LIMIT-PolarDB(PolarDB)-阿里云帮助中心

LIMIT constrains the number of rows returned by a Cypher query. It accepts any expression that evaluates to a positive integer, as long as the expression does not reference external variables.

Return a fixed number of rows

Pass a literal integer to cap the result set.

Example 1. Return the first three rows

SELECT *
FROM cypher('graph_name', $$
  MATCH (n) RETURN n.name
  ORDER BY n.name
  LIMIT 3
$$) as (names agtype);

Returns the name property of matched nodes, ordered alphabetically, capped at three rows.

names
"A"
"B"
"C"

(3 rows)

Return a variable number of rows using an expression

Pass an expression to make the limit dynamic. The expression must evaluate to a positive integer and must not reference any external variables.

Example 2. Return between one and three rows using a random limit

SELECT *
FROM cypher('graph_name', $$
  MATCH (n)
  RETURN n.name
  ORDER BY n.name
  LIMIT toInteger(3 * rand()) + 1
$$) as (names agtype);

toInteger(3 * rand()) + 1 evaluates to a random integer between 1 and 3. The following is an example result:

names
"A"
"B"

(2 rows)