Filter operators for collections (Go)

Many Data API commands, like Find documents (Go), accept a filter parameter to determine which documents to return or update. The filter parameter uses one or more filter operators.

You must use & to escape any . or & in field names in a filter. Dot notation, which is used to reference nested fields, should not be escaped. For more information, see Work with . and & in field names (Go).

Operators

You can use the following operators in a filter. All operators are case-sensitive.

Equal (default)

The $eq operator matches documents where the specified field is equal to the specified value.

This is the default when you do not specify an operator.

package main

import (
	"context"
	"fmt"
	"log"

	"github.com/datastax/astra-db-go/v2/astra"
	"github.com/datastax/astra-db-go/v2/astra/filter"
	"github.com/datastax/astra-db-go/v2/astra/options"
)

func main() {
	ctx := context.Background()

	// Get an existing collection
	client := astra.NewClient(
		options.API().SetEnvironment(options.EnvironmentHCD),
	)

	database := client.Database(
		"API_ENDPOINT",
		options.API().
			SetUsernamePasswordTokenProvider(
				"USERNAME",
				"PASSWORD",
			).
			SetKeyspace("KEYSPACE_NAME"),
	)

	collection := database.Collection("COLLECTION_NAME")

	// Find a document
	var result astra.Document
	err := collection.FindOne(ctx, filter.Eq("number_of_pages", 714)).
		Decode(&result)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println(result.ToMap())
}

Not equal

The $ne operator matches documents where the specified field is not equal to the specified value.

package main

import (
	"context"
	"fmt"
	"log"

	"github.com/datastax/astra-db-go/v2/astra"
	"github.com/datastax/astra-db-go/v2/astra/filter"
	"github.com/datastax/astra-db-go/v2/astra/options"
)

func main() {
	ctx := context.Background()

	// Get an existing collection
	client := astra.NewClient(
		options.API().SetEnvironment(options.EnvironmentHCD),
	)

	database := client.Database(
		"API_ENDPOINT",
		options.API().
			SetUsernamePasswordTokenProvider(
				"USERNAME",
				"PASSWORD",
			).
			SetKeyspace("KEYSPACE_NAME"),
	)

	collection := database.Collection("COLLECTION_NAME")

	// Find a document
	var result astra.Document
	err := collection.FindOne(ctx, filter.Ne("number_of_pages", 300)).
		Decode(&result)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println(result.ToMap())
}

Greater than

The $gt operator matches documents where the specified field is greater than the specified value.

package main

import (
	"context"
	"fmt"
	"log"

	"github.com/datastax/astra-db-go/v2/astra"
	"github.com/datastax/astra-db-go/v2/astra/filter"
	"github.com/datastax/astra-db-go/v2/astra/options"
)

func main() {
	ctx := context.Background()

	// Get an existing collection
	client := astra.NewClient(
		options.API().SetEnvironment(options.EnvironmentHCD),
	)

	database := client.Database(
		"API_ENDPOINT",
		options.API().
			SetUsernamePasswordTokenProvider(
				"USERNAME",
				"PASSWORD",
			).
			SetKeyspace("KEYSPACE_NAME"),
	)

	collection := database.Collection("COLLECTION_NAME")

	// Find a document
	var result astra.Document
	err := collection.FindOne(ctx, filter.Gt("number_of_pages", 300)).
		Decode(&result)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println(result.ToMap())
}

Greater than or equal

The $gte operator matches documents where the specified field is greater than or equal to the specified value.

package main

import (
	"context"
	"fmt"
	"log"

	"github.com/datastax/astra-db-go/v2/astra"
	"github.com/datastax/astra-db-go/v2/astra/filter"
	"github.com/datastax/astra-db-go/v2/astra/options"
)

func main() {
	ctx := context.Background()

	// Get an existing collection
	client := astra.NewClient(
		options.API().SetEnvironment(options.EnvironmentHCD),
	)

	database := client.Database(
		"API_ENDPOINT",
		options.API().
			SetUsernamePasswordTokenProvider(
				"USERNAME",
				"PASSWORD",
			).
			SetKeyspace("KEYSPACE_NAME"),
	)

	collection := database.Collection("COLLECTION_NAME")

	// Find a document
	var result astra.Document
	err := collection.FindOne(ctx, filter.Gte("number_of_pages", 300)).
		Decode(&result)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println(result.ToMap())
}

Less than

The $lt operator matches documents where the specified field is less than the specified value.

package main

import (
	"context"
	"fmt"
	"log"

	"github.com/datastax/astra-db-go/v2/astra"
	"github.com/datastax/astra-db-go/v2/astra/filter"
	"github.com/datastax/astra-db-go/v2/astra/options"
)

func main() {
	ctx := context.Background()

	// Get an existing collection
	client := astra.NewClient(
		options.API().SetEnvironment(options.EnvironmentHCD),
	)

	database := client.Database(
		"API_ENDPOINT",
		options.API().
			SetUsernamePasswordTokenProvider(
				"USERNAME",
				"PASSWORD",
			).
			SetKeyspace("KEYSPACE_NAME"),
	)

	collection := database.Collection("COLLECTION_NAME")

	// Find a document
	var result astra.Document
	err := collection.FindOne(ctx, filter.Lt("number_of_pages", 300)).
		Decode(&result)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println(result.ToMap())
}

Less than or equal

The $lte operator matches documents where the specified field is less than or equal to the specified value.

package main

import (
	"context"
	"fmt"
	"log"

	"github.com/datastax/astra-db-go/v2/astra"
	"github.com/datastax/astra-db-go/v2/astra/filter"
	"github.com/datastax/astra-db-go/v2/astra/options"
)

func main() {
	ctx := context.Background()

	// Get an existing collection
	client := astra.NewClient(
		options.API().SetEnvironment(options.EnvironmentHCD),
	)

	database := client.Database(
		"API_ENDPOINT",
		options.API().
			SetUsernamePasswordTokenProvider(
				"USERNAME",
				"PASSWORD",
			).
			SetKeyspace("KEYSPACE_NAME"),
	)

	collection := database.Collection("COLLECTION_NAME")

	// Find a document
	var result astra.Document
	err := collection.FindOne(ctx, filter.Lte("number_of_pages", 300)).
		Decode(&result)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println(result.ToMap())
}

In

The $in operator matches documents where the field contains any of the specified values. For fields that store an array, the operator matches documents where the array contains any of the specified values.

package main

import (
	"context"
	"fmt"
	"log"

	"github.com/datastax/astra-db-go/v2/astra"
	"github.com/datastax/astra-db-go/v2/astra/filter"
	"github.com/datastax/astra-db-go/v2/astra/options"
)

func main() {
	ctx := context.Background()

	// Get an existing collection
	client := astra.NewClient(
		options.API().SetEnvironment(options.EnvironmentHCD),
	)

	database := client.Database(
		"API_ENDPOINT",
		options.API().
			SetUsernamePasswordTokenProvider(
				"USERNAME",
				"PASSWORD",
			).
			SetKeyspace("KEYSPACE_NAME"),
	)

	collection := database.Collection("COLLECTION_NAME")

	// Find a document
	var result astra.Document
	err := collection.FindOne(ctx, filter.In("genres", "Fantasy", "Romance")).
		Decode(&result)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println(result.ToMap())
}

If you have only one value to match, you can use the single value instead of an array, like { "$in": "VALUE" }.

Not in

The $nin operator matches documents where the field doesn’t contain any of the specified values.

package main

import (
	"context"
	"fmt"
	"log"

	"github.com/datastax/astra-db-go/v2/astra"
	"github.com/datastax/astra-db-go/v2/astra/filter"
	"github.com/datastax/astra-db-go/v2/astra/options"
)

func main() {
	ctx := context.Background()

	// Get an existing collection
	client := astra.NewClient(
		options.API().SetEnvironment(options.EnvironmentHCD),
	)

	database := client.Database(
		"API_ENDPOINT",
		options.API().
			SetUsernamePasswordTokenProvider(
				"USERNAME",
				"PASSWORD",
			).
			SetKeyspace("KEYSPACE_NAME"),
	)

	collection := database.Collection("COLLECTION_NAME")

	// Find a document
	var result astra.Document
	err := collection.FindOne(
		ctx,
		filter.Nin("genres", "Fantasy", "Romance"),
	).Decode(&result)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println(result.ToMap())
}

Exists

The $exists operator matches documents that have the specified field, even if the field value is null.

package main

import (
	"context"
	"fmt"
	"log"

	"github.com/datastax/astra-db-go/v2/astra"
	"github.com/datastax/astra-db-go/v2/astra/filter"
	"github.com/datastax/astra-db-go/v2/astra/options"
)

func main() {
	ctx := context.Background()

	// Get an existing collection
	client := astra.NewClient(
		options.API().SetEnvironment(options.EnvironmentHCD),
	)

	database := client.Database(
		"API_ENDPOINT",
		options.API().
			SetUsernamePasswordTokenProvider(
				"USERNAME",
				"PASSWORD",
			).
			SetKeyspace("KEYSPACE_NAME"),
	)

	collection := database.Collection("COLLECTION_NAME")

	// Find a document
	var result astra.Document
	err := collection.FindOne(ctx, filter.Coll.Exists("borrower", true)).
		Decode(&result)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println(result.ToMap())
}

All

For fields that store an array, the $all operator matches documents where the array contains all of the specified values.

package main

import (
	"context"
	"fmt"
	"log"

	"github.com/datastax/astra-db-go/v2/astra"
	"github.com/datastax/astra-db-go/v2/astra/filter"
	"github.com/datastax/astra-db-go/v2/astra/options"
)

func main() {
	ctx := context.Background()

	// Get an existing collection
	client := astra.NewClient(
		options.API().SetEnvironment(options.EnvironmentHCD),
	)

	database := client.Database(
		"API_ENDPOINT",
		options.API().
			SetUsernamePasswordTokenProvider(
				"USERNAME",
				"PASSWORD",
			).
			SetKeyspace("KEYSPACE_NAME"),
	)

	collection := database.Collection("COLLECTION_NAME")

	// Find a document
	var result astra.Document
	err := collection.FindOne(
		ctx,
		filter.All("genres", "Fantasy", "Romance"),
	).Decode(&result)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println(result.ToMap())
}

Size

For fields that store an array, the $size operator matches documents where the array has the specified number of elements.

package main

import (
	"context"
	"fmt"
	"log"

	"github.com/datastax/astra-db-go/v2/astra"
	"github.com/datastax/astra-db-go/v2/astra/filter"
	"github.com/datastax/astra-db-go/v2/astra/options"
)

func main() {
	ctx := context.Background()

	// Get an existing collection
	client := astra.NewClient(
		options.API().SetEnvironment(options.EnvironmentHCD),
	)

	database := client.Database(
		"API_ENDPOINT",
		options.API().
			SetUsernamePasswordTokenProvider(
				"USERNAME",
				"PASSWORD",
			).
			SetKeyspace("KEYSPACE_NAME"),
	)

	collection := database.Collection("COLLECTION_NAME")

	// Find a document
	var result astra.Document
	err := collection.FindOne(ctx, filter.Coll.Size("genres", 3)).
		Decode(&result)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println(result.ToMap())
}

Not

The $not operator returns documents that don’t match the condition of the clause.

package main

import (
	"context"
	"fmt"
	"log"

	"github.com/datastax/astra-db-go/v2/astra"
	"github.com/datastax/astra-db-go/v2/astra/filter"
	"github.com/datastax/astra-db-go/v2/astra/options"
)

func main() {
	ctx := context.Background()

	// Get an existing collection
	client := astra.NewClient(
		options.API().SetEnvironment(options.EnvironmentHCD),
	)

	database := client.Database(
		"API_ENDPOINT",
		options.API().
			SetUsernamePasswordTokenProvider(
				"USERNAME",
				"PASSWORD",
			).
			SetKeyspace("KEYSPACE_NAME"),
	)

	collection := database.Collection("COLLECTION_NAME")

	// Find a document
	var result astra.Document
	err := collection.FindOne(
		ctx,
		filter.Coll.Not(filter.Eq("is_checked_out", false)),
	).Decode(&result)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println(result.ToMap())
}

Combine operators (And, Or)

The $and operator joins clauses with a logical AND. Only documents that match the conditions of all clauses are returned.

The $or operator joins clauses with a logical OR. Documents that match the condition of any of the clauses are returned.

You can use $and and $or separately or together. If you want to match multiple flexible conditions, use $and and $or together in the same filter:

package main

import (
	"context"
	"fmt"
	"log"

	"github.com/datastax/astra-db-go/v2/astra"
	"github.com/datastax/astra-db-go/v2/astra/filter"
	"github.com/datastax/astra-db-go/v2/astra/options"
)

func main() {
	ctx := context.Background()

	// Get an existing collection
	client := astra.NewClient(
		options.API().SetEnvironment(options.EnvironmentHCD),
	)

	database := client.Database(
		"API_ENDPOINT",
		options.API().
			SetUsernamePasswordTokenProvider(
				"USERNAME",
				"PASSWORD",
			).
			SetKeyspace("KEYSPACE_NAME"),
	)

	collection := database.Collection("COLLECTION_NAME")

	// Find a document
	var result astra.Document
	err := collection.FindOne(
		ctx,
		filter.And(
			filter.Or(
				filter.Eq("is_checked_out", false),
				filter.Lt("number_of_pages", 300),
			),
			filter.Or(
				filter.In("genres", "Fantasy", "Romance"),
				filter.Gte("publication_year", 2002),
			),
		),
	).Decode(&result)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println(result.ToMap())
}

To filter on a range of values, use $and with $lt/$lte and $gt/$gte:

package main

import (
	"context"
	"fmt"
	"log"

	"github.com/datastax/astra-db-go/v2/astra"
	"github.com/datastax/astra-db-go/v2/astra/filter"
	"github.com/datastax/astra-db-go/v2/astra/options"
)

func main() {
	ctx := context.Background()

	// Get an existing collection
	client := astra.NewClient(
		options.API().SetEnvironment(options.EnvironmentHCD),
	)

	database := client.Database(
		"API_ENDPOINT",
		options.API().
			SetUsernamePasswordTokenProvider(
				"USERNAME",
				"PASSWORD",
			).
			SetKeyspace("KEYSPACE_NAME"),
	)

	collection := database.Collection("COLLECTION_NAME")

	// Find a document
	var result astra.Document
	err := collection.FindOne(
		ctx,
		filter.And(
			filter.Lt("number_of_pages", 300),
			filter.Gte("number_of_pages", 200),
		),
	).Decode(&result)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println(result.ToMap())
}

Filter nested fields

Use dot notation to filter nested fields. For example, field.subfield.subsubfield.

package main

import (
	"context"
	"fmt"
	"log"

	"github.com/datastax/astra-db-go/v2/astra"
	"github.com/datastax/astra-db-go/v2/astra/filter"
	"github.com/datastax/astra-db-go/v2/astra/options"
)

func main() {
	ctx := context.Background()

	// Get an existing collection
	client := astra.NewClient(
		options.API().SetEnvironment(options.EnvironmentHCD),
	)

	database := client.Database(
		"API_ENDPOINT",
		options.API().
			SetUsernamePasswordTokenProvider(
				"USERNAME",
				"PASSWORD",
			).
			SetKeyspace("KEYSPACE_NAME"),
	)

	collection := database.Collection("COLLECTION_NAME")

	// Find a document
	var result astra.Document
	err := collection.FindOne(ctx, filter.Eq("metadata.language", "French")).
		Decode(&result)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println(result.ToMap())
}