Hello all,I have another question related to the new statistics abilities when querying features through the REST API in 10.1. It seems that if I use a field to group the resulting statistics values, and if any records in the feature layer or table contain null values in the specified field, I get a valid-looking response, but with an empty 'features' value. When no values are null, here's an example of what the response looks like when I ask for the stats to be grouped by a column named "integer_attribute":{
"displayFieldName": "",
"fieldAliases": {
"integer_attribute": "integer_attribute",
"total": "total"
},
"fields": [
{
"name": "integer_attribute",
"type": "esriFieldTypeOID",
"alias": "integer_attribute"
},
{
"name": "total",
"type": "esriFieldTypeDouble",
"alias": "total"
}
],
"features": [
{
"attributes": {
"integer_attribute": 0,
"total": 8659
}
},
{
"attributes": {
"integer_attribute": 1,
"total": 7639
}
}
]
}
However, if any of the records contain a null value for the "integer_attribute", I get the following response:{
"displayFieldName": "",
"fieldAliases": {
"integer_attribute": "integer_attribute",
"total": "total"
},
"fields": [
{
"name": "integer_attribute",
"type": "esriFieldTypeOID",
"alias": "integer_attribute"
},
{
"name": "total",
"type": "esriFieldTypeDouble",
"alias": "total"
}
],
"features": [
]
}
Is this an outcome I should have expected? I was hoping that the result would look more like the first response, but with a third entry that contains the count of records where the integer_attribute is null. However, if this operation is not allowed when the group-by field contains null values, it would be helpful to get some kind of error that indicates what went wrong.If I add a where clause to the query that excludes null values, I'll get results again...so I can still get results for non-null records as long as I do that. However, it would be helpful if I actually could get the total null values, because no data is also a valid type of information (i.e., it helps to reveal information that is not yet known or incomplete). The only workaround I can think of is to request the total statistics (un-grouped) separately, then get the grouped stats for the non-null records...then I'd have to loop through the results and subtract the totals from the un-grouped total...with the remainder being the number of null results. Can anyone suggest a better approach?