Oracle SQL按字符串聚合字段分组

Question

I'm having a problem grouping a field in my query. Here is an example of what I'm talking about:

Example:

AIR_DT             DOL_GAP_TIME         MATL_SIZE                     
15-JAN-15          8:00 AM              30
15-JAN-15          8:00 AM              25
15-JAN-15          9:00 AM              5
15-JAN-15          9:00 AM              10
15-JAN-15          9:00 AM              5
15-JAN-15          9:00 AM              20

Those with same time should be grouped as one, summing up their matl_size

Expected output:

AIR_DT             DOL_GAP_TIME         MATL_SIZE                     
15-JAN-15          8:00 AM              55
15-JAN-15          9:00 AM              40

Here is my SQL:

SELECT 
      a.air_dt, 
      TRIM(SUBSTR(TO_CHAR (a.dol_pref_start_time, 'mm/dd/yyyy hh:mi:ss AM'),12,2))
      || ':00 '
      || TRIM(SUBSTR (TO_CHAR (a.dol_pref_start_time, 'mm/dd/yyyy hh:mi:ss    AM'),
21, 2)) dol_gap_time, e.matl_size
FROM order_implem_dtl_broadcast a, matl_mstr b, matl_size_mstr e 
WHERE a.matl_id = b.matl_id 
AND b.matl_size_id = e.matl_size_id  
AND a.air_dt LIKE '%15-JAN-15%'
GROUP BY a.air_dt, a.dol_pref_start_time, e.matl_size
ORDER BY a.air_dt, a.dol_pref_start_time;

Thank you for helping in advance!

Answer 1

Based on your sample data, this should do what you want:

select AIR_DT, DOL_GAP_TIME, sum(MATL_SIZE)
from table t
group by AIR_DT, DOL_GAP_TIME;

However, I have no idea what this has to do with the query in the question.

Answer 2

OK let's start with your initial query:

SELECT 
  a.air_dt, 
  TRIM(SUBSTR(TO_CHAR (a.dol_pref_start_time, 'mm/dd/yyyy hh:mi:ss AM'),12,2))
  || ':00 '
  || TRIM(SUBSTR (TO_CHAR (a.dol_pref_start_time, 'mm/dd/yyyy hh:mi:ss    AM'), 21, 2)) dol_gap_time, e.matl_size
  FROM order_implem_dtl_broadcast a, matl_mstr b, matl_size_mstr e 
 WHERE a.matl_id = b.matl_id 
   AND b.matl_size_id = e.matl_size_id  
   AND a.air_dt LIKE '%15-JAN-15%'
 GROUP BY a.air_dt, a.dol_pref_start_time, e.matl_size
 ORDER BY a.air_dt, a.dol_pref_start_time;

I see a couple of problems. One, you're grouping by e.matl_size even though that is the column you want to SUM() . You don't want it in the GROUP BY . Second, your manner of getting the time from dol_pref_start_time is really odd. It looks like you want to round down to the hour, then just get the hour plus whether it is AM or PM. So this:

TRIM(SUBSTR(TO_CHAR (a.dol_pref_start_time, 'mm/dd/yyyy hh:mi:ss AM'),12,2))
  || ':00 '
  || TRIM(SUBSTR (TO_CHAR (a.dol_pref_start_time, 'mm/dd/yyyy hh:mi:ss    AM'), 21, 2)) dol_gap_time

can simply be this:

TO_CHAR(TRUNC(a.dol_pref_start_time, 'HH'), 'HH:MI AM') AS dol_gap_time

Third, are your dates stored as dates ? If so, why are you doing this?

AND a.air_dt LIKE '%15-JAN-15%'

It would be far better to do this:

AND TRUNC(a.air_dt) = date'2015-01-15'

or, if you have an index on a.air_dt , this:

AND a.air_dt >= date'2015-01-15'
AND a.air_dt < date'2015-01-16'

Putting this all together, we get something like this (note that I've also converted your joins to ANSI SQL joins):

SELECT TRUNC(a.air_dt) AS air_dt
     , TO_CHAR(TRUNC(a.dol_pref_start_time, 'HH'), 'HH:MI AM') AS dol_gap_time
     , SUM(e.matl_size) AS matl_size
  FROM order_implem_dtl_broadcast a INNER JOIN matl_mstr b
    ON a.matl_id = b.matl_id
 INNER JOIN matl_size_mstr e 
    ON b.matl_size_id = e.matl_size_id
 WHERE a.air_dt >= date'2015-01-15'
   AND a.air_dt < date'2015-01-16'
 GROUP BY TRUNC(a.air_dt), TO_CHAR(TRUNC(a.dol_pref_start_time, 'HH'), 'HH:MI AM')
 ORDER BY air_dt, TO_DATE(dol_gap_time, 'HH:MI AM'); -- using aliases in the ORDER BY, converting dol_gap_time to DATE for sorting