Using Query Builder

When you need to execute some SQL query without all the ORM stuff involved, you can either compose the query yourself, or use the QueryBuilder helper to construct the query for you:

const qb = orm.em.createQueryBuilder(Author);
qb.update({ name: 'test 123', type: PublisherType.GLOBAL }).where({ id: 123, type: PublisherType.LOCAL });

console.log(qb.getQuery());
// update `publisher2` set `name` = ?, `type` = ? where `id` = ? and `type` = ?

console.log(qb.getParams());
// ['test 123', PublisherType.GLOBAL, 123, PublisherType.LOCAL]

// run the query
const res1 = await qb.execute();

QueryBuilder also supports smart query conditions.

Using Knex.js

Under the hood, QueryBuilder uses Knex.js to compose and run queries. You can access configured knex instance via qb.getKnexQuery() method:

const qb = orm.em.createQueryBuilder(Author);
qb.update({ name: 'test 123', type: PublisherType.GLOBAL }).where({ id: 123, type: PublisherType.LOCAL });
const knex = qb.getKnexQuery(); // instance of Knex' QueryBuilder

// do what ever you need with `knex`

const res = await orm.em.getConnection().execute(knex);
const entities = res.map(a => orm.em.map(Author, a));
console.log(entities); // Author[]

You can also get clear and configured knex instance from the connection via getKnex() method. As this method is not available on the base Connection class, you will need to either manually type cast the connection to AbstractSqlConnection (or the actual implementation you are using, e.g. MySqlConnection), or provide correct driver type hint to your EntityManager instance, which will be then automatically inferred in em.getConnection() method.

Driver and connection implementations are not directly exported from mikro-orm module. You can import them from mikro-orm/dist (e.g. import { PostgreSqlDriver } from 'mikro-orm/dist/drivers/PostgreSqlDriver').

const conn = orm.em.getConnection() as AbstractSqlConnection;
// you can make sure the `em` is correctly typed to `EntityManager<AbstractSqlDriver>`
// or one of its implementations:
// const em: EntityManager<AbstractSqlDriver> = orm.em;

const knex = conn.getKnex();

// do what ever you need with `knex`

const res = await knex;

Running Native SQL Query

You can run native SQL via underlying connection

const connection = orm.em.getConnection();
const res = await connection.execute('select 1 as count');
console.log(res); // res is array of objects: `[ { count: 1 } ]`

Executing the Query

You can use execute(method = 'all', mapResults = true)'s parameters to control form of result:

const res1 = await qb.execute('all'); // returns array of objects, default behavior
const res2 = await qb.execute('get'); // returns single object
const res3 = await qb.execute('run'); // returns object like `{ affectedRows: number, insertId: number, row: any }`

Second argument can be used to disable mapping of database columns to property names (which is enabled by default). In following example, Book entity has createdAt property defined with implicit underscored field name created_at:

const res4 = await orm.em.createQueryBuilder(Book).select('*').execute('get', true);
console.log(res4); // `createdAt` will be defined, while `created_at` will be missing
const res5 = await orm.em.createQueryBuilder(Book).select('*').execute('get', false);
console.log(res5); // `created_at` will be defined, while `createdAt` will be missing

To get entity instances from the QueryBuilder result, you can use getResult() and getSingleResult() methods:

const book = await orm.em.createQueryBuilder(Book).select('*').where({ id: 1 }).getSingleResult();
console.log(book instanceof Book); // true
const books = await orm.em.createQueryBuilder(Book).select('*').getResult();
console.log(books[0] instanceof Book); // true

Mapping Raw Results to Entities

Another way to create entity from raw results (that are not necessarily mapped to entity properties) is to use map() method of EntityManager, that is basically a shortcut for mapping results via IDatabaseDriver.mapResult() (which converts field names to property names - e.g. created_at to createdAt) and merge() which converts the data to entity instance and makes it managed.

This method comes handy when you want to use 3rd party query builders, where the result is not mapped to entity properties automatically:

const results = await knex.select('*').from('users').where(knex.raw('id = ?', [id]));
const users = results.map(user => orm.em.map(User, user));

// or use EntityRepository.map()
const repo = orm.em.getRepository(User);
const users = results.map(user => repo.map(user));

Implicit Joining

QueryBuilder supports automatic joining based on entity metadata:

const qb = orm.em.createQueryBuilder(BookTag, 't');
qb.select('*').where({ books: 123 });

console.log(qb.getQuery());
// select `t`.*, `e1`.`book_tag_id`, `e1`.`book_uuid_pk`
// from `book_tag` as `t`
// left join `book_to_book_tag` as `e1` ON `t`.`id` = `e1`.`book_tag_id`
// where `e1`.`book_uuid_pk` = ?

This also works for multiple levels of nesting:

const qb = orm.em.createQueryBuilder(Author);
qb.select('*')
  .where({ books: { tags: { name: 'Cool' } } })
  .orderBy({ books: { tags: { createdBy: QueryOrder.DESC } } });

console.log(qb.getQuery());
// select `e0`.*
// from `author` as `e0`
// left join `book2` as `e1` on `e0`.`id` = `e1`.`author_id`
// left join `book2_to_book_tag2` as `e3` on `e1`.`uuid_pk` = `e3`.`book2_uuid_pk`
// left join `book_tag2` as `e2` on `e3`.`book_tag2_id` = `e2`.`id`
// where `e2`.`name` = ?
// order by `e1`.`tags` asc

This is currently available only for filtering (where) and sorting (orderBy), only the root entity will be selected. To populate its relationships, you can use EntityLoader.

Explicit Joining

Another way is to manually specify join property via join()/leftJoin() methods:

const qb = orm.em.createQueryBuilder(BookTag, 't');
qb.select(['b.uuid', 'b.*', 't.*'], true)
  .join('t.books', 'b')
  .where({ 'b.title': 'test 123' })
  .limit(2, 1);

console.log(qb.getQuery());
// select distinct `b`.`uuid_pk`, `b`.*, `t`.*, `e1`.`book_tag_id`, `e1`.`book_uuid_pk` from `book_tag` as `t`
// join `book_to_book_tag` as `e1` ON `t`.`id` = `e1`.`book_tag_id`
// join `book` as `b` ON `e1`.`book_uuid_pk` = `b`.`uuid_pk`
// where `b`.`title` = ?
// limit ? offset ?

Complex Where Conditions

There are multiple ways to construct complex query conditions. You can either write parts of SQL manually, use andWhere()/orWhere(), or provide condition object:

Custom SQL in where

const qb = orm.em.createQueryBuilder(BookTag, 't');
qb.select(['b.*', 't.*'])
  .leftJoin('t.books', 'b')
  .where('b.title = ? or b.title = ?', ['test 123', 'lol 321'])
  .andWhere('1 = 1')
  .orWhere('1 = 2')
  .limit(2, 1);

console.log(qb.getQuery());
// select `b`.*, `t`.*, `e1`.`book_tag_id`, `e1`.`book_uuid_pk` from `book_tag` as `t`
// left join `book_to_book_tag` as `e1` ON `t`.`id` = `e1`.`book_tag_id`
// left join `book` as `b` ON `e1`.`book_uuid_pk` = `b`.`uuid_pk`
// where (((b.title = ? or b.title = ?) and (1 = 1)) or (1 = 2))
// limit ? offset ?

andWhere() and orWhere()

const qb = orm.em.createQueryBuilder(BookTag, 't');
qb.select(['b.*', 't.*'])
  .leftJoin('t.books', 'b')
  .where('b.title = ? or b.title = ?', ['test 123', 'lol 321'])
  .andWhere('1 = 1')
  .orWhere('1 = 2')
  .limit(2, 1);

console.log(qb.getQuery());
// select `b`.*, `t`.*, `e1`.`book_tag_id`, `e1`.`book_uuid_pk` from `book_tag` as `t`
// left join `book_to_book_tag` as `e1` ON `t`.`id` = `e1`.`book_tag_id`
// left join `book` as `b` ON `e1`.`book_uuid_pk` = `b`.`uuid_pk`
// where (((b.title = ? or b.title = ?) and (1 = 1)) or (1 = 2))
// limit ? offset ?

Conditions Object

const qb = orm.em.createQueryBuilder(Test);
qb.select('*').where({ $and: [{ id: { $nin: [3, 4] } }, { id: { $gt: 2 } }] });

console.log(qb.getQuery());
// select `e0`.* from `test` as `e0` where (`e0`.`id` not in (?, ?) and `e0`.`id` > ?)

Locking support

const qb = orm.em.createQueryBuilder(Test);
qb.select('*').where({ name: 'Lol 321' }).setLockMode(LockMode.PESSIMISTIC_READ);

console.log(qb.getQuery()); // for MySQL
// select `e0`.* from `test` as `e0` where `e0`.`name` = ? lock in share mode

QueryBuilder API

QueryBuilder provides fluent interface with these methods:

qb.select(fields: string | string[], distinct?: boolean): QueryBuilder;
qb.addSelect(fields: string | string[]): QueryBuilder;
qb.insert(data: Record<string, any>): QueryBuilder;
qb.update(data: Record<string, any>): QueryBuilder;
qb.delete(cond: Record<string, any>): QueryBuilder;
qb.count(fields: string | string[], distinct?: boolean): QueryBuilder;
qb.join(field: string, alias?: string): QueryBuilder;
qb.leftJoin(field: string, alias?: string): QueryBuilder;
qb.where(cond: Record<string, any>, operator?: '$and' | '$or'): QueryBuilder;
qb.andWhere(cond: Record<string, any>): QueryBuilder;
qb.orWhere(cond: Record<string, any>): QueryBuilder;
qb.groupBy(fields: string | string[]): QueryBuilder;
qb.having(cond: Record<string, any>): QueryBuilder;
qb.limit(limit: number, offset?: number): QueryBuilder;
qb.offset(offset: number): QueryBuilder;
qb.withSchema(schema?: string): QueryBuilder;
qb.execute<T>(method: 'all' | 'get' | 'run' = 'all', mapResults = true): T;
qb.getResult<T>(): T[];
qb.getSingleResult<T>(): T;
qb.setLockMode(mode: LockMode): QueryBuilder;
qb.getQuery(): string;
qb.getParams(): any[];
qb.clone(): QueryBuilder;