SQL Query - Report

Question

Hi
I need to generate a report like
SELECT table2.band,
count of visitors for Month till Date,
count of Unique visitors for Month till Date,
count of repeat visitors for Month till Date,
count of visitors for Today,
count of Unique visitors for Today,
count of repeat visitors for Today
FROM table1,
table2
WHERE table1.visitorid=table2.visitorid
group by table2.band
Can you please let me know if this query is possible and if yes then how and what could be the best approach from performance aspect?

Answer 1

Hi Kapil,
Any create table/insert would have been very helpful, especially considering the question you had asked.Since it is a weekend and i had some time i have made up some dummy data.
CREATE TABLE master_table1 (x NUMBER)
ALTER TABLE master_table1 ADD CONSTRAINT pri PRIMARY key(x)
CREATE TABLE child_table2(band VARCHAR2(10),visit_date DATE)
ALTER TABLE child_table2 ADD (visitor_id NUMBER)
INSERT INTO master_table1 VALUES(1);
INSERT INTO master_table1 VALUES(2);
INSERT INTO master_table1 VALUES(3);
INSERT INTO master_table1 VALUES(4);
INSERT INTO master_table1 VALUES(5);
INSERT INTO master_table1 VALUES(6);
INSERT INTO master_table1 VALUES(7);
INSERT INTO child_table2 VALUES ('LA',SYSDATE,1);
INSERT INTO child_table2 VALUES ('LA',SYSDATE-1,1);
INSERT INTO child_table2 VALUES ('LA',SYSDATE-2,1);
INSERT INTO child_table2 VALUES ('LA',SYSDATE-3,1);
INSERT INTO child_table2 VALUES ('LA',SYSDATE-4,1);
INSERT INTO child_table2 VALUES ('LA',SYSDATE,2);
INSERT INTO child_table2 VALUES ('LA',SYSDATE-1,2);
INSERT INTO child_table2 VALUES ('LA',SYSDATE-2,2);
INSERT INTO child_table2 VALUES ('LA',SYSDATE-3,2);
INSERT INTO child_table2 VALUES ('LA',SYSDATE-4,2);
INSERT INTO child_table2 VALUES ('LA',SYSDATE,3);
INSERT INTO child_table2 VALUES ('LA',SYSDATE-1,3);
INSERT INTO child_table2 VALUES ('LA',SYSDATE-2,3);
INSERT INTO child_table2 VALUES ('LA',SYSDATE-3,3);
INSERT INTO child_table2 VALUES ('LA',SYSDATE-4,3);
INSERT INTO child_table2 VALUES ('LA',SYSDATE-40,1);
INSERT INTO child_table2 VALUES ('LA',SYSDATE-41,1);
INSERT INTO child_table2 VALUES ('LA',SYSDATE-42,1);
INSERT INTO child_table2 VALUES ('LA',SYSDATE-43,1);
INSERT INTO child_table2 VALUES ('LA',SYSDATE-44,1);
INSERT INTO child_table2 VALUES ('LA',SYSDATE,4);After studying the data i have provided here is the query you need.
SELECT band, SUM(vmd) visitor_month_todate,
SUM(uvmd) uniq_visitors_mnth_todate,
SUM(vd) visitors_today,
SUM(uvd) uniq_visitors_today,
SUM(visitors_rep_mnth) rep_visitors_mnth,
SUM(Visitors_rep_day) rep_visitors_today
FROM(
SELECT band, vmd,
uvmd,
vd,
uvd,
CASE WHEN rm >1 THEN
1
END Visitors_rep_mnth,
CASE WHEN rd >1 THEN
1
END Visitors_rep_day
FROM(
SELECT x,band,COUNT(vis_mnth_dat) vmd,COUNT(DISTINCT vis_mnth_dat) uvmd,COUNT(vis_today) vd,COUNT(DISTINCT vis_today) uvd,
count(vis_repmnth_dat) rm,COUNT(vis_repday_dat) rd
FROM (
SELECT x,visit_date,band,
CASE WHEN visit_date >= trunc(SYSDATE,'MM') THEN
x
END vis_mnth_dat,
CASE WHEN visit_date >= trunc(SYSDATE,'DD') THEN
x
END vis_today,
CASE WHEN visit_date >= trunc(SYSDATE,'MM') THEN
1
END vis_repmnth_dat,
CASE WHEN visit_date >= trunc(SYSDATE,'DD') THEN
1
END vis_repday_dat
FROM master_table1 table1,child_table2 table2
WHERE table1.x=table2.visitor_id
) GROUP BY x,band)
) GROUP BY band
O/P
BAND                             LA
VISITOR_MONTH_TODATE     18
UNIQ_VISITORS_MNTH_TODATE     4
VISITORS_TODAY     3
UNIQ_VISITORS_TODAY     2
REP_VISITORS_MNTH     3
REP_VISITORS_TODAY     1You will still have to benchmark it using your data.
Your output 'may' vary since you will be inserting data with sysdate.
Of course some assumptions
1) No id's are repeated in master_table1
2) visit_date does not contain time part
3) Whatever applicable ;)
Cheers!!!
Bhushan
Added Assumptions