Seeking hints to simplify complex query - oracle

Question

Building a web page to show summary data and a chart. The query to obtain my summary data appears to be overly complex and there must be a simpler way to accomplish. I'm mainly experienced with SQL Server, and under SQL Server, getting row and column level totals is done within the main query. No unions or sub queries required, unless you are doing some more complex things.
However, under Oracle 10g, this appears to be the way to accomplish the same thing.
The resulting data is put into a JSON array and populates a v1.10 DataTable.
The source data has a row containing the date, item and a count of items.
The ending table uses a pivot, becoming 8 columns, 6 for the items, a date and row-level total. I trimmed 2 columns to simplify reduce the clutter in the question. The final row has column-level totals and the final grand total. Any suggestions welcome.
The query is here
SELECT *
FROM (
SELECT TO_CHAR("DATE", 'MM/DD/YYYY') AS "DATE"
, ITEM_NAME
, SUM(ITEM_COUNT) AS TOTAL
FROM MY_VIEW
WHERE 1=1
AND "DATE" > ADD_MONTHS(TO_DATE(SYSDATE, 'DD-MM-RR'), -1)
AND ITEM_NAME IN ('ITEM-01','ITEM-02','ITEM-03','ITEM-04')
GROUP BY "DATE", ITEM_NAME
UNION ALL
SELECT TO_CHAR("DATE", 'MM/DD/YYYY') AS "DATE"
, 'ROW_TOTAL' AS ITEM_NAME
, SUM(ITEM_COUNT) AS TOTAL
FROM MY_VIEW
WHERE 1=1
AND "DATE" > ADD_MONTHS(TO_DATE(SYSDATE, 'DD-MM-RR'), -1)
AND ITEM_NAME IN ('ITEM-01','ITEM-02','ITEM-03','ITEM-04')
GROUP BY "DATE"
)
PIVOT
(
MAX(TOTAL) FOR ITEM_NAME IN ('ITEM-01','ITEM-02','ITEM-03','ITEM-04','ROW_TOTAL')
)
UNION ALL
SELECT *
FROM (
SELECT 'GRAND TOTAL' AS "DATE"
, ITEM_NAME
, SUM(ITEM_COUNT) AS TOTAL
FROM MY_VIEW
WHERE 1=1
AND "DATE" > ADD_MONTHS(TO_DATE(SYSDATE, 'DD-MM-RR'), -1)
AND ITEM_NAME IN ('ITEM-01','ITEM-02','ITEM-03','ITEM-04')
GROUP BY ITEM_NAME
UNION ALL
SELECT 'GRAND TOTAL' AS "DATE"
, 'ROW_TOTAL' AS ITEM_NAME
, SUM(ITEM_COUNT) AS TOTAL
FROM MY_VIEW
WHERE 1=1
AND "DATE" > ADD_MONTHS(TO_DATE(SYSDATE, 'DD-MM-RR'), -1)
AND ITEM_NAME IN ('ITEM-01','ITEM-02','ITEM-03','ITEM-04')
)
PIVOT
(
MAX(TOTAL) FOR ITEM_NAME IN ('ITEM-01','ITEM-02','ITEM-03','ITEM-04', 'ROW_TOTAL')
)
ORDER BY 1
And the end results should look like this:
DATE ITEM-01 ITEM-02 ITEM-03 ITEM-04 ROW_TOTAL
======================================================
4/18/17 1,063,008 460,436 106,715 97,532 1,829,364
4/19/17 1,061,819 479,338 103,946 108,179 1,859,825
4/20/17 1,095,853 536,835 107,437 101,949 1,944,677
4/21/17 1,153,345 642,364 108,940 106,988 2,121,068
4/22/17 1,075,849 633,873 102,459 99,999 2,012,710
4/23/17 913,952 591,783 95,291 100,144 1,794,358
4/24/17 1,036,377 626,043 115,105 98,339 1,977,043
4/25/17 1,079,163 602,237 118,189 100,478 2,001,529
4/26/17 1,110,499 639,640 109,793 103,360 2,069,311
4/27/17 1,119,696 620,081 105,781 108,276 2,061,452
4/28/17 1,125,676 618,763 113,234 96,326 2,057,169
4/29/17 1,026,974 620,059 102,856 96,150 1,940,394
4/30/17 903,913 539,694 83,531 97,073 1,716,114
5/1/17 1,043,598 590,027 100,272 96,519 1,932,843
5/2/17 1,074,912 623,392 101,793 97,724 2,000,981
5/3/17 1,078,865 620,662 101,699 102,900 2,010,014
5/4/17 1,090,501 628,785 110,248 103,593 2,040,658
5/5/17 1,125,984 686,945 128,657 105,356 2,150,037
5/6/17 1,031,267 625,189 117,290 99,358 1,967,819
5/7/17 921,467 551,497 97,482 93,520 1,752,940
5/8/17 1,064,291 624,366 93,463 98,860 1,979,863
5/9/17 1,085,062 661,509 97,791 98,083 2,039,114
5/10/17 1,103,794 634,868 94,364 102,345 2,033,911
5/11/17 1,107,449 617,931 94,420 103,717 2,024,126
5/12/17 1,130,463 647,744 97,616 102,684 2,079,009
5/13/17 1,056,653 621,182 96,743 99,801 1,974,710
5/14/17 970,969 583,865 87,953 97,682 1,831,516
5/15/17 1,075,979 633,102 95,356 101,336 2,003,830
5/16/17 1,094,805 634,421 96,802 99,533 2,026,891
GRAND TOTAL 30,822,183 17,596,631 2,985,226 2,917,804 57,233,276

Answer 1

It might go faster if you use 'analytical queries' to perform totalling without needing to run separate grouping queries. An example analytic expression might be:
Select
Sum(item_count) over(partition by date) --btw "date" is a poor name choice for a column
From
Table
Where
Item_name in ...
Or alternatively, use 'grouping sets', 'cube' or 'rollup'
The difference? Analytics establish grouping characteristics that add an extra column to a report with aggregation of the row. Grouping sets, cubes and roll ups add extra rows to a report with aggregations of a column
Apologies for not giving an example of this; they're quite an extensive topic requiring in depth discussion so it's partly beyond the scope of my answer, and partly that I'm writing this on an iPad with no recent use of them to call on from memory (the topic is that vast) and no way to test or run one, so I'll leave it as a pointer for you to do further background research. Essentially a grouping set is an instruction akin to "here's a single data set, iterate it once and perform these N number of different group by aggregates as you go.." essentially one group would be by date and name (so single lines are output) and the other group by is probably by name (so totals for each name are output)..
then do your pivot. For more info, the 'phrases in quotes' are what you'd look up in the manual/web
All this is a little bit dirty, by the way.. your reporting tool from end should really be building this summary, rather than oracle, though doing grouping (but not pivoting) in the DB helpfully reduces network traffic