Query comparison

Question

Hello ,
I would really apreciate if some one can help me with there
expert opinion.
Mentioned below is a query
SELECT
S.ACCT_EVENT_TYPE_CD
,S.CUST_ACCT_EVENT_ID
,S.EVENT_USED_BY_CD
,S.EVENT_SEQUENCE_CD
,S.DW_AS_OF_DT
,S.CUST_ACCT_EVENT_CD
,S.EXT_EVENT_REF_CD
,S.EVENT_START_DT
,S.EVENT_END_DT
,S.AUDIT_USER_ID
,S.AUDIT_UPDT_TS
,S.DW_ACTN_IN
,S.DW_DATA_CHG_TS
,S.DW_LOAD_TS
FROM
IDW_STAGE.CUST_ACCT_EVENT_S S
LEFT OUTER JOIN
(SELECT ACCT_ID,
CUST_ID,
EVNT_USE_BY_CD,
EVNT_SEQ_CD,
MAX(DW_EFF_DT) DW_EFF_DT
FROM IDW_DATA.CUST_ACCT_EVENT_T
GROUP BY 1,2,3,4) T
ON
( T.ACCT_ID=0
AND T.CUST_ID=S.CUST_ACCT_EVENT_ID
AND S.ACCT_EVENT_TYPE_CD='C'
OR
( T.CUST_ID=0
AND T.ACCT_ID=S.CUST_ACCT_EVENT_ID
AND S.ACCT_EVENT_TYPE_CD='A'
AND T.EVNT_USE_BY_CD = S.EVENT_USED_BY_CD
AND T.EVNT_SEQ_CD = S.EVENT_SEQUENCE_CD
WHERE
S.DW_AS_OF_DT > T.DW_EFF_DT
AND
S.DW_ACTN_IN in ('I','U');
Will there be a difference in output in terms of data(not performance) if we modify the above mentioned query as
SELECT
S.ACCT_EVENT_TYPE_CD
,S.CUST_ACCT_EVENT_ID
,S.EVENT_USED_BY_CD
,S.EVENT_SEQUENCE_CD
,S.DW_AS_OF_DT
,S.CUST_ACCT_EVENT_CD
,S.EXT_EVENT_REF_CD
,S.EVENT_START_DT
,S.EVENT_END_DT
,S.AUDIT_USER_ID
,S.AUDIT_UPDT_TS
,S.DW_ACTN_IN
,S.DW_DATA_CHG_TS
,S.DW_LOAD_TS
FROM
idw_stage.CUST_ACCT_EVENT_S S
LEFT OUTER JOIN
(SELECT ACCT_ID,
CUST_ID,
EVNT_USE_BY_CD,
EVNT_SEQ_CD,
MAX(DW_EFF_DT) DW_EFF_DT
FROM idw_data.CUST_ACCT_EVENT_T
GROUP BY 1,2,3,4) T
ON T.ACCT_ID=0
AND T.CUST_ID=S.CUST_ACCT_EVENT_ID
AND S.ACCT_EVENT_TYPE_CD='C'
AND T.EVNT_USE_BY_CD = S.EVENT_USED_BY_CD
AND T.EVNT_SEQ_CD = S.EVENT_SEQUENCE_CD
WHERE
S.DW_AS_OF_DT > COALESCE(T.DW_EFF_DT,date '0001-01-01')
AND
S.DW_ACTN_IN in ('I','U')
UNION
SELECT
S.ACCT_EVENT_TYPE_CD
,S.CUST_ACCT_EVENT_ID
,S.EVENT_USED_BY_CD
,S.EVENT_SEQUENCE_CD
,S.DW_AS_OF_DT
,S.CUST_ACCT_EVENT_CD
,S.EXT_EVENT_REF_CD
,S.EVENT_START_DT
,S.EVENT_END_DT
,S.AUDIT_USER_ID
,S.AUDIT_UPDT_TS
,S.DW_ACTN_IN
,S.DW_DATA_CHG_TS
,S.DW_LOAD_TS
FROM
idw_stage.CUST_ACCT_EVENT_S S
LEFT OUTER JOIN
(SELECT ACCT_ID,
CUST_ID,
EVNT_USE_BY_CD,
EVNT_SEQ_CD,
MAX(DW_EFF_DT) DW_EFF_DT
FROM idw_data.CUST_ACCT_EVENT_T
GROUP BY 1,2,3,4) T
ON T.CUST_ID=0
AND T.ACCT_ID=S.CUST_ACCT_EVENT_ID
AND S.ACCT_EVENT_TYPE_CD='A'
AND T.EVNT_USE_BY_CD = S.EVENT_USED_BY_CD
AND T.EVNT_SEQ_CD = S.EVENT_SEQUENCE_CD
WHERE
S.DW_AS_OF_DT > COALESCE(T.DW_EFF_DT,date '0001-01-01')
AND
S.DW_ACTN_IN in ('I','U')
Thanxs

Answer 1

I think the number oof records will be same.
But would this be sufficient?
SELECT S.ACCT_EVENT_TYPE_CD
      ,S.CUST_ACCT_EVENT_ID
      ,S.EVENT_USED_BY_CD
      ,S.EVENT_SEQUENCE_CD
      ,S.DW_AS_OF_DT
      ,S.CUST_ACCT_EVENT_CD
      ,S.EXT_EVENT_REF_CD
      ,S.EVENT_START_DT
      ,S.EVENT_END_DT
      ,S.AUDIT_USER_ID
      ,S.AUDIT_UPDT_TS
      ,S.DW_ACTN_IN
      ,S.DW_DATA_CHG_TS
      ,S.DW_LOAD_TS
FROM IDW_STAGE.CUST_ACCT_EVENT_S S
LEFT OUTER JOIN
(SELECT ACCT_ID,
        CUST_ID,
        EVNT_USE_BY_CD,
        EVNT_SEQ_CD,
        MAX(DW_EFF_DT) DW_EFF_DT
FROM IDW_DATA.CUST_ACCT_EVENT_T
GROUP BY 1,2,3,4) T
ON
( T.ACCT_ID=0
AND T.CUST_ID=S.CUST_ACCT_EVENT_ID
AND S.ACCT_EVENT_TYPE_CD in ('C', 'A')
AND T.EVNT_USE_BY_CD = S.EVENT_USED_BY_CD
AND T.EVNT_SEQ_CD = S.EVENT_SEQUENCE_CD
WHERE
S.DW_AS_OF_DT > T.DW_EFF_DT
AND
S.DW_ACTN_IN in ('I','U');Illustration on number of records.
SQL> with t as (select '1' a from dual
  2             union
  3             select '2' a from dual
  4             union
  5             select '3' a from dual
  6             union
  7             select '4' a from dual
  8             union
  9             select '5' a from dual
10             union
11             select '6' a from dual
12             union
13             select '4' a from dual)
14  select a from t
15  where t.a = '1'
16  or t.a = '4';
A
1
4
2 rows selected.
SQL> with t as (select '1' a from dual
  2             union
  3             select '2' a from dual
  4             union
  5             select '3' a from dual
  6             union
  7             select '4' a from dual
  8             union
  9             select '5' a from dual
10             union
11             select '6' a from dual
12             union
13             select '4' a from dual)
14  select a from t
15  where t.a = '1'
16  union
17  select a from t
18  where t.a = '4';
A
1
4
2 rows selected.
SQL>Cheers
Sarma.