feat(query-builder): allow partial loading via `qb.(left/inner)JoinAn…

…dSelect()`

Closes #4364

packages/knex/src/query/QueryBuilder.ts

@@ -208,13 +208,13 @@ export class QueryBuilder<T extends object = AnyEntity> {
     return this.join(field, alias, cond, 'leftJoin');
   }
 
-  joinAndSelect(field: string, alias: string, cond: QBFilterQuery = {}, type: 'leftJoin' | 'innerJoin' | 'pivotJoin' = 'innerJoin', path?: string): SelectQueryBuilder<T> {
+  joinAndSelect(field: string, alias: string, cond: QBFilterQuery = {}, type: 'leftJoin' | 'innerJoin' | 'pivotJoin' = 'innerJoin', path?: string, fields?: string[]): SelectQueryBuilder<T> {
     if (!this.type) {
       this.select('*');
     }
 
     const prop = this.joinReference(field, alias, cond, type, path);
-    this.addSelect(this.getFieldsForJoinedLoad<T>(prop, alias));
+    this.addSelect(this.getFieldsForJoinedLoad<T>(prop, alias, fields));
     const [fromAlias] = this.helper.splitField(field);
     const populate = this._joinedProps.get(fromAlias);
     const item = { field: prop.name, strategy: LoadStrategy.JOINED, children: [] };
@@ -230,14 +230,18 @@ export class QueryBuilder<T extends object = AnyEntity> {
     return this as SelectQueryBuilder<T>;
   }
 
-  leftJoinAndSelect(field: string, alias: string, cond: QBFilterQuery = {}): SelectQueryBuilder<T> {
-    return this.joinAndSelect(field, alias, cond, 'leftJoin');
+  leftJoinAndSelect(field: string, alias: string, cond: QBFilterQuery = {}, fields: string[]): SelectQueryBuilder<T> {
+    return this.joinAndSelect(field, alias, cond, 'leftJoin', undefined, fields);
   }
 
-  protected getFieldsForJoinedLoad<U extends object>(prop: EntityProperty<U>, alias: string): Field<U>[] {
+  innerJoinAndSelect(field: string, alias: string, cond: QBFilterQuery = {}, fields: string[]): SelectQueryBuilder<T> {
+    return this.joinAndSelect(field, alias, cond, 'innerJoin', undefined, fields);
+  }
+
+  protected getFieldsForJoinedLoad<U extends object>(prop: EntityProperty<U>, alias: string, explicitFields?: string[]): Field<U>[] {
     const fields: Field<U>[] = [];
     prop.targetMeta!.props
-      .filter(prop => this.platform.shouldHaveColumn(prop, this._populate))
+      .filter(prop => explicitFields ? explicitFields.includes(prop.name) || prop.primary : this.platform.shouldHaveColumn(prop, this._populate))
       .forEach(prop => fields.push(...this.driver.mapPropToFieldNames<U>(this as unknown as QueryBuilder<U>, prop, alias)));
 
     return fields;

packages/knex/src/typings.ts

@@ -132,7 +132,8 @@ export interface IQueryBuilder<T> {
   join(field: string, alias: string, cond?: QBFilterQuery, type?: 'leftJoin' | 'innerJoin' | 'pivotJoin', path?: string): this;
   leftJoin(field: string, alias: string, cond?: QBFilterQuery): this;
   joinAndSelect(field: string, alias: string, cond?: QBFilterQuery): this;
-  leftJoinAndSelect(field: string, alias: string, cond?: QBFilterQuery): this;
+  leftJoinAndSelect(field: string, alias: string, cond?: QBFilterQuery, fields?: string[]): this;
+  innerJoinAndSelect(field: string, alias: string, cond?: QBFilterQuery, fields?: string[]): this;
   withSubQuery(subQuery: Knex.QueryBuilder, alias: string): this;
   where(cond: QBFilterQuery<T>, operator?: keyof typeof GroupOperator): this;
   where(cond: string, params?: any[], operator?: keyof typeof GroupOperator): this;

tests/features/partial-loading/partial-loading.mysql.test.ts

@@ -91,6 +91,23 @@ describe('partial loading (mysql)', () => {
     orm.em.clear();
     mock.mock.calls.length = 0;
 
+    // partial loading with query builder
+    const r3 = await orm.em.qb(Author2, 'a')
+      .select('id')
+      .innerJoinAndSelect('a.books', 'b', {}, ['author', 'title'])
+      .where({ id: god.id })
+      .orderBy({ 'b.title': 1 });
+    expect(r3).toHaveLength(1);
+    expect(r3[0].id).toBe(god.id);
+    expect(r3[0].name).toBeUndefined();
+    expect(r3[0].books[0].uuid).toBe(god.books[0].uuid);
+    expect(r3[0].books[0].title).toBe('Bible 1');
+    expect(r3[0].books[0].price).toBeUndefined();
+    expect(r3[0].books[0].author).toBeDefined();
+    expect(mock.mock.calls[0][0]).toMatch('select `a`.`id`, `b`.`uuid_pk` as `b__uuid_pk`, `b`.`title` as `b__title`, `b`.`author_id` as `b__author_id` from `author2` as `a` inner join `book2` as `b` on `a`.`id` = `b`.`author_id` where `a`.`id` = ? order by `b`.`title` asc');
+    orm.em.clear();
+    mock.mock.calls.length = 0;
+
     // when populating collections, the owner is selected automatically (here book.author)
     const r00 = await orm.em.find(Author2, god, { fields: ['id', 'books.title'] });
     expect(r00).toHaveLength(1);