Count
If you want to count the number of items in a result set instead of returning the
items, use count(*). Instead of returning a list of items, Amazon SimpleDB returns
a single item called Domain with a Count attribute.
Note
If the count request takes more than five seconds, Amazon SimpleDB returns the number of items that it could count and a next token to return additional results. The client is responsible for accumulating the partial counts.
If Amazon SimpleDB returns a 408 Request Timeout, please resubmit the request.
The default result limit of 100 and maximum result limit of 2500 do not apply to count(*). However, you can restrict the maximum number of counted results using the limit clause.
The next token returned by count(*) and select are interchangeable
as long as the where and order by clauses match. For example, if you want to return
the 200 items after the first 10,000 (similar to an offset), you can perform a count with a limit clause of 10,000
and use the next token to return the next 200 items with select.
The following table shows count(*) queries and the results they
return from the sample dataset.
Note
To view the source data for the queries, see Sample Query Data Set.
| Select Expression | Description | Result |
|---|---|---|
select count(*) from mydomain where Title = 'The Right Stuff' |
Counts all items where the attribute "Title" equals "The Right Stuff." | 1 |
select count(*) from mydomain where Year > '1985' |
Counts all items where "Year" is greater than "1985." |
3 |
select count(*) from mydomain limit 500 |
Counts all items in the domain, with a limit of 500. | 6 |
select count(*) from mydomain limit 4 |
Counts all items in the domain, with a limit of 4. | 4 |
