In a Cypher query language for Neo4j, what is the difference between one MATCH clause immediately following another like this:

```
MATCH (d:Document{document_ID:2})
MATCH (d)--(s:Sentence)
RETURN d,s

```

Versus the comma-separated patterns in the same MATCH clause? E.g.:

```
MATCH (d:Document{document_ID:2}),(d)--(s:Sentence)
RETURN d,s

```

In this simple example the result is the same. But are there any "gotchas"?