“ SELECT DISTINCT”查询带回太多唯一行

Question

I'm working on a relatively simple query at this stage and I'm wondering how I can derive a single row of data when there is a change in column data (status). I know this sounds like jumble, I'm just not sure how to put it in correct terms so, I'm just going to show you!

I'm trying to extract the highest datestamp in column (whse_load_ts) where column (whse_ac) does not have a value of Y. I want this to return one row.

C_CLM   C_STA_CLM   WHSE_ACTN_CD    WHSE_CURR_ROW_IND   WHSE_LOAD_TS
12056733           AC                  U                     2012-05-30 03:18:12

Currently it is returning two rows because of the change in status c_sta_clm.

C_CLM     C_STA_CLM  WHSE_ACTN_CD   WHSE_CURR_ROW_IND         WHSE_LOAD_TS
12056733         AC             U                      2012-05-30 03:18:12
12056733         PC             U                      2012-04-28 03:19:38

All of the data for this specific claim looks like this:

 12056733   PC  I       2012-02-04 03:20:25.150
 12056733   PC  U       2012-02-07 03:19:43.230
 12056733   PC  U       2012-02-11 03:21:31.440
 12056733   PC  U       2012-04-28 03:19:38.380
 12056733   AC  U       2012-05-17 03:18:25.920
 12056733   AC  U       2012-05-19 03:20:33.200
 12056733   AC  U       2012-05-30 03:18:12.370
 12056733   TE  U   Y   2012-06-06 03:20:07.520

Query is as follows

SELECT 
    c_clm,
    c_sta_clm,
    whse_curr_row_ind,
    max(whse_load_ts) as "Loaded"
FROM 
    pearl_p.TLTC900_CLM_PRSST
WHERE 
    whse_curr_row_ind not in('y')
AND c_clm = '12056733'
group by 1,2,3

Basically it's pulling the max date for each status AC/PC when i just want the max date for anything without a Y in the whse_curr_row_ind column

Answer 1

You can do this with a sub-query:

SELECT 
    p1.c_clm,
    p1.c_sta_clm,
    p1.whse_curr_row_ind,
    p2.Loaded
FROM pearl_p.TLTC900_CLM_PRSST p1
INNER JOIN
(
    select max(whse_load_ts) as Loaded, C_CLM
    from  pearl_p.TLTC900_CLM_PRSST
    where whse_curr_row_ind not in('y')
    group by C_CLM
) p2
    on p1.whse_load_ts = p2.Loaded
    and p1.C_CLM = p2.C_CLM
WHERE p1.whse_curr_row_ind not in('y')