[Solved] Find the mistake in this QueryBuilder code snippet:const result = await this.productRepository.createQueryBuilder('product') .select('product.name') .addSelect('product.price') .where('product.... | NestJS

NestJS - Database with TypeORM

Find the mistake in this QueryBuilder code snippet:

const result = await this.productRepository.createQueryBuilder('product')
  .select('product.name')
  .addSelect('product.price')
  .where('product.category = :cat', { cat: 'electronics' })
  .getOne();

AMissing alias in select() method

BgetOne() returns only one record, but query may match many

CaddSelect() cannot be used after select()

DParameters object is incorrectly formatted

Step-by-Step Solution

Solution:

Step 1: Understand getOne() behavior
getOne() returns a single record or null.
Step 2: Analyze query filter
Filter may match multiple products, so getOne() may not be appropriate.
Final Answer:
getOne() returns only one record, but query may match many -> Option B
Quick Check:
Use getMany() for multiple results, getOne() for single [OK]

Quick Trick: Use getMany() for multiple results, getOne() for single [OK]

Common Mistakes:

Assuming getOne() returns array
Thinking addSelect() is invalid after select()
Misunderstanding parameter object format

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More NestJS Quizzes

Find the mistake in this QueryBuilder code snippet:

Step 1: Understand getOne() behavior

Step 2: Analyze query filter

Final Answer:

Quick Check:

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