The form html looks like:

<form>

Category:<br />

<input name="category1" value="Users" type="checkbox" />Users<br />

<input name="category2" value="Assets" type="checkbox" />Assets<br />

<input name="category3" value="Collaboration" type="checkbox" />Collaboration<br />

<input name="category4" value="Advanced" type="checkbox" />Advanced<br />

Search for an asset with keyword: <input name="searchtitle" type="text" /><br />

<input value="submit" type="submit" />

</form>

The placeholders are:

form:searchtitle
form:searchtitle
form:category1
form:category2
form:category3
form:category4

The query is: 

SELECT DISTINCT
  title,
  url
FROM
  assetData
LEFT JOIN
  metaData_values
USING 
  (assetId)
WHERE
  title like concat('%',?,'%')
AND
  ? <> ''
AND
(
    metaData_values.value = concat('',?,'')
  OR
    metaData_values.value = concat('',?,'')
  OR
    metaData_values.value = concat('',?,'')
  OR
    metaData_values.value = concat('',?,'')
)
AND
  assetData.revisionDate = (SELECT MAX(maxAssetData.revisionDate) FROM assetData as maxAssetData where assetData.assetId=maxAssetData.assetId) 

The template looks like:

<a name="id<tmpl_var assetId>" id="id<tmpl_var assetId>"></a>

<tmpl_if session.var.adminOn>
	<p><tmpl_var controls></p>
</tmpl_if>

<tmpl_if displayTitle>
	<h2><tmpl_var title></h2>
</tmpl_if>

<tmpl_if description>
	<tmpl_var description>
	<p />
</tmpl_if>

<tmpl_if debugMode>
	<ul>
	<tmpl_loop debug_loop>
		<li><tmpl_var debug.output></li>
	</tmpl_loop>
	</ul>
</tmpl_if>

<tmpl_loop rows_loop>
<a href="<tmpl_var row.field.url.value>"><tmpl_var row.field.title.value></a><br />
</tmpl_loop>