Crystal Reports案例陈述

Question

I have two tables, [TASKS] and [EVENTS] . [EVENTS] is linked to [TASKS] by the key [EVENTS.TASKID] = [TASKS.TASKID] with a one-to-many relationship (ie each task can have multiple events).

I am trying to write a Crystal Report that will return the number of tasks that do, and the number of tasks that do not have a specific event type.

In SQL I'd use a Case statement, but can't see how to achieve this in Crystal. The output I'm after is something along the lines of:

                | # |
----------------+---+
Has event       | 5 |
----------------+---+
No event        | 9 |
----------------+---+
Total           | 14|
----------------+---+

Answer 1

Group on Task

Create a formula that Returns 1 if the event type matches and zero otherwise.

Place a formula in the Task Group Footer that adds 1 to a global variable if the MAX of that formula by Task group is 1. Use a Report Formula to display the final value of that global variable.

Same logic for MAX = 0 applies to the question of how many Tasks don't have a matching events.