$objOAuth2Credential = (new OAuth2TokenBuilder())->fromFile(PATH_ADWORDS_INI)
->build();
$objReportSetting = (new ReportSettingsBuilder())->includeZeroImpressions(true) <<< Set "includeZeroImpressions" property true.
->skipColumnHeader(true)
->skipReportHeader(true)
->skipReportSummary(true)
->build();
$objSession = (new AdWordsSessionBuilder())->fromFile(PATH_ADWORDS_INI)
->withOAuth2Credential($objOAuth2Credential)
->withReportSettings($objReportSetting)
->build();