[Solved] This query code returns no items even though the table has matching data:const params = { TableName: 'Employees', KeyConditionExpression:... console.log(data.Items.length);What is the error? | AWS

AWS - DynamoDB

This query code returns no items even though the table has matching data:

const params = {
  TableName: 'Employees',
  KeyConditionExpression: 'EmployeeId = :id',
  ExpressionAttributeValues: { ':id': 'E123' }
};
const data = await client.query(params);
console.log(data.Items.length);

What is the error?

ATableName is misspelled

BKeyConditionExpression syntax is incorrect

CQuery requires ScanIndexForward parameter

DExpressionAttributeValues values must be wrapped with DynamoDB types

Step-by-Step Solution

Solution:

Step 1: Check ExpressionAttributeValues format
Values must be wrapped with DynamoDB types like { S: 'E123' }.
Step 2: Identify cause of no results
Without type wrappers, the query does not match any items, returning zero results.
Final Answer:
ExpressionAttributeValues values must be wrapped with DynamoDB types -> Option D
Quick Check:
Query values need DynamoDB type wrappers [OK]

Quick Trick: Always wrap query values with DynamoDB types like { S: 'value' } [OK]

Common Mistakes:

MISTAKES

Using raw string instead of typed value
Assuming ScanIndexForward is required
Ignoring case sensitivity in keys

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This query code returns no items even though the table has matching data:

Step 1: Check ExpressionAttributeValues format

Step 2: Identify cause of no results

Final Answer:

Quick Check:

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