Database

We will use the database, whose schema and data import commands are given here:

You can import this database by copy pasting the commands on that page.

UNWIND

UNWIND allows you to “unnest” a list L that has k elements in it, into a table T with k element. When using UNWIND, you need to specify an alias to refer to the elements of the unnested list, i.e., T.

For example, the following unnests a literal “list of strings” into multiple rows and return them:

Query:

UNWIND ["Amy", "Bob", "Carol"] AS x
RETURN x;

Output:

---------
| x     |
---------
| Amy   |
---------
| Bob   |
---------
| Carol |
---------

View example in Colab.

If the unwinded list L contained as elements other lists, then the output would be elements with one fewer nesting. For example, if L was a list of list of strings, after unwinding, you’d get a table of list of strings. For example:

UNWIND [["Amy"], ["Bob", "Carol"]] AS x
RETURN x;

Output:

---------------
| x           |
---------------
| [Amy]       |
---------------
| [Bob,Carol] |
---------------

View example in Colab.