“Simple” SQL Query

Question

Each of my clients can have many todo items and every todo item has a due date.

What would be the query for discovering the next undone todo item by due date for eac

Answer 1

The following should get you close, first get the min time for each client, then lookup the client/todo information

SELECT
    C.Id,
    C.Name,
    T.Id
    T.Description,
    T.timestamp_due
FROM
{
    SELECT
        client_id,
        MIN(timestamp_due) AS "DueDate"
    FROM todos
    WHERE timestamp_completed IS NULL
    GROUP BY ClientId
} AS MinValues
    INNER JOIN Clients C
    ON (MinValues.client_id = C.Id)
    INNER JOIN todos T
    ON (MinValues.client_id = T.client_id
        AND MinValues.DueDate = T.timestamp_due)
ORDER BY C.Name

NOTE: Written assuming SQL Server