COUNT is used to count the number of rows. COUNT can be used in two forms - COUNT(*) which just counts the number of matching rows, and COUNT(<identifier>), which counts the number of non-null values in <identifier>.

To count the number of nodes, for example the number of nodes connected to one node, you can use count(*).

Query

start n=(2) match (n)-->(x) return n, count(*)

The start node and the count of related nodes.

Result

 +--------------------------------------------+
 | n                               | count(*) |
 +--------------------------------------------+
 | Node[2]{name->"A",property->13} | 3        |
 +--------------------------------------------+
 1 rows, 2 ms

Instead of counting the number of results with count(*), it might be more expressive to include the name of the identifier you care about.

Query

start n=(2) match (n)-->(x) return count(x)

The number of connected nodes from the start node.

Result

 +----------+
 | count(x) |
 +----------+
 | 3        |
 +----------+
 1 rows, 2 ms

You can count the non-null values by using count(<identifier>).

Query

start n=(2,3,4,1) return count(n.property?)

The count of related nodes.

Result

 +-------------------+
 | count(n.property) |
 +-------------------+
 | 3                 |
 +-------------------+
 1 rows, 1 ms

The SUM aggregation function simply sums all the numeric values it encounters. Null values are silently dropped. This is an example of how you can use SUM.

Query

start n=(2,3,4) return sum(n.property)

The sum of all the values in the property property.

Result

 +-----------------+
 | sum(n.property) |
 +-----------------+
 | 90              |
 +-----------------+
 1 rows, 0 ms

AVG calculates the average of a numeric column.

Query

start n=(2,3,4) return avg(n.property)

The average of all the values in the property property.

Result

 +-----------------+
 | avg(n.property) |
 +-----------------+
 | 30.0            |
 +-----------------+
 1 rows, 1 ms

MAX find the largets value in a numeric column.

Query

start n=(2,3,4) return max(n.property)

The largest of all the values in the property property.

Result

 +-----------------+
 | max(n.property) |
 +-----------------+
 | 44              |
 +-----------------+
 1 rows, 0 ms

MIN takes a numeric property as input, and returns the smallest value in that column.

Query

start n=(2,3,4) return min(n.property)

The smallest of all the values in the property property.

Result

 +-----------------+
 | min(n.property) |
 +-----------------+
 | 13              |
 +-----------------+
 1 rows, 1 ms