Saturday, 28 August 2021

Neo4j: Where Clause

In my previous post, I explained how to filter the elements using properties. In this post, I am going to explain how to filter the elements using WHERE clause.

 

Example

MATCH(n:Person) WHERE n.age=32 RETURN n

 

Above statement return all the persons whose age is 32.

 

Let’s see some more examples to understand the usage of WHERE clause.

 

Step 1: Open neo4j browser by hitting following url in browser.

http://localhost:7474/browser/

 


 

Step 2: Insert data by executing below query.

CREATE (p1:Person{name: "Rama Krishna", age: 32, city: "Bangalore", male: true, designation: "CEO"}),
(p2:Person{name: "Murali", age: 32, city: "Hyderabad", male: true, designation: "Vice President"}),
(p3:Person{name: "Gopi", age: 34, city: "Chennai", male: true, designation: "Vice President"}),
(p4:Person{name: "Kiran", age: 28, city: "Bangalore", male: true, designation: "Director"}),
(p5:Person{name: "Siva", age: 45, city: "Hyderabad", male: true, designation: "Director"}),
(p6:Person{name: "Kiran", age: 36, city: "Hyderabad", male: true, designation: "Manager"}),
(p7:Person{name: "Ritweek", age: 23, city: "Bangalore", male: true, designation: "Manager"}),
(p8:Person{name: "Sudheer", age: 24, city: "Chennai", male: true, designation: "Manager"}),
(p9:Person{name: "Naveen", age: 37, city: "Bangalore", male: true, designation: "Employee"}),
(p10:Person{name: "Sailaja", age: 31, city: "Hyderabad", female: true, designation: "Employee"}),
(p11:Person{name: "Harika", age: 36, city: "Bangalore", female: true, designation: "Employee"}),
(p12:Person{name: "Brahmam", age: 41, city: "Bangalore", male: true, designation: "Employee"}),
(office1:Location{name: "Pluto", city: "Bangalore"}),
(office2:Location{name: "Mars", city: "Chennai"})
MERGE (p2)-[:REPORT_TO{from: 2014, description: "reports to"}]->(p1)
MERGE (p3)-[:REPORT_TO{from: 2016, description: "reports to"}]->(p1)
MERGE (p4)-[:REPORT_TO{from: 1997, description: "reports to"}]->(p2)
MERGE (p5)-[:REPORT_TO{from: 1997, description: "reports to"}]->(p3)
MERGE (p6)-[:REPORT_TO{from: 2001, description: "reports to"}]->(p4)
MERGE (p7)-[:REPORT_TO{from: 2009, description: "reports to"}]->(p4)
MERGE (p8)-[:REPORT_TO{from: 1998, description: "reports to"}]->(p5)
MERGE (p9)-[:REPORT_TO{from: 2003, description: "reports to"}]->(p6)
MERGE (p10)-[:REPORT_TO{from: 2004, description: "reports to"}]->(p6)
MERGE (p11)-[:REPORT_TO{from: 2008, description: "reports to"}]->(p7)
MERGE (p12)-[:REPORT_TO{from: 2019, description: "reports to"}]->(p8)
MERGE (p2)-[:FRIEND_TO{from: 2014, description: "friend to"}]->(p1)
MERGE (p10)-[:FRIEND_TO{from: 2014, description: "friend to"}]->(p8)
MERGE (p7)-[:FRIEND_TO{from: 2014, description: "friend to"}]->(p9)
MERGE (p3)-[:RELATIVE_TO{from: 2014, description: "relative to"}]->(p4)
RETURN p1, p2, p3, p4, p5, p6, p7, p8, p9, p10, p11, p12, office1, office2

 


 

Get all the persons who has property age with value 32

MATCH(n:Person) WHERE n.age=32 RETURN n

 

Get all the person names who are reporting to Rama Krishna

MATCH(n1:Person)<-[:REPORT_TO]->(n2) WHERE n1.name="Rama Krishna" RETURN n2.name

 

Get all the persons whose designation is Manager

MATCH (n:Person) WHERE n.designation="Manager" Return n

 

Get all the person name, age who are reporting to CEO directly

MATCH (n1)-[:REPORT_TO]->(n2:Person) WHERE n2.designation="CEO" Return n1.name, n1.age


 

 

 

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