Querying Windows Azure Table Storage with multiple query criteria

Captain John picture Captain John · Jan 16, 2014 · Viewed 23.4k times · Source

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

kwill picture kwill · Jan 16, 2014

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://docs.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);