Thursday, 9 September 2021

Neo4j: COUNT: Number of items matches to given criteria

COUNT() function return number of items that matches to given criteria.

 

Find the below examples.

 

Count number of managers in the organizaiton

MATCH (n:Person{designation:"Manager"}) RETURN COUNT(n)

 

Count number of employees who are reporting to Manager directly.

MATCH (n1:Person{designation:"Manager"})<-[:REPORT_TO]-(n2:Person{designation:"Employee"}) RETURN COUNT(n2)

 

Count number of employees who are reporting to the director "Kiran"

MATCH (n1:Person{designation:"Manager", name:"Kiran"})<-[:REPORT_TO]-(n2:Person{designation:"Employee"}) RETURN COUNT(n2)

 

Let’s see the same with an example.

 

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", salary:540000000}),
(p2:Person{name: "Murali", age: 32, city: "Hyderabad", male: true, designation: "Vice President", salary: 43000000}),
(p3:Person{name: "Gopi", age: 34, city: "Chennai", male: true, designation: "Vice President", salary: 63067000}),
(p4:Person{name: "Kiran", age: 28, city: "Bangalore", male: true, designation: "Director", salary: 12000000}),
(p5:Person{name: "Siva", age: 45, city: "Hyderabad", male: true, designation: "Director", salary: 23000000}),
(p6:Person{name: "Kiran", age: 36, city: "Hyderabad", male: true, designation: "Manager", salary: 7800000}),
(p7:Person{name: "Ritweek", age: 23, city: "Bangalore", male: true, designation: "Manager", salary: 8100000}),
(p8:Person{name: "Sudheer", age: 24, city: "Chennai", male: true, designation: "Manager", salary: 7900000}),
(p9:Person{name: "Naveen", age: 37, city: "Bangalore", male: true, designation: "Employee", salary: 4500000}),
(p10:Person{name: "Sailaja", age: 31, city: "Hyderabad", female: true, designation: "Employee", salary: 5300000}),
(p11:Person{name: "Harika", age: 36, city: "Bangalore", female: true, designation: "Employee", salary: 3400000}),
(p12:Person{name: "Brahmam", age: 41, city: "Bangalore", male: true, designation: "Employee", salary: 4560000}),
(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

 

 


Count number of managers in the organizaiton

MATCH (n:Person{designation:"Manager"}) RETURN COUNT(n)


 


Count number of employees who are reporting to Manager directly.

MATCH (n1:Person{designation:"Manager"})<-[:REPORT_TO]-(n2:Person{designation:"Employee"}) RETURN COUNT(n2)




Count number of employees who are reporting to the director "Kiran"

MATCH (n1:Person{designation:"Manager", name:"Kiran"})<-[:REPORT_TO]-(n2:Person{designation:"Employee"}) RETURN COUNT(n2)

 


 

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