Query()

This operation retrieves entities that match a boolean filter expression.

func (c *Client) Query(ctx context.Context, option QueryOption, callOptions ...grpc.CallOption) (ResultSet, error)

Request Syntax

option := milvusclient.NewQueryOption(collectionName).
    WithFilter(expr).
    WithTemplateParam(key, val).
    WithOffset(offset).
    WithLimit(limit).
    WithOutputFields(fieldNames).
    WithConsistencyLevel(consistencyLevel).
    WithPartitions(partitionNames).
    WithIDs(ids)

result, err := client.Query(ctx, option)

PARAMETERS:

• collectionName (string)

  The name of the target collection.

OPTION METHODS:

• WithFilter(expr string)

  Applies a boolean filter expression to narrow results.

• WithTemplateParam(key string, val any)

  Sets a template parameter for expression evaluation.

• WithOffset(offset int)

  Sets the number of results to skip before returning matches.

• WithLimit(limit int)

  Sets the maximum number of results to return.

• WithOutputFields(fieldNames ...string)

  Specifies which fields to include in the returned results.

• WithConsistencyLevel(consistencyLevel [entity.ConsistencyLevel](../Collection/ConsistencyLevel.md))

  Sets the consistency level for the operation (Strong, Bounded, Session, or Eventually).

• WithPartitions(partitionNames ...string)

  Limits the operation to the specified partitions.

• WithIDs(ids column.Column)

  Sets the i ds for the operation.

RETURN TYPE:

ResultSet, error

RETURNS:

The search or query results containing matched entities with scores and fields. Returns an error if the operation fails.

EXCEPTIONS:

• error

  Check err != nil for failure details.

Example

import (
    "context"
    "fmt"
    "log"

    "github.com/milvus-io/milvus/client/v2/milvusclient"
)

ctx, cancel := context.WithCancel(context.Background())
defer cancel()

milvusAddr := "127.0.0.1:19530"

cli, err := milvusclient.New(ctx, &milvusclient.ClientConfig{
    Address: milvusAddr,
})
if err != nil {
    log.Fatal("failed to connect to milvus server: ", err.Error())
}

defer cli.Close(ctx)

rs, err := cli.Query(ctx, milvusclient.NewQueryOption("quick_setup").
    WithFilter("emb_type == 3").
    WithOutputFields("id", "emb_type"))
if err != nil {
    // handle error
}

fmt.Println(rs.GetColumn("id"))