresql://app:...@warehouse.internal:5432/demo go run .

Library: github.com/jackc/pgx/v5 v5.11.0 (Go 1.27).

Source

The program as it is kept and tested in the Mach Database Warehouse repository; highlighted lines read the connection setting.

go.mod

module example.com/machwarehouse/postgres-go

go 1.27

require github.com/jackc/pgx/v5 v5.11.0

main.go

// Command postgres-go aggregates over the PostgreSQL wire with pgx. Plain pgx code.
package main

import (
  "context"
  "fmt"
  "log"
  "os"

  "github.com/jackc/pgx/v5"
)

func main() {
  ctx := context.Background()
  conn, err := pgx.Connect(ctx, os.Getenv("DATABASE_URL"))
  if err != nil {
    log.Fatal(err)
  }
  defer conn.Close(ctx)

  rows, err := conn.Query(ctx, "SELECT country, count(*) AS events, sum(revenue)::text AS revenue FROM events GROUP BY country ORDER BY sum(revenue) DESC")
  if err != nil {
    log.Fatal(err)
  }
  defer rows.Close()
  for rows.Next() {
    var country, revenue string
    var events int64
    if err := rows.Scan(&country, &events, &revenue); err != nil {
      log.Fatal(err)
    }
    fmt.Printf("%s\t%d\t%s\n", country, events, revenue)
  }
  if err := rows.Err(); err != nil {
    log.Fatal(err)
  }
}