Query last data of different documents in Azure Cosmos db (SQL)

问题

Sample data :

{age: 20, ts: '00:00'},
{age: 20, ts: '00:01'},
{age: 30, ts: '00:00'},
{age: 30, ts: '00:01'},
{age: 40, ts: '00:00'},
{age: 40, ts: '00:01'},
{age: 40, ts: '00:02'}

Expected output:

[{age: 20, ts: '00:01'},
{age: 30, ts: '00:01'},
{age: 40, ts: '00:02'}]

Tried

SELECT * FROM c where c.age in (20, 30, 40) order by c.ts desc

But the result selected all data.

回答1:

Please try something like the following:

SELECT max(c.ts) as ts, c.age FROM c where c.age in (20, 30, 40) 
Group By c.age

This gives the following output:

[
    {
        "ts": "00:02",
        "age": 40
    },
    {
        "ts": "00:01",
        "age": 30
    },
    {
        "ts": "00:01",
        "age": 20
    }
]

来源：https://stackoverflow.com/questions/62527835/query-last-data-of-different-documents-in-azure-cosmos-db-sql