Dear All,
I have one dialog , where I have defined skuid , installation label and installation link , as shown below.

Now , my requirement is that if Sku ID is blank ("null") then it will display the installation document link in sightly
if Sku ID is not blank ("not null") then it will display the Sku ID link in sightly.
For above , I have written below in the sightly. But it is not working fine , as shown below.
**************SIGHTLY CODE **********************
<div class="installation-documents" data-sly-use.installationdocuments="com.sunita.core.components.models.InstallationDocumentModel">
<h2 class="installation_header">${installationdocuments.header}</h2>
<div>${installationdocuments.description @CONTEXT = 'html'}</div>
<!-- <div><h3>${installationdocuments.skuid}</h3></div> -->
<sly data-sly-test="${installationdocuments.skuid == '' || installationdocuments.skuid == null}">
<h2> Sku-ID null</h2>
<ul>
<a class="new-tab" href="http://localhost:4502/assetdetails.html${installationdocuments.installationLink}" target="_blank">
${installationdocuments.installationLabel}
</a>
</ul>
</sly>
<sly data-sly-test="${installationdocuments.skuid != '' || installationdocuments.skuid != null}">
<h2> Sku-ID not null</h2>
<ul>
<a class="new-tab" href="http://localhost:4502/assetdetails.html/content/dam/referencesite/bathroomproducts/${installationdocuments.skuid}.pdf" target="_blank">
${installationdocuments.installationLabel}
</a>
</ul>
</sly>
</div>