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Filtering with WHERE  

Filter elements based on specific conditions. 
::WHERE(<condition>)
::WHERE(_::{property}::COMPARISON(value))
The condition in the WHERE step must evaluate to a boolean value. If the condition is not met, the element will be filtered out from the results.
When using the SDKs or curling the endpoint, the query name must match what is defined in the queries.hx file exactly.

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Comparison Operations

The following operations can be used to compare values. EQ and NEQ can be used to compare strings, booleans, and numbers. GT, GTE, LT, and LTE can only be used to compare numbers.

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String, Boolean, and Number Operations

OperationDescriptionExample
::EQ(value)Equals::WHERE(_::{status}::EQ("active"))
::NEQ(value)Not equals::WHERE(_::{age}::NEQ(25))

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Number Operations

OperationDescriptionExample
::GT(value)Greater than::WHERE(_::{age}::GT(25))
::LT(value)Less than::WHERE(_::{age}::LT(30))
::GTE(value)Greater than or equal::WHERE(_::{rating}::GTE(4.5))
::LTE(value)Less than or equal::WHERE(_::{priority}::LTE(2))

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Example 1: Basic filtering with WHERE

QUERY GetAdultUsers () =>
    adult_users <- N<User>::WHERE(_::{age}::GT(18))
    RETURN adult_users

QUERY CreateUser (name: String, age: U8, email: String) =>
    user <- AddN<User>({
        name: name,
        age: age,
        email: email
    })
    RETURN user
Here’s how to run the query using the SDKs or curl 
from helix.client import Client

client = Client(local=True, port=6969)

users = [
    {"name": "Alice", "age": 25, "email": "alice@example.com"},
    {"name": "Bob", "age": 16, "email": "bob@example.com"},
    {"name": "Charlie", "age": 30, "email": "charlie@example.com"},
    {"name": "Diana", "age": 17, "email": "diana@example.com"},
]

for user in users:
    client.query("CreateUser", user)

result = client.query("GetAdultUsers", {})
print(result)
For multiple conditions, see Multiple Conditional Steps.

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Example 2: String and equality filtering

QUERY GetActiveUsers (status: String) =>
    active_users <- N<User>::WHERE(_::{status}::EQ(status))
    RETURN active_users

QUERY CreateUser (name: String, age: U8, email: String, status: String) =>
    user <- AddN<User>({
        name: name,
        age: age,
        email: email,
        status: status
    })
    RETURN user
Here’s how to run the query using the SDKs or curl 
from helix.client import Client

client = Client(local=True, port=6969)

users = [
    {"name": "Alice", "age": 25, "email": "alice@example.com", "status": "active"},
    {"name": "Bob", "age": 30, "email": "bob@example.com", "status": "inactive"},
    {"name": "Charlie", "age": 28, "email": "charlie@example.com", "status": "active"},
    {"name": "Diana", "age": 22, "email": "diana@example.com", "status": "pending"},
]

for user in users:
    client.query("CreateUser", user)

result = client.query("GetActiveUsers", {"status": "active"})
print(result)

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Filter by Relationships with EXISTS  

Returns true if a traversal has any results. Otherwise, it returns false. 
EXISTS(<traversal>)

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Example 1: Using EXISTS for relationship filtering

QUERY GetUsersWithFollowers () =>
    users <- N<User>::WHERE(EXISTS(_::In<Follows>))
    RETURN users

QUERY CreateUser (name: String, age: U8, email: String) =>
    user <- AddN<User>({
        name: name,
        age: age,
        email: email
    })
    RETURN user

QUERY CreateFollow (follower_id: ID, following_id: ID) =>
    follower <- N<User>(follower_id)
    following <- N<User>(following_id)
    AddE<Follows>::From(follower)::To(following)
    RETURN "Success"
Here’s how to run the query using the SDKs or curl 
from helix.client import Client

client = Client(local=True, port=6969)

users = [
    {"name": "Alice", "age": 25, "email": "alice@example.com"},
    {"name": "Bob", "age": 30, "email": "bob@example.com"},
    {"name": "Charlie", "age": 28, "email": "charlie@example.com"},
]

user_ids = []
for user in users:
    result = client.query("CreateUser", user)
    user_ids.append(result[0]["user"]["id"])

client.query("CreateFollow", {"follower_id": user_ids[1], "following_id": user_ids[0]})
client.query("CreateFollow", {"follower_id": user_ids[2], "following_id": user_ids[0]})

result = client.query("GetUsersWithFollowers", {})
print(result)