在单个oracle sql语句中返回多个值

Question

Below is a query that is in java

SELECT achieve_STATUS_CD
FROM achievemnt
WHERE env_id = '?' AND ROWNUM = 1 
ORDER BY achive_status_dt

which needs to return value 'Y' based from another two tables enrollment, provision with below conditions

1. enrollment.achieve_intent = '2'
2. enrollment.BEGIN_DT >= TO_DATE ( 05/01/2011, 'MM/DD/YYYY') 3.provision.RELEASE_DT <= SYSDATE

for the rest all conditions it should return the values from original query (SELECT achieve_STATUS_CD FROM achievemnt WHERE env_id = '?' AND ROWNUM = 1 ORDER BY achive_status_dt)

achievemnt is child table of enrollment

How can i write this logic ?

I have written the below query but it has env_id at 2 places but we cant change that in our java for now so i need to write in a single query which accepts env_id only at once

WITH TMP
     AS (SELECT 'Y' AS achieve_STATUS_CD, env_id
           FROM enrollment r, provision a
          WHERE     r.prov_id = a.prov_id
                AND r.achieve_intent = '2'
                AND a.BEGIN_DT >=
                       TO_DATE (
                          05/01/2011,
                          'MM/DD/YYYY')
                AND a.RELEASE_DT <= SYSDATE AND R.env_ID = '?')
SELECT NVL (F.achieve_STATUS_CD,TMP.achieve_STATUS_CD)
FROM TMP FULL OUTER JOIN
     (SELECT achieve_STATUS_CD
      FROM achievemnt
      WHERE env_id = '?' AND
            ROWNUM = 1
      ORDER BY achive_status_dt
     ) F
     ON TMP.env_ID = F.env_ID;

Answer 1

Your initial query is highly likely to be incorrect. The rownum = 1 predicate in this query is applied before the ORDER BY so you're asking for an arbitrary row where the env_id is whatever bind value and then sorting the resulting single row. Sorting a single row is obviously pointless.

SELECT achieve_STATUS_CD
  FROM achievemnt
 WHERE env_id = '?' 
   AND ROWNUM = 1 
 ORDER BY achive_status_dt

If you want to sort multiple rows and to pick the row with the first achive_status_dt , you'd want something like

SELECT *
  FROM (SELECT achieve_STATUS_CD
          FROM achievemnt
         WHERE env_id = '?' 
         ORDER BY achive_status_dt) a
 WHERE a.ROWNUM = 1 

If your actual question, though, is that the second query does what you want (which seems unlikely given the issue I just mentioned) but you want to do it with a single bind variable, you can simply add another CTE that selects the bind variable from dual and then reference that CTE wherever you'd like

WITH env
     AS (SELECT '?' env_id from dual)
    ,TMP
     AS (SELECT 'Y' AS achieve_STATUS_CD, env_id
           FROM enrollment r, provision a, env
          WHERE     r.prov_id = a.prov_id
                AND r.achieve_intent = '2'
                AND a.BEGIN_DT >=
                       TO_DATE (
                          05/01/2011,
                          'MM/DD/YYYY')
                AND a.RELEASE_DT <= SYSDATE 
                AND R.env_ID = env.env_ID)
SELECT NVL (F.achieve_STATUS_CD,TMP.achieve_STATUS_CD)
FROM TMP FULL OUTER JOIN
     (SELECT achieve_STATUS_CD
      FROM achievemnt
           join env
             on achievement.env_id = env.env_id
      WHERE ROWNUM = 1
      ORDER BY achive_status_dt
     ) F
     ON TMP.env_ID = F.env_ID;

Answer 2

Supposing that :

1- the question of rownum is correct (i agree with Justin)

2- the achievemnt table is always populated

You can release the condition

AND R.env_ID = '?'

on the TMP subquery. In this case, it should be enough that the query is a LEFT outer join based on env_id.

So the full query should become like this (i don't have an sql console to test it)

WITH TMP
 AS (SELECT 'Y' AS achieve_STATUS_CD, env_id
       FROM enrollment r, provision a
      WHERE     r.prov_id = a.prov_id
            AND r.achieve_intent = '2'
            AND a.BEGIN_DT >=
                   TO_DATE (
                      05/01/2011,
                      'MM/DD/YYYY')
            AND a.RELEASE_DT <= SYSDATE ),
F 
AS (SELECT TMP.achieve_STATUS_CD
  FROM achievemnt
  WHERE env_id = '?' AND
        ROWNUM = 1
  ORDER BY achive_status_dt)
SELECT NVL (TMP.achieve_STATUS_CD, F.achieve_STATUS_CD)
FROM F LEFT OUTER JOIN TMP
 ON  F.env_ID=TMP.env_ID;

Note that i inverted the NVL fields: if TMP.achieve_STATUS_CD is not null, ie if a row exists, that value, which is always Y, should be taken, otherwise the value from achievemnt.

If the assuntion 2 is not true, you can invert the 2 subqueries in the outer join.

If you need the record from achievemnt with the oldest date, F may become something like this

SELECT TMP.achieve_STATUS_CD, achive_status_dt, env_id, min(achive_status_dt)  OVER(partition by end_id) min_date
  FROM achievemnt
  WHERE env_id = '?' AND
        achive_status_dt=min_date

Answer 3

This is how I understand your question (and I may be completely wrong): If at least one enrollment/provision pair that matches your criteria exists for an env_id show 'Y', otherwise show the first achievement status for it.

select 
  case when exists
  (
    select *
    from enrollment e
    join provision p on p.prov_id = e.prov_id
    where e.achieve_intent = '2'
    and p.begin_dt >= date '2011-05-01'
    and p.release_dt <= sysdate 
    and e.env_id = :env_id
  ) then 'Y'
  else
  (
    select max(achieve_status_cd) keep (dense_rank first order by achive_status_dt)
    from achievement
    where env_id = :env_id
  ) as status
from dual;

If you want to have :env_id only once in your query, change it slightly to:

select 
  case when exists
  (
    select ...
    and e.env_id = main.env_id
  ) then 'Y'
  else
  (
    select ...
    where env_id = main.env_id
  ) as status
from (select :env_id as env_id from dual) main;