Oracle按日期和数字查询条形图

Question

I have this table which I use to store 4 types of messages: info, warn, alarm and error.

CREATE TABLE EVENTS(
  EVENTID INTEGER NOT NULL,
  SOURCE VARCHAR2(50 ),
  TYPE VARCHAR2(50 ),
  EVENT_DATE DATE,
  DESCRIPTION VARCHAR2(100 )
)
/

I need to display the events by type and day in a bar chart 15 days into the past for example:

Can you help me for this Oracle query?

Example output from query:

|11-12-2015 | 12 | 22 | 11 |
|12-12-2015 | 32 | 12 | 14 |
|13-12-2015 | 12 | 22 | 11 |
|14-12-2015 | 12 | 22 | 11 |

Answer 1

You can just use conditional aggregation:

select event_date,
       sum(case when type = 'Error' then 1 else 0 end) as Error,
       sum(case when type = 'Warn' then 1 else 0 end) as Warn,
       sum(case when type = 'Info' then 1 else 0 end) as Info
from events e
where event_date >= trunc(sysdate) - 15
group by event_date
order by event_date;

Caveat: if the field called event_date actually has a time component, then you should use trunc(event_date) in the select and group by .

Answer 2

Variant A: line by line You want the number (=COUNT(*)) of eg error (=TYPE) events of a specific source at a specific event_date. So the triple ( source, type, event_date) build a group and you want to know, how many events are in this group.

Select source, type, event_date, count(*) 
from events 
group by source, type, event_date;

With this the results would be

event_date  source  type   count
11-12-2015  server  error  12
11-12-2015  server  info   22
11-12-2015  server  warn   11
12-12-2015  server  error  32
12-12-2015  server  info   12
12-12-2015  server  warn   14

Variant B: side by side

Select event_date, source, sum(error), sum(info), sum(warn)
From (select event_date, source, 
decode(Type, 'error', 1, 0) as error,
decode(Type, 'info', 1, 0) as info,
decode(Type, 'warn', 1, 0) as warn
From events)
Group by event_date, source;

You should get:

event_date  source  error  warn  info
11-12-2015  server   12    22    11
12-12-2015  server   32    12    14

decode is some kind of if-then-else.

Optional: only 15 days back As you asked.

Simple add where clause to the (inner) select, like where event_date >= sysdate - 15

Select source, type, event_date, count(*) 
from events 
where event_date >= sysdate - 15
group by source, type, event_date;

or for b)

Select event_date, source, sum(error), sum(info), sum(warn)
From (select event_date, source, 
decode(Type, 'error', 1, 0) as error,
decode(Type, 'info', 1, 0) as info,
decode(Type, 'warn', 1, 0) as warn
From events
where event_date >= sysdate - 15)
Group by event_date, source;