Querying Windows Azure Table Storage with multiple query criteria

Question

I'm trying to query a table in Windows Azure storage and was initially using the TableQuery.CombineFilters in the TableQuery<RecordEntity>().Where function as follows:

TableQuery.CombineFilters(
    TableQuery.GenerateFilterCondition("PartitionKey",   QueryComparisons.GreaterThanOrEqual, lowDate),
    TableOperators.And,
    TableQuery.GenerateFilterCondition("PartitionKey", QueryComparisons.LessThanOrEqual, lowDate),
    TableQuery.GenerateFilterCondition("PartitionKey", QueryComparisons.Equal, entityId)
));

Unfortunately CombineFilters only allows 2 query criteria max. So I'm currently doing this:

var tableQuery = new TableQuery<RecordRowEntity>()
            .Where(TableQuery.CombineFilters("PartitionKey", string.Format("(PartitionKey ge '{0}') and (PartitionKey le '{1}') and (RowKey eq '{2}')", low, high, entityId));

Is there any other way of doing it. Am conerned that the way I'm doing it at present is vulnerable to changes in the way the Azure Api works.

Answer 1

A combined filter can then be combined with another filter, repeating as many times as necessary. See the example "Sample – Query all entities with a PartitionKey=”SamplePK” and RowKey greater than or equal to “5”" at https://learn.microsoft.com/en-us/archive/blogs/windowsazurestorage/windows-azure-storage-client-library-2-0-tables-deep-dive#querying.

string pkFilter = TableQuery.GenerateFilterCondition("PartitionKey", QueryComparisons.Equal, "samplePK");

string rkLowerFilter = TableQuery.GenerateFilterCondition("RowKey", QueryComparisons.GreaterThanOrEqual, "5");

string rkUpperFilter = TableQuery.GenerateFilterCondition("RowKey", QueryComparisons.LessThan, "10");

// Note CombineFilters has the effect of "([Expression1]) Operator (Expression2]), as such passing in a complex expression will result in a logical grouping.
string combinedRowKeyFilter = TableQuery.CombineFilters(rkLowerFilter, TableOperators.And, rkUpperFilter);

string combinedFilter = TableQuery.CombineFilters(pkFilter, TableOperators.And, combinedRowKeyFilter);

// OR 
string combinedFilter = string.Format("({0}) {1} ({2}) {3} ({4})", pkFilter, TableOperators.And, rkLowerFilter, TableOperators.And, rkUpperFilter);
TableQuery query = new TableQuery().Where(combinedFilter);