CODEWITHSUNDEEP
amazon-dynamodb
Vallabh Patade
Vallabh Patade

Reputation: 5110

Writing dynamoDB "OR" condition query?

I want to query the dynamodb table with boolean or condition like SQL e.g. Get me all the items where attribute1 = "no" or attribute2="no"

I tried with scanRequest.withScanFilter but all the conditions are performed by doing boolean ANDing. How do I do boolean ORing.?

Upvotes: 24

Views: 33973

Answers (3)

obotezat
obotezat

Reputation: 1135

You can also use brackets in a FilterExpression:

const params = {
  TableName: process.env.PROJECTS_TABLE,
  IndexName: 'teamId-createdAt-index',
  KeyConditionExpression: 'teamId = :teamId',
  ExpressionAttributeValues: {
    ':teamId': verifiedJwt.teamId,
    ':userId': verifiedJwt.userId,
    ':provider': verifiedJwt.provider
  },
  FilterExpression: 'attribute_exists(isNotDeleted) and ((attribute_not_exists(isPrivate)) or (attribute_exists(isPrivate) and userId = :userId and provider = :provider))'
};

Upvotes: 6

Erben Mo
Erben Mo

Reputation: 3614

You can set ConditionalOperator of your ScanRequest to "OR". The default value is "AND"

http://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_Scan.html

ScanRequest scanRequest = new ScanRequest("tableName");
scanRequest.setConditionalOperator(ConditionalOperator.OR);

Map<String, Condition> scanFilter = new HashMap<String, Condition>();
scanFilter.put("attribute1", new Condition().withAttributeValueList(new AttributeValue("no")).withComparisonOperator(ComparisonOperator.EQ));
scanFilter.put("attribute2", new Condition().withAttributeValueList(new AttributeValue("no")).withComparisonOperator(ComparisonOperator.EQ));

scanRequest.setScanFilter(scanFilter);
ScanResult scanResult = dynamo.scan(scanRequest);

for(Map<String, AttributeValue> item : scanResult.getItems()) {
    System.out.println(item);
}

Upvotes: 9

b-s-d
b-s-d

Reputation: 5143

If you happen to know the HashKey value, another option would be to use QUERY and a FilterExpression. Here is an example with the Java SDK:

Table table = dynamoDB.getTable(tableName);

Map<String, Object> expressionAttributeValues = new HashMap<String, Object>();
expressionAttributeValues.put(":x", "no");
expressionAttributeValues.put(":y", "no");

QuerySpec spec = new QuerySpec()
    .withHashKey("HashKeyAttributeName", "HashKeyValueHere")
    .withFilterExpression("attribute1 = :x  or attribute2 = :y")
    .withValueMap(expressionAttributeValues);


ItemCollection<QueryOutcome> items = table.query(spec);

Iterator<Item> iterator = items.iterator();

while (iterator.hasNext()) {
    System.out.println(iterator.next().toJSONPretty());
}

See Specifying Conditions with Condition Expressions for more details.

Upvotes: 5

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