Using Query Builder

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Since v4, we need to make sure we are working with correctly typed EntityManager or EntityRepository to have access to createQueryBuilder() method.

import { EntityManager, EntityRepository } from '@mikro-orm/mysql'; // or any other driver package

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:

// since v5 we can also use `em.qb()` shortcut
const qb = 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.

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 em.createQueryBuilder(Book).select('*').execute('get', true);
console.log(res4); // `createdAt` will be defined, while `created_at` will be missing
const res5 = await 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 em.createQueryBuilder(Book).select('*').where({ id: 1 }).getSingleResult();
console.log(book instanceof Book); // true
const books = await em.createQueryBuilder(Book).select('*').getResult();
console.log(books[0] instanceof Book); // true

You can also use qb.getResultList() which is alias to qb.getResult().

Awaiting the QueryBuilder

Since v5 we can await the QueryBuilder instance, which will automatically execute the QB and return appropriate response. The QB instance is now typed based on usage of select/insert/update/delete/truncate methods to one of:

• SelectQueryBuilder
  • awaiting yields array of entities (as qb.getResultList())
• CountQueryBuilder
  • awaiting yields number (as qb.getCount())
• InsertQueryBuilder (extends RunQueryBuilder)
  • awaiting yields QueryResult
• UpdateQueryBuilder (extends RunQueryBuilder)
  • awaiting yields QueryResult
• DeleteQueryBuilder (extends RunQueryBuilder)
  • awaiting yields QueryResult
• TruncateQueryBuilder (extends RunQueryBuilder)
  • awaiting yields QueryResult

const res1 = await em.qb(Publisher).insert({
  name: 'p1',
  type: PublisherType.GLOBAL,
});
// res1 is of type `QueryResult<Publisher>`
console.log(res1.insertId);

const res2 = await em.qb(Publisher)
  .select('*')
  .where({ name: 'p1' })
  .limit(5);
// res2 is Publisher[]
console.log(res2.map(p => p.name));

const res3 = await em.qb(Publisher).count().where({ name: 'p1' });
// res3 is number
console.log(res3 > 0); // true

const res4 = await em.qb(Publisher)
  .update({ type: PublisherType.LOCAL })
  .where({ name: 'p1' });
// res4 is QueryResult<Publisher>
console.log(res4.affectedRows > 0); // true

const res5 = await em.qb(Publisher).delete().where({ name: 'p1' });
// res5 is QueryResult<Publisher>
console.log(res5.affectedRows > 0); // true
expect(res5.affectedRows > 0).toBe(true); // test the type

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 => em.map(User, user));

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

Implicit Joining

QueryBuilder supports automatic joining based on entity metadata:

const qb = 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 = 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 em.populate(). If your populated references are not wrapped (methods like .unwrap() are undefined, make sure that property was defined with { wrappedEntity: true } as described in Defining Entities.

Explicit Joining

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

const qb = 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 ?

Mapping joined results

To select multiple entities and map them from QueryBuilder, we can use joinAndSelect or leftJoinAndSelect method:

// `res` will contain array of authors, with books and their tags populated
const res = await em.createQueryBuilder(Author, 'a')
  .select('*')
  .leftJoinAndSelect('a.books', 'b')
  .leftJoinAndSelect('b.tags', 't')
  .where({ 't.name': ['sick', 'sexy'] })
  .getResultList();

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:

Using custom SQL fragments

It is possible to use any SQL fragment in your WHERE query or ORDER BY clause:

const users = em.createQueryBuilder(User)
  .select('*')
  .where({ 'lower(email)': 'foo@bar.baz' })
  .orderBy({ [`(point(loc_latitude, loc_longitude) <@> point(0, 0))`]: 'ASC' })
  .getResultList();

This will produce following query:

select `e0`.*
from `user` as `e0`
where lower(email) = 'foo@bar.baz'
order by (point(loc_latitude, loc_longitude) <@> point(0, 0)) asc

Custom SQL in where

const qb = 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 = 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 = 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` > ?)

Count queries

To create a count query, we can use qb.count(), which will initialize a select clause with count() function. By default, it will use the primary key.

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

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

// to get the count, we can use `qb.execute()`
const res = await qb.execute('get');
const count = res ? +res.count : 0;

To simplify this process, we can use qb.getCount() method. Following code is equivalent:

const qb = em.createQueryBuilder(Test);
qb.select('*').limit(10, 20).where({ $and: [{ id: { $nin: [3, 4] } }, { id: { $gt: 2 } }] });

const count = await qb.getCount();

This will also remove any existing limit and offset from the query (the QB will be cloned under the hood, so calling getCount() does not mutate the original QB state).

Pagination

If we want to paginate the results of a QueryBuilder, we can use qb.getResultAndCount() method. It returns an ordered tuple, the first item being an array of results, and the second one being the total count of items, discarding the limit and offset clause.

const qb = em.createQueryBuilder(User);
qb.select('*')
  .where({ age: 18 })
  .limit(10);
const [results, count] = await qb.getResultAndCount();

console.log(results.length); // max 10, as we used the limit clause
console.log(count); // total count regardless limit and offset, e.g. 1327

Overriding FROM clause

You can specify the table used in the FROM clause, replacing the current table name if one has already been specified. This is typically used to specify a sub-query expression in SQL.

const qb = em.createQueryBuilder(Book2);
qb.select('*').from(Author2).where({ id: { $gt: 2 } });

console.log(qb.getQuery());
// select `e0`.* from `author2` as `e0` where `e0`.`id` > 2;

You can also use sub-queries in the FROM like this:

const qb1 = em.createQueryBuilder(Book2).where({ id: { $lte: new Date() } }).orderBy({ id: 'DESC' }).limit(10);
const qb2 = em.createQueryBuilder(qb1.clone())
qb2.select('*').orderBy({ id: 'ASC' });

console.log(qb2.getQuery());
// select `e1`.* from (select `e0`.* from `book2` as `e0` where `e0`.`id` <= ? order by `e0`.`id` desc limit ?) as `e1` order by `e1`.`id`;

To set up an alias to refer to a table in a SELECT statement, pass the second argument as follows:

const qb1 = em.createQueryBuilder(Book2, 'b1').where({ id: { $lte: new Date() } }).orderBy({ id: 'DESC' }).limit(10);
const qb2 = em.createQueryBuilder(qb1.clone(), 'b2')
qb2.select('*').orderBy({ id: 'ASC' });

console.log(qb2.getQuery());
// select `b2`.* from (select `b1`.* from `book2` as `b1` where `b1`.`id` <= ? order by `b1`.`id` desc limit ?) as `b2` order by `b2`.`id`;

Using sub-queries

You can filter using sub-queries in where conditions:

const qb1 = em.createQueryBuilder(Book2, 'b').select('b.author').where({ price: { $gt: 100 } });
const qb2 = em.createQueryBuilder(Author2, 'a').select('*').where({ id: { $in: qb1.getKnexQuery() } });

console.log(qb2.getQuery());
// select `a`.* from `author2` as `a` where `a`.`id` in (select `b`.`author_id` from `book2` as `b` where `b`.`price` > ?)

For sub-queries in selects, use the qb.as(alias) method:

The dynamic property (booksTotal) needs to be defined at the entity level (as persist: false).

const knex = em.getKnex();
const qb1 = em.createQueryBuilder(Book2, 'b').count('b.uuid', true).where({ author: knex.ref('a.id') }).as('Author2.booksTotal');
const qb2 = em.createQueryBuilder(Author2, 'a');
qb2.select(['*', qb1]).orderBy({ booksTotal: 'desc' });

console.log(qb2.getQuery());
// select `a`.*, (select count(distinct `b`.`uuid_pk`) as `count` from `book2` as `b` where `b`.`author_id` = `a`.`id`) as `books_total` from `author2` as `a` order by `books_total` desc

const knex = em.getKnex();
const qb3 = em.createQueryBuilder(Book2, 'b').count('b.uuid', true).where({ author: knex.ref('a.id') }).as('books_total');
const qb4 = em.createQueryBuilder(Author2, 'a');
qb4.select(['*', qb3]).orderBy({ booksTotal: 'desc' });

console.log(qb4.getQuery());
// select `a`.*, (select count(distinct `b`.`uuid_pk`) as `count` from `book2` as `b` where `b`.`author_id` = `a`.`id`) as `books_total` from `author2` as `a` order by `books_total` desc

When you want to filter by sub-query on the left-hand side of a predicate, you will need to register it first via qb.withSubquery():

The dynamic property (booksTotal) needs to be defined at the entity level (as persist: false). You always need to use prefix in the qb.withSchema() (so a.booksTotal).

const knex = em.getKnex();
const qb1 = em.createQueryBuilder(Book2, 'b').count('b.uuid', true).where({ author: knex.ref('a.id') }).getKnexQuery();
const qb2 = em.createQueryBuilder(Author2, 'a');
qb2.select('*').withSubQuery(qb1, 'a.booksTotal').where({ 'a.booksTotal': { $in: [1, 2, 3] } });

console.log(qb2.getQuery());
// select `a`.* from `author2` as `a` where (select count(distinct `b`.`uuid_pk`) as `count` from `book2` as `b` where `b`.`author_id` = `a`.`id`) in (?, ?, ?)

const knex = em.getKnex();
const qb3 = em.createQueryBuilder(Book2, 'b').count('b.uuid', true).where({ author: knex.ref('a.id') }).getKnexQuery();
const qb4 = em.createQueryBuilder(Author2, 'a');
qb4.select('*').withSubQuery(qb3, 'a.booksTotal').where({ 'a.booksTotal': 1 });

console.log(qb4.getQuery());
// select `a`.* from `author2` as `a` where (select count(distinct `b`.`uuid_pk`) as `count` from `book2` as `b` where `b`.`author_id` = `a`.`id`) = ?

Referring to column in update queries

You can use qb.raw() to insert raw SQL snippets like this:

const qb = em.createQueryBuilder(Book);
qb.update({ price: qb.raw('price + 1') }).where({ uuid: '123' });

console.log(qb.getQuery());
// update `book` set `price` = price + 1 where `uuid_pk` = ?

Locking support

We can set the LockMode via qb.setLockMode().

const qb = 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

Available lock modes:

Mode	Postgres	MySQL
LockMode.PESSIMISTIC_READ	for share	lock in share mode
LockMode.PESSIMISTIC_WRITE	for update	for update
LockMode.PESSIMISTIC_PARTIAL_WRITE	for update skip locked	for update skip locked
LockMode.PESSIMISTIC_WRITE_OR_FAIL	for update nowait	for update nowait
LockMode.PESSIMISTIC_PARTIAL_READ	for share skip locked	lock in share mode skip locked
LockMode.PESSIMISTIC_READ_OR_FAIL	for share nowait	lock in share mode nowait

Optionally we can also pass list of table aliases we want to lock via second parameter:

const qb = em.createQueryBuilder(User, 'u');
qb.select('*')
  .leftJoinAndSelect('u.identities', 'i')
  .where({ name: 'Jon' })
  .setLockMode(LockMode.PESSIMISTIC_READ, ['u']);

console.log(qb.getQuery()); // for Postgres
// select ...
//   from "user" as "u"
//   left join "identity" as "i" on "u"."id" = "i"."user_id"
//   where "u"."name" = 'Jon'
//   for update of "u" skip locked

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 = 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 em.getConnection().execute(knex);
const entities = res.map(a => 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/core module. You can import them from the driver packages (e.g. import { PostgreSqlDriver } from '@mikro-orm/postgresql').

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

Since v4 we can also use em.execute() which will also handle logging and mapping of exceptions.