Neo4j - Where Clause


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Like SQL, Neo4j CQL has provided WHERE clause in CQL MATCH command to filter the results of a MATCH Query.

Syntax

Following is the syntax of the WHERE clause.

MATCH (label)  
WHERE label.country = "property" 
RETURN label 

Example

Before proceeding with the example, create five nodes in the database as shown below.

CREATE(Dhawan:player{name:"shikar Dhawan", YOB: 1985, runs:363, country: "India"}
CREATE(Jonathan:player{name:"Jonathan Trott", YOB:1981, runs:229, country:"South Africa"}
CREATE(Sangakkara:player{name:"Kumar Sangakkara", YOB:1977, runs:222, 
   country:"Srilanka"})
CREATE(Rohit:player{name:"Rohit Sharma", YOB: 1987, runs:177, country:"India"})
CREATE(Virat:player{name:"Virat Kohli", YOB: 1988, runs:176, country:"India"})
CREATE(Ind:Country {name: "India", result: "Winners"})

Following is a sample Cypher Query which returns all the players (nodes) that belongs to the country India using WHERE clause.

MATCH (player)  
WHERE player.country = "India" 
RETURN player 

To execute the above query, carry out the following steps −

Step 1 − Open the Neo4j desktop App and start the Neo4j Server. Open the built-in browser app of Neo4j using the URL http://localhost:7474/ as shown in the following screenshot.

Browser App

Step 2 − Copy and paste the desired query in the dollar prompt and press the play button (to execute the query) highlighted in the following screenshot.

Where Player

Result

On executing, you will get the following result.

Where Result

WHERE Clause with Multiple Conditions

You can also use the WHERE clause to verify multiple conditions.

Syntax

Following is the syntax to use WHERE clause in Neo4j with multiple conditions.

MATCH (emp:Employee)  
WHERE emp.name = 'Abc' AND emp.name = 'Xyz' 
RETURN emp 

Example

Following is a sample Cypher Query which filters the nodes in the Neo4j database using two conditions.

MATCH (player)  
WHERE player.country = "India" AND player.runs >=175 
RETURN player 

To execute the above query, carry out the following steps −

Step 1 − Open the Neo4j desktop App and start the Neo4j Server. Open the built-in browser app of Neo4j using the URL http://localhost:7474/ as shown in the following screenshot.

Browser App

Step 2 − Copy and paste the desired query in the dollar prompt and press the play button (to execute the query) highlighted in the following screenshot.

Return Player

Result

On executing, you will get the following result.

Condition Result

Using Relationship with Where Clause

You can also use Where clause to filter the nodes using the relationships.

Example

Assume we have the following graph in the database.

Assumed Database

Following is a sample Cypher Query to retrieve the top scorer of India using WHERE clause as shown below.

MATCH (n) 
WHERE (n)-[: TOP_SCORER_OF]->( {name: "India", result: "Winners"}) 
RETURN n 

To execute the above query, carry out the following steps −

Step 1 − Open the Neo4j desktop App and start the Neo4j Server. Open the built-in browser app of Neo4j using the URL http://localhost:7474/ as shown in the following screenshot.

Browser App

Step 2 − Copy and paste the desired query in the dollar prompt and press the play button (to execute the query) highlighted in the following screenshot.

Winners Result

Result

On executing, you will get the following result. Here you can observe that Neo4j returned the node, which has the relation TOP_SCORER_OF to the country with the node having the name India.

Returned Node

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