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Query<R, J>

The Query class provides a configurable interface for executing raw SurrealQL statements with support for streaming, batch processing, and response handling. It extends Promise, allowing you to await it directly or use specialized methods.

Returned by: SurrealQueryable.query()

Source: query/query.ts

Type Parameters

  • R extends unknown[] - Array of result types for each query statement

  • J extends boolean - Boolean indicating if result is JSON (default: false)

Methods

.collect()

Collect and return the results of all queries at once. If any query fails, the promise rejects.

You can optionally specify which query indexes to collect.

Method Syntax

query.collect<T>(...queryIndexes?)

Parameters

ParameterTypeDescription
queryIndexes number[]Specific query indexes to collect. If omitted, collects all.

Type Parameters

  • T extends unknown[] - Override result types

Returns

Promise<Collect<T, J>> - Array of results

Examples

Single Query

const result = await db.query('SELECT * FROM users').collect();
console.log(result); // [{ success: true, result: [...] }]

Multiple Queries with Types

const [users, posts] = await db.query<[User[], Post[]]>(`
    SELECT * FROM users;
    SELECT * FROM posts;
`).collect();

Collect Specific Queries

const [users] = await db.query(`
    SELECT * FROM users;
    SELECT * FROM posts;
    SELECT * FROM comments;
`).collect<[User[]]>(0); // Only collect first query

With Bindings

const result = await db.query(
    'SELECT * FROM users WHERE age > $age',
    { age: 18 }
).collect();

.stream()

Stream response frames as they are received from the database.

Each iteration yields a value frame, error frame, or done frame.

Method Syntax

query.stream()

Returns

AsyncIterableIterator<Frame<unknown, J>> - Async iterator of frames

Each frame is one of three types, distinguished by the type property:

Value Frame (type: 'value')

  • frame.value - The result data

  • frame.query - Query index

Error Frame (type: 'error')

  • frame.error - Error information

  • frame.query - Query index

Done Frame (type: 'done')

  • frame.query - Query index that completed

Examples

Stream Processing

for await (const frame of db.query('SELECT * FROM users').stream()) {
    if (frame.type === 'value') {
        console.log('Received data:', frame.value);
    } else if (frame.type === 'error') {
        console.error('Query error:', frame.error);
    } else if (frame.type === 'done') {
        console.log('Query complete');
    }
}

Process Large Results

let count = 0;
for await (const frame of db.query('SELECT * FROM large_table').stream()) {
    if (frame.type === 'value') {
        await processRecord(frame.value);
        count++;
    }
}
console.log(`Processed ${count} records`);

.responses()

Get individual response objects for each query statement, including success/failure status.

Method Syntax

query.responses<T>()

Type Parameters

  • T extends unknown[] - Override result types

Returns

Promise<Responses<T, J>> - Array of QueryResponse objects

Examples

Handle Individual Responses

const responses = await db.query(`
    SELECT * FROM users;
    INVALID QUERY;
    SELECT * FROM posts;
`).responses();

for (const [index, response] of responses.entries()) {
    if (response.success) {
        console.log(`Query ${index} succeeded:`, response.result);
    } else {
        console.error(`Query ${index} failed:`, response.error.message);
    }
}

Check Query Statistics

const responses = await db.query('SELECT * FROM users').responses();

for (const response of responses) {
    if (response.success && response.stats) {
        console.log('Records scanned:', response.stats.recordsScanned);
        console.log('Duration:', response.stats.duration);
    }
}

.json()

Configure the query to return results as JSON strings.

Method Syntax

query.json()

Returns

Query<R, true> - Query returning JSON strings

Example

const jsonResults = await db.query('SELECT * FROM users').json().collect();
console.log(typeof jsonResults[0]); // 'string'

Complete Examples

Basic Query Execution

import { Surreal } from 'surrealdb';

const db = new Surreal();
await db.connect('ws://localhost:8000');

// Simple query
const result = await db.query('SELECT * FROM users').collect();
console.log(result[0]); // Array of users

// With await (same as .collect())
const result = await db.query('SELECT * FROM users');

Parameterized Queries

// Using bindings object
const result = await db.query(
    'SELECT * FROM users WHERE age > $age AND status = $status',
    { age: 18, status: 'active' }
).collect();

// Using surql template
import { surql } from 'surrealdb';

const minAge = 18;
const result = await db.query(
    surql`SELECT * FROM users WHERE age > ${minAge}`
).collect();

Multiple Statements

const [users, posts, comments] = await db.query<[User[], Post[], Comment[]]>(`
    SELECT * FROM users;
    SELECT * FROM posts WHERE published = true;
    SELECT * FROM comments WHERE approved = true;
`).collect();

console.log('Users:', users);
console.log('Posts:', posts);
console.log('Comments:', comments);

Streaming Large Results

const query = db.query('SELECT * FROM large_table');

for await (const frame of query.stream()) {
    if (frame.type === 'value') {
        // Process each chunk as it arrives
        await processChunk(frame.value);
    } else if (frame.type === 'error') {
        console.error('Error:', frame.error);
        break;
    }
}

Error Handling with Responses

const responses = await db.query(`
    CREATE users:john SET name = 'John';
    CREATE users:john SET name = 'Duplicate';
    SELECT * FROM users:john;
`).responses();

for (const [i, response] of responses.entries()) {
    if (response.success) {
        console.log(`Query ${i} OK:`, response.result);
    } else {
        console.log(`Query ${i} failed:`, response.error.message);
    }
}

Transaction Queries

const txn = await db.beginTransaction();

try {
    const [created, updated] = await txn.query<[User, User]>(`
        CREATE users:new SET name = 'New User';
        UPDATE users:john SET updated_at = time::now();
    `).collect();
    
    await txn.commit();
} catch (error) {
    await txn.cancel();
}

Complex Query with Statistics

const responses = await db.query(`
    SELECT * FROM users WHERE age > 18;
    SELECT count() FROM users GROUP BY status;
`).responses();

for (const response of responses) {
    if (response.success && response.stats) {
        console.log('Execution time:', response.stats.duration);
        console.log('Records scanned:', response.stats.recordsScanned);
        console.log('Bytes received:', response.stats.bytesReceived);
    }
}

Conditional Logic

const status = 'active';
const minAge = 18;

const result = await db.query(
    surql`
        LET $active_users = SELECT * FROM users WHERE status = ${status};
        LET $adult_users = SELECT * FROM users WHERE age >= ${minAge};
        RETURN {
            active: $active_users,
            adults: $adult_users,
            both: SELECT * FROM $active_users WHERE age >= ${minAge}
        };
    `
).collect();

Data Migration

// Batch update with query
const migration = await db.query(`
    -- Add new field to all users
    UPDATE users SET new_field = 'default_value';
    
    -- Migrate data format
    UPDATE users SET profile = {
        bio: bio,
        avatar: avatar_url
    };
    
    -- Remove old fields
    UPDATE users UNSET bio, avatar_url;
`).collect();

console.log('Migration complete');

Streaming with Progress

let totalRecords = 0;
let queriesCompleted = 0;

for await (const frame of db.query('SELECT * FROM users; SELECT * FROM posts;').stream()) {
    if (frame.type === 'value') {
        totalRecords += frame.value.length;
        console.log(`Received ${frame.value.length} records`);
    } else if (frame.type === 'done') {
        queriesCompleted++;
        console.log(`Query ${frame.query} completed`);
    }
}

console.log(`Total: ${totalRecords} records from ${queriesCompleted} queries`);

Best Practices

1. Use Parameterization

// Good: Parameterized
const result = await db.query(
    'SELECT * FROM users WHERE name = $name',
    { name: userName }
).collect();

// Better: Use surql template
const result = await db.query(
    surql`SELECT * FROM users WHERE name = ${userName}`
).collect();

// Avoid: String concatenation (SQL injection risk)
const result = await db.query(
    `SELECT * FROM users WHERE name = '${userName}'`
).collect();

2. Handle Errors Appropriately

// Good: Check individual responses
const responses = await db.query(multiStatementQuery).responses();

for (const response of responses) {
    if (!response.success) {
        handleError(response.error);
    }
}

// Simple: Use collect with try-catch
try {
    const results = await db.query(query).collect();
} catch (error) {
    // First error stops execution
}

3. Use Streaming for Large Results

// Good: Stream large datasets
for await (const frame of db.query('SELECT * FROM large_table').stream()) {
    if (frame.type === 'value') {
        await processChunk(frame.value);
    }
}

// Avoid: Loading everything into memory
const [large] = await db.query('SELECT * FROM large_table').collect();
// May cause memory issues

4. Leverage Type Parameters

// Good: Type-safe results
const [users, posts] = await db.query<[User[], Post[]]>(`
    SELECT * FROM users;
    SELECT * FROM posts;
`).collect();

// Now TypeScript knows the types
users[0].name; // string
posts[0].title; // string

See Also

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