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GraphQL - Conditional filters

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TIP: Try these queries

You can try these queries on our demo instance (https://edu-demo.weaviate.network). You can authenticate against it with the read-only Weaviate API key learn-weaviate, and run the query with your preferred Weaviate client.


We include client instantiation examples below:

edu-demo client instantiation
import weaviate

# Instantiate the client with the auth config
client = weaviate.Client(
url="https://edu-demo.weaviate.network",
auth_client_secret=weaviate.AuthApiKey(api_key="learn-weaviate"),
additional_headers={
"X-OpenAI-Api-Key": "YOUR-OPENAI-API-KEY", # Only needed for `nearText` or `hybrid` queries
},
)

Overview​

Conditional filters can be added to queries on the class level. The operator used for filtering is also called a where filter.

Single operand (condition)​

Each set of algebraic conditions is called an "operand". For each operand, the required properties are:

  • The GraphQL property path,
  • The operator type, and
  • The valueType with the value.

For example, this filter will only allow objects from the class Article with a wordCount that is GreaterThan than 1000.

import weaviate

client = weaviate.Client("http://localhost:8080")

where_filter = {
"path": ["wordCount"],
"operator": "GreaterThan",
"valueInt": 1000
}

query_result = (
client.query
.get("Article", "title")
.with_where(where_filter)
.do()
)

print(query_result)
Expected response
{
"data": {
"Get": {
"Article": [
{
"title": "Anywhere but Washington: an eye-opening journey in a deeply divided nation"
},
{
"title": "The world is still struggling to implement meaningful climate policy"
},
...
]
}
}
}

Filter structure​

Supported by the Get{} and Aggregate{} functions.

The where filter is an algebraic object, which takes the following arguments:

  • Operator (which takes one of the following values)

    • And
    • Or
    • Equal
    • NotEqual
    • GreaterThan
    • GreaterThanEqual
    • LessThan
    • LessThanEqual
    • Like
    • WithinGeoRange
    • IsNull
  • Operands: Is a list of Operator objects of this same structure, only used if the parent Operator is set to And or Or.

  • Path: Is a list of strings in XPath style, indicating the property name of the class. If the property is a beacon (i.e., cross-reference), the path should be followed to the property of the beacon which should be specified as a list of strings. For a schema structure like:

    {
    "inPublication": {
    "Publication": {
    "name": "Wired"
    }
    }
    }

    Here, the path selector for name will be ["inPublication", "Publication", "name"].

  • valueType

Example filter structure​

{
Get {
<Class>(where: {
operator: <operator>,
operands: [{
path: [path],
operator: <operator>
<valueType>: <value>
}, {
path: [<matchPath>],
operator: <operator>,
<valueType>: <value>
}]
}) {
<propertyWithBeacon> {
<property>
... on <ClassOfWhereBeaconGoesTo> {
<propertyOfClass>
}
}
}
}
}

Available valueType values​

  • valueInt: The integer value that the last property in the Path selector should be compared to.
  • valueBoolean: The boolean value that the last property in Path should be compared to.
  • valueString: The string value that the last property in Path should be compared to. (Note: string has been deprecated.)
  • valueText: The text value that the last property in Path should be compared to.
  • valueNumber: The number (float) value that the last property in Path should be compared to.
  • valueDate: The date (ISO 8601 timestamp, formatted as RFC3339) value that the last property in Path should be compared to.

Filter behavior of multi-word queries in Equal operator​

The behavior for the Equal operator on multi-word textual properties in where filters depends on the tokenization of the property.

Refer to this section on the difference between the two types.

Stopwords in text/string filter values​

Starting with v1.12.0 you can configure your own stopword lists for the inverted index.

Example response​

{
"data": {
"Get": {
"Article": [
{
"title": "Opinion | John Lennon Told Them β€˜Girls Don't Play Guitar.' He Was So Wrong."
}
]
}
},
"errors": null
}

Filter by id​

You can filter object by their unique id or uuid, where you give the id as valueText.

import weaviate
import json

client = weaviate.Client("http://localhost:8080")

where_filter = {
"path": ["id"],
"operator": "Equal",
"valueText": "00037775-1432-35e5-bc59-443baaef7d80"
}

response = (
client.query
.get("Article", "title")
.with_where(where_filter)
.do()
)

print(json.dumps(response, indent=2))
Expected response
{
"data": {
"Get": {
"Article": [
{
"title": "Backs on the rack - Vast sums are wasted on treatments for back pain that make it worse"
}
]
}
}
}

Filter by timestamps​

Filtering can be performed with internal timestamps as well, such as creationTimeUnix and lastUpdateTimeUnix. These values can be represented either as Unix epoch milliseconds, or as RFC3339 formatted datetimes. Note that epoch milliseconds should be passed in as a valueText, and an RFC3339 datetime should be a valueDate.

info

Filtering by timestamp requires the target class to be configured to index timestamps. See here for details.

import weaviate

client = weaviate.Client("http://localhost:8080")

where_filter = {
"path": ["_creationTimeUnix"],
"operator": "GreaterThan",
# "valueDate": "2022-03-18T20:26:34.586-0500",
"valueText": "1647653359063"
}

response = (
client.query
.get("Article", "title")
.with_where(where_filter)
.do()
)

print(response)
Expected response
{
"data": {
"Get": {
"Article": [
{
"title": "Army builds new body armor 14-times stronger in the face of enemy fire"
},
...
]
}
}
}

Filter by property length​

Filtering can be performed with the length of properties.

The length of properties is calculated differently depending on the type:

  • array types: the number of entries in the array is used, where null (property not present) and empty arrays both have the length 0.
  • strings and texts: the number of characters, unicode characters such as δΈ– count as one character.
  • numbers, booleans, geo-coordinates, phone-numbers and data-blobs are not supported.
{
Get {
<Class>(where: {
operator: <Operator>,
valueInt: <value>
path: [len(<property>)]
}
}

Supported operators are (not) equal and greater/less than (equal) and values need to be 0 or larger.

note

Filtering by property length requires the target class to be configured to index the length. See here for details.

Multiple operands​

You can set multiple operands by providing an array.

For example, these filters select based on the class Article with a wordCount higher than 1000 and who are published before January 1st 2020.

tip

You can filter datetimes similarly to numbers, with the valueDate given as string in RFC3339 format.

import weaviate

client = weaviate.Client("http://localhost:8080")

where_filter = {
"operator": "And",
"operands": [{
"path": ["wordCount"],
"operator": "GreaterThan",
"valueInt": 1000
}, {
"path": ["title"],
"operator": "Like",
"valueText": "*economy*",
}]
}

response = (
client.query
.get("Article", "title")
.with_where(where_filter)
.do()
)

print(response)
Expected response
{
"data": {
"Get": {
"Article": [
{
"title": "China\u2019s long-distance lorry drivers are unsung heroes of its economy"
},
{
"title": "\u2018It\u2019s as if there\u2019s no Covid\u2019: Nepal defies pandemic amid a broken economy"
},
{
"title": "A tax hike threatens the health of Japan\u2019s economy"
}
]
}
}
}

Like operator​

Using the Like operator allows you to do string searches based on partial match. The capabilities of this operator are:

  • ? -> exactly one unknown character
    • car? matches cart, care, but not car
  • * -> zero, one or more unknown characters
    • car* matches car, care, carpet, etc
    • *car* matches car, healthcare, etc.
import weaviate

client = weaviate.Client("http://localhost:8080")

where_filter = {
"path": ["name"],
"operator": "Like",
"valueString": "New *"
}

query_result = (
client.query
.get("Publication", "name")
.with_where(where_filter)
.do()
)

print(query_result)

Notes​

Each query using the Like operator iterates over the entire inverted index for that property. The search time will go up linearly with the dataset size. Be aware that there might be a point where this query is too expensive and will not work anymore. We will improve this implementation in a future release. You can leave feedback or feature requests in a GitHub issue.

Expected response
{
"data": {
"Get": {
"Publication": [
{
"name": "The New York Times Company"
},
{
"name": "International New York Times"
},
{
"name": "New York Times"
},
{
"name": "New Yorker"
}
]
}
}
}

Beacon (reference) filters​

You can also search for the value of the property of a beacon.

For example, these filters select based on the class Article but who have inPublication set to New Yorker.

import weaviate

client = weaviate.Client("http://localhost:8080")

where_filter = {
"path": ["inPublication", "Publication", "name"],
"operator": "Equal",
"valueString": "New Yorker"
}

query_result = (
client.query
.get("Article", ["title", "inPublication{... on Publication{name}}"])
.with_where(where_filter)
.do()
)

print(query_result)
Expected response
{
"data": {
"Get": {
"Article": [
{
"inPublication": [
{
"name": "New Yorker"
}
],
"title": "The Hidden Costs of Automated Thinking"
},
{
"inPublication": [
{
"name": "New Yorker"
}
],
"title": "The Real Deal Behind the U.S.\u2013Iran Prisoner Swap"
},
...
]
}
}
}

Filter objects by count of reference​

Above example shows how filter by reference can solve straightforward questions like "Find all articles that are published by New Yorker". But questions like "Find all articles that are written by authors that wrote at least two articles", cannot be answered by the above query structure. It is however possible to filter by reference count. To do so, simply provide one of the existing compare operators (Equal, LessThan, LessThanEqual, GreaterThan, GreaterThanEqual) and use it directly on the reference element. For example:

import weaviate

client = weaviate.Client("http://localhost:8080")

where_filter = {
"valueInt": 2,
"operator": "GreaterThanEqual",
"path": ["writesFor"]
}

response = (
client.query
.get("Author", ["name", "writesFor {... on Publication { name }}"])
.with_where(where_filter)
.do()
)

print(query_result)
Expected response
{
"data": {
"Get": {
"Author": [
{
"name": "Agam Shah",
"writesFor": [
{
"name": "Wall Street Journal"
},
{
"name": "Wall Street Journal"
}
]
},
{
"name": "Costas Paris",
"writesFor": [
{
"name": "Wall Street Journal"
},
{
"name": "Wall Street Journal"
}
]
},
...
]
}
}
}

GeoCoordinates filter​

A special case of the Where filter is with geoCoordinates. This filter is only supported by the Get{} function. If you've set the geoCoordinates property type, you can search in an area based on kilometers.

For example, this curious returns all in a radius of 2KM around a specific geo-location:

import weaviate

client = weaviate.Client("http://localhost:8080")

get_articles_where = """
{
Get {
Publication(where: {
operator: WithinGeoRange,
valueGeoRange: {
geoCoordinates: {
latitude: 51.51, # latitude
longitude: -0.09 # longitude
},
distance: {
max: 2000 # distance in meters
}
},
path: ["headquartersGeoLocation"] # property needs to be of geoLocation type.
}) {
name
headquartersGeoLocation {
latitude
longitude
}
}
}
}
"""

query_result = client.query.raw(get_articles_where)
print(query_result)
Expected response
{
"data": {
"Get": {
"Publication": [
{
"headquartersGeoLocation": {
"latitude": 51.512737,
"longitude": -0.0962234
},
"name": "Financial Times"
},
{
"headquartersGeoLocation": {
"latitude": 51.512737,
"longitude": -0.0962234
},
"name": "International New York Times"
}
]
}
}
}

Filter by null state​

Using the IsNull operator allows you to do filter for objects where given properties are null or not null. Note that zero-length arrays and empty strings are equivalent to a null value.

{
Get {
<Class>(where: {
operator: IsNull,
valueBoolean: <true/false>
path: [<property>]
}
}
note

Filtering by null-state requires the target class to be configured to index this. See here for details.

More Resources​

If you can't find the answer to your question here, please look at the:

  1. Frequently Asked Questions. Or,
  2. Knowledge base of old issues. Or,
  3. For questions: Stackoverflow. Or,
  4. For more involved discussion: Weaviate Community Forum. Or,
  5. We also have a Slack channel.