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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.
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.
Result
On executing, you will get the following 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.
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.
Result
On executing, you will get the following 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.
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.
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.
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.
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