How do I keep all observations with the first set of values within an ID variable

[johnsonjf]

I (SAS 9.3) have a dataset for a training course where students' block grades are in individual rows. If a student fails a block they are held back until the next class where they reattempt the block and must pass before they can continue in training.

I am wanting to create a "first-attempt only" dataset that contains only their block grades up until their point of failure. Conceptually I want SAS to look at each ID and within ID retain only the rows associated with the student's first training attempt. First training attempt is defined as their performance in the training class they started in (e.g., 202001).

For example, in the dataset below, student 1001 progressed through training in class 202001 until Block_3 where they failed. They then resumed training in class 202002 and finished all five blocks. For student 1001 I want to keep their performance in class 202001 (their first training attempt) and drop all observations of subsequent training classes (202002).

This is an example of my dataset. My goal is, within each ID, keep only the observations associated with the trainees first class. For 1001 that's class 202001, for 1002 that's class 202004, etc.

ID	Class	Training_Block	Grade	Status
1001	202001	Block_1	88	PASS
1001	202001	Block_2	76	PASS
1001	202001	Block_3	68	FAIL
1001	202002	Block_3	71	PASS
1001	202002	Block_4	86	PASS
1001	202002	Block_5	90	PASS
1002	202004	Block_1	50	FAIL
1002	202006	Block_1	73	PASS
1002	202006	Block_2	91	PASS
1002	202006	Block_3	95	PASS
1002	202006	Block_4	71	PASS
1002	202006	Block_5	78	PASS
1003	202003	Block_1	76	PASS
1003	202003	Block_2	89	PASS
1003	202003	Block_3	80	PASS
1003	202003	Block_4	95	PASS
1003	202003	Block_5	97	PASS
1004	202008	Block_1	74	PASS
1004	202008	Block_2	70	PASS
1004	202008	Block_3	60	FAIL
1004	202009	Block_3	82	PASS
1004	202009	Block_4	68	FAIL
1004	202010	Block_4	72	PASS
1004	202010	Block_5	90	PASS

This is what I'm conceptually wanting SAS to do. Keep all observations with first class value within each ID and drop all subsequent class values within each ID:

ID	Class	Training_Block	Grade	Status
1001	202001	Block_1	88	PASS
1001	202001	Block_2	76	PASS
1001	202001	Block_3	68	FAIL
1001	202002	Block_3	71	PASS
1001	202002	Block_4	86	PASS
1001	202002	Block_5	90	PASS
1002	202004	Block_1	50	FAIL
1002	202006	Block_1	73	PASS
1002	202006	Block_2	91	PASS
1002	202006	Block_3	95	PASS
1002	202006	Block_4	71	PASS
1002	202006	Block_5	78	PASS
1003	202003	Block_1	76	PASS
1003	202003	Block_2	89	PASS
1003	202003	Block_3	80	PASS
1003	202003	Block_4	95	PASS
1003	202003	Block_5	97	PASS
1004	202008	Block_1	74	PASS
1004	202008	Block_2	70	PASS
1004	202008	Block_3	60	FAIL
1004	202009	Block_3	82	PASS
1004	202009	Block_4	68	FAIL
1004	202010	Block_4	72	PASS
1004	202010	Block_5	90	PASS

This is my desired output:

ID	Class	Training_Block	Grade	Status
1001	202001	Block_1	88	PASS
1001	202001	Block_2	76	PASS
1001	202001	Block_3	68	FAIL
1002	202004	Block_1	50	FAIL
1003	202003	Block_1	76	PASS
1003	202003	Block_2	89	PASS
1003	202003	Block_3	80	PASS
1003	202003	Block_4	95	PASS
1003	202003	Block_5	97	PASS
1004	202008	Block_1	74	PASS
1004	202008	Block_2	70	PASS
1004	202008	Block_3	60	FAIL

I feel like I've done this before and it involved do loops and first.dot and last.dot processing, but for the life of me I can't figure out how to do it this time.

Thanks in advance for help!

[Shmuel]

Try next code:

data want;
 set have;
    by id ;
         retain flag;
        if first.id then flag=0;
        if status = 'FAIL' then flag=1;
        if not flag=1;
run;