Error Handling

pgx uses Go 1.13+ style error wrapping. That means that errors.Is() and errors.As() should be used instead of directly testing an error for equality or attempting a type assertion.

If an error is returned from PostgreSQL then underlying error type will be a *pgconn.PgError.

// Be sure the correct package is imported, this will not work if the old, standalone pgconn repo is imported instead.
import "github.com/jackc/pgx/v5/pgconn"

// ...

err = conn.QueryRow(context.Background(), "select 1 +").Scan(&greeting)
if err != nil {
  var pgErr *pgconn.PgError
  if errors.As(err, &pgErr) {
    fmt.Println(pgErr.Message) // => syntax error at end of input
    fmt.Println(pgErr.Code) // => 42601
  }
}