func selectDBVersion()

in pkg/datasource/sql/driver.go [196:244]
45 lines of code
10 McCabe index (conditional complexity)

func selectDBVersion(ctx context.Context, conn driver.Conn) (string, error) {
	var rowsi driver.Rows
	var err error

	queryerCtx, ok := conn.(driver.QueryerContext)
	var queryer driver.Queryer
	if !ok {
		queryer, ok = conn.(driver.Queryer)
	}
	if ok {
		rowsi, err = util.CtxDriverQuery(ctx, queryerCtx, queryer, "SELECT VERSION()", nil)
		defer func() {
			if rowsi != nil {
				rowsi.Close()
			}
		}()
		if err != nil {
			log.Errorf("ctx driver query: %+v", err)
			return "", err
		}
	} else {
		log.Errorf("target conn should been driver.QueryerContext or driver.Queryer")
		return "", fmt.Errorf("invalid conn")
	}

	dest := make([]driver.Value, 1)
	var version string
	if err = rowsi.Next(dest); err != nil {
		if err == io.EOF {
			return version, nil
		}
		return "", err
	}
	if len(dest) != 1 {
		return "", errors.New("get db version is not column 1")
	}

	switch reflect.TypeOf(dest[0]).Kind() {
	case reflect.Slice, reflect.Array:
		val := reflect.ValueOf(dest[0]).Bytes()
		version = string(val)
	case reflect.String:
		version = reflect.ValueOf(dest[0]).String()
	default:
		return "", errors.New("get db version is not a string")
	}

	return version, nil
}