Neo4j-CQL - Cypher操作符

操作符是对Cypher查询结果进行算术运算，逻辑运算等。

通用操作符

distinct 用于移除重复值， n.property 用于访问属性，[]是变量的列表

CREATE (a:Person { name: 'Anne', eyeColor: 'blue' }),(b:Person { name: 'Bill', eyeColor: 'brown' }),(c:Person { name: 'Carol', eyeColor: 'blue' })
WITH [a, b, c] AS ps
UNWIND ps AS p
RETURN DISTINCT p.eyeColor

算术操作符

• 加减乘除：+,-,*,/
• 取模：%
• 取幂：^

比较运算符

• 等于：=
• 不等于：<>
• 小于、大于、小于等于、大于等于：<、>、<=、>=
• IS NULL和 IS NOT NULL

逻辑运算符

与（AND）,或（OR）,异或（XOR）,非（NOT）

WITH [2, 4, 7, 9, 12] AS numberlist
UNWIND numberlist AS number
WITH number
WHERE number = 4 OR (number > 6 AND number < 10)
RETURN number

字符串操作

字符串拼接：+

匹配正则：=~

WITH ['mouse', 'chair', 'door', 'house'] AS wordlist
UNWIND wordlist AS word
WITH word
WHERE word =~ '.*ous.*'
RETURN word

对于字符串，使用 STARTS WITH、ENDS WITH和CONTAINS 过滤字符串：

WITH ['John', 'Mark', 'Jonathan', 'Bill'] AS somenames
UNWIND somenames AS names
WITH names AS candidate
WHERE candidate STARTS WITH 'Jo'
RETURN candidate

列表操作

• +，列表追加
• IN：检查成员
• []：索引，特殊地，[start .. end]，从start开始，递增1，但是不包括end

RETURN [1,2,3,4,5]+[6,7] AS myList

WITH [2, 3, 4, 5] AS numberlist
UNWIND numberlist AS number
WITH number
WHERE number IN [2, 3, 8]
RETURN number

WITH ['Anne', 'John', 'Bill', 'Diane', 'Eve'] AS names
RETURN names[1..3] AS result

访问属性

使用 . 号访问属性

MATCH (n) WHERE 21 < n.age AND n.age <= 30 RETURN n