Loop exists

Use the If tag with loop exists to check if a loop has any items.

It is followed by a list of attributes for the Loop tag.

<If loop exists type=post name=example>

Inside the condition, use the Loop tag without attributes to loop through the result.

<If loop exists type=post name=example>
  <Loop>
    <Field title />
    ...
  </Loop>
</If>

For example, this lets you wrap the loop with a container element only when it has items.

Else

Use the Else tag for when the loop has no result.

<If loop exists type=post name=example>
  <Loop>
    ...
  </Loop>
<Else />
  Nothing found.
</If>

Not exists

Use the not attribute to only check if nothing exists.

<If not loop exists type=post name=example>
  Nothing found.
</If>

This may be useful if you don't need to loop through the results.