COUNT

COUNT(*) counts incoming rows. COUNT(value) counts non-null values; graph element references are valid values. DISTINCT removes duplicate values before counting.

FOR value IN [1, 1, 2, NULL]
RETURN COUNT(*) AS rows, COUNT(value) AS present, COUNT(DISTINCT value) AS distinct_values;

This returns 4, 3 and 2. Counting an absent optional element returns zero for that group, while COUNT(*) still counts the padded row. An empty global aggregate returns one row with zero.

See grouping and OPTIONAL MATCH for per-node counts.