How to loop a single output from a query - sql

Assuming the query below returns a single value:
SELECT date FROM dual WHERE name = 'max'
21-05-2011
How it can loop the previous single value result to return:
21-05-2011
21-06-2011
21-07-2011
21-08-2011


Expanding on comments, you can use the same mechanism shown in your previous question, just replacing the fixed date value with the column name and dual with your real table.
With your pseudocode:
select add_months(date, level-1)
from dual
where name = 'max'
connect by level <= 4
... but as dual is a real table that doesn't have those columns and date is a reserved word, it would be more like:
select add_months(your_date_column, level-1)
from your_table
where name = 'max'
connect by level <= 4
As a demo, I'll create a table with a single row that matches your filter and has your date:
create table your_table (name varchar2(10), your_date_column date);
insert into your_table (name, your_date_column)
values ('max', date '2011-05-21');
select add_months(your_date_column, level-1)
from your_table
where name = 'max'
connect by level <= 4;
ADD_MONTHS(YOUR_DATE_COLUMN,LEVEL-1)
------------------------------------
2011-05-21
2011-06-21
2011-07-21
2011-08-21
You just need to substitute your actual table and column names.

Related

SQL Query to select a specific part of the values in a column

I have a table in a database and one of the columns of the table is of the format AAA-BBBBBBB-CCCCCCC(in the table below column Id) where A, B and C are all numbers (0-9). I want to write a SELECT query such that for this column I only want the values in the format BBBBBBB-CCCCCCC. I am new to SQL so not sure how to do this. I tried using SPLIT_PART on - but not sure how to join the second and third parts.
Table -
Id
Name
Age
123-4567890-1234567
First Name
199
456-7890123-4567890
Hulkamania
200
So when the query is written the output should be like
Output
4567890-1234567
7890123-4567890

As mentioned in the request comments, you should not store a combined number, when you are interested in its parts. Store the parts in separate columns instead.
However, as the format is fixed 'AAA-BBBBBBB-CCCCCCC', it is very easy to get the substring you are interested in. Just take the string from the fifth position on:
select substr(col, 5) from mytable;

You can select the right part of a column starting at the 4th character
SELECT RIGHT(Id, LEN(Id)-4) AS TrimmedId;

Another option using regexp_substr
with x ( c1,c2,c3 ) as
(
select '123-4567890-1234567', 'First Name' , 199 from dual union all
select '456-7890123-4567890', 'Hulkamania' , 200 from dual
)
select regexp_substr(c1,'[^-]+',1,2)||'-'||regexp_substr(c1,'[^-]+',1,3) as result from x ;
Demo
SQL> with x ( c1,c2,c3 ) as
(
select '123-4567890-1234567', 'First Name' , 199 from dual union all
select '456-7890123-4567890', 'Hulkamania' , 200 from dual
)
select regexp_substr(c1,'[^-]+',1,2)||'-'||regexp_substr(c1,'[^-]+',1,3) as result from x ; 2 3 4 5 6
RESULT
--------------------------------------------------------------------------------
4567890-1234567
7890123-4567890
SQL>

Extracting most recent date from VARCHAR2

Data:
USER_ID VIOLATION_DATES
--------------------------------
1 18-Jul-21 > 24-Jul-21
2 05-Aug-21
3 09-Jun-21
1 18-Jul-21
I have a table that has columns for Users and their dates of violations. I want to extract the most recent violation for each user.
This is the query I've written:
select
USR_ID,
max(to_date(VIOLATION_DATES, 'DD-MON-YY')) as Most_Recent_VIOLATIONS
from
table
group by
USR_ID
However I get this error:
ORA-01830: date format picture ends before converting entire input string
I believe it has something to do with the way the most recent violation is appended (18-Jul-21 > 24-Jul-21 ). Can anyone provide any clarity on how I can extract the most recent date for each user? for example:
USER_ID VIOLATION_DATES
--------------------------
1 24-Jul-21
2 05-Aug-21
3 09-Jun-21
I understand that this storage method isn't ideal but this is out of my control.

You can split the multi-value string into separate rows, then "group by" as normal (the with clause is just to provide test data - substitute your actual table):
with demo (user_id, violation_dates) as
( select 1, '18-Jul-21 > 24-Jul-21' from dual union all
select 2, '05-Aug-21' from dual union all
select 3, '09-Jun-21' from dual union all
select 1, '18-Jul-21' from dual )
select user_id
, max(to_date(regexp_substr(d.violation_dates, '[^> ]+', 1, r.rn) default null on conversion error,'DD-MON-YY')) as violation_date
from demo d
cross apply
( select rownum as rn
from dual connect by rownum <= regexp_count(d.violation_dates,'>') +1 ) r
group by user_id
order by 1;
"default null on conversion error" requires Oracle 12.2.

Make in (SQL) dynamic for incoming values

Is it possible for in statement to be dynamic? like dynamic comma separation
for example:
DATA=1
select * from dual
where
account_id in (*DATA);
DATA=2
select * from dual
where
account_id in (*DATA1,*DATA2);
FOR DATA=n
how will i make the in statement dynamic/flexible (comma) for unknown quantity.
select * from dual
where
account_id in (*DATAn,*DATAn+1,etc);

A hierarchical query might help.
acc CTE represents sample data
lines #9 - 11 are what you might be looking for; data is concatenated with level pseudocolumn's value returned by a hierarchical query
Here you go:
SQL> with acc (account_id) as
2 (select 'data1' from dual union all
3 select 'data2' from dual union all
4 select 'data3' from dual union all
5 select 'data4' from dual
6 )
7 select *
8 from acc
9 where account_id in (select 'data' || level
10 from dual
11 connect by level <= &n
12 );
Enter value for n: 1
ACCOU
-----
data1
SQL> /
Enter value for n: 3
ACCOU
-----
data1
data2
data3
SQL>

As I can see, You are using the number in Where clause, Substitution will be enough to solve your problem.
See the example below:
CREATE table t(col1 number);
insert into t values(1);
insert into t values(2);
insert into t values(3);
-- Substitution variable initialization
define data1=1;
define data2='1,2';
--
-- With data1
select * from t where col1 in (&data1);
Output:
-- With data2
select * from t where col1 in (&data2);
Output:
Hope, This will be helpful to you.
Cheers!!

The basic problem is not the listagg function but a major misconception that just because elements in a string list are comma separated that a string with commas in it is a list. Not So. Consider a table with the following rows.
Key
- Data1
- Data2
- Data1,Data2
And the query: Select * from table_name where key = 'wanted_key'; Now if all commas separate independent elements then what value in for "wanted_Key" is needed to return only the 3rd row above? Even with the IN predicate 'Data1,Data2' is still just 1 value, not 2. For 2 values it would have to be ('Data1','Data2').
The problem you're having with Listagg is not because of the comma but because it's not the appropriate function. Listagg takes values from multiple rows and combines then into a single comma separated string but not comma separated list. Example:
with elements as
( select 'A' code, 'Data1' item from dual union all
select 'A', 'Data2' from dual union all
select 'A', 'Data3' from dual
)
select listagg( item, ',') within group (order by item)
from elements group by code;
(You might also want to try 'Data1,Data2' as a single element. Watch out.
What you require is a query that breaks out each element separately. This can be done with
with element_list as
(select 'Data1,Data2,Data3' items from dual) -- get paraemter string
, parsed as
(select regexp_substr(items,'[^,]+',1,level) item
from element_list connect by regexp_substr(items,'[^,]+',1,level) is not null -- parse string to elements
)
The CTE "parsed" can now be used as table/view in your query.
This will not perform as well as querying directly with a parameter, but performance degradation is the cost of dynamic/flexible queries.
Also as set up this will NOT handle parameters which contain commas within an individual element. That would require much more code as you would have to determine/design how to keep the comma in those elements.

Oracle SQL - Select Max Integer Value from UserID String

I want to select the MAX value of the integer associated with the UserID in my Oracle database table to generate the next username for users with similar UserID.
The UserID contains values such as below. There is no fixed pattern of characters before the integer as the string is a username.
TKe10
TKe9
TKe12
TomKelly13
TomKelly9
PJames12
PJames7
I tried using the query below but it always gives TKe9 OR TomKelly9 OR PJames7 as the MAX value.
SELECT * FROM
(SELECT MAX(UserID) from PV_USERS
WHERE REGEXP_LIKE (UserID, '^'|| '<some_user_id>'|| '[^A-
Za-z][0-9]*'));
I have also tried using ORDER BY DESC WHERE ROWNUM<=1 but it also gives the same output.

You need to extract just the numeric part of the ID, which you can do with
regexp_substr(userid, '[0-9]*$')
and then convert that to a number before finding the maximum (otherwise you'll still be doing string comparison, and sorting 9 before 10):
max(to_number(regexp_substr(userid, '[0-9]*$')))
and you probably want to allow for the ID root you're checking to not exist at all yet, which you can do with nvl() or coalesce():
select coalesce(max(to_number(regexp_substr(userid, '[0-9]*$'))), 0) as max_num
from pv_users
where regexp_like(userid, '^'|| 'TomKelly'|| '[0-9]*');
MAX_NUM
----------
13
select coalesce(max(to_number(regexp_substr(userid, '[0-9]*$'))), 0) as max_num
from pv_users
where regexp_like(userid, '^'|| 'PJames'|| '[0-9]*');
MAX_NUM
----------
12
select coalesce(max(to_number(regexp_substr(userid, '[0-9]*$'))), 0) as max_num
from pv_users
where regexp_like(userid, '^'|| 'NewName'|| '[0-9]*');
MAX_NUM
----------
0
... and then add 1 and append back onto the root to get the next ID.
Depending on your business rules, you might want to make the filter case-insensitive.
You should be aware that two sessions performing this operation simultaneously will see the same result, so both would try to create the same ID, e.g. TomKelly14. You either need to serialise this generation operation, or include a fall back - like checking if you get a PK violation when you try to insert the new value into the table and repeating if that happens.

with temp as
(
select 'Tke10' userid from dual
union all
select 'Tke9' userid from dual
union all
select 'Tke12' userid from dual
union all
select 'Tomkelly13' userid from dual
union all
select 'Tomkelly9' userid from dual
union all
select 'Pjames12' userid from dual
union all
select 'Pjames7' userid from dual
)
select A||B from (
select
substr(userid,1,instr(userid,to_number(regexp_substr(userid,'\d+$')))-1) A
,max(to_number(regexp_substr(userid,'\d+$'))) B
from temp
group by substr(userid,1,instr(userid,to_number(regexp_substr(userid,'\d+$')))-1)
)
;

Trip time calculation in relational databases?

I had this question in mind and since I just discovered this site I decided to post it here.
Let's say I have a table with a timestamp and a state for a given "object" (generic meaning, not OOP object); is there an optimal way to calculate the time between a state and the next occurrence of another (or same) state (what I call a "trip") with a single SQL statement (inner SELECTs and UNIONs aren't counted)?
Ex: For the following, the trip time between Initial and Done would be 6 days, but between Initial and Review it would be 2 days.
2008-08-01 13:30:00 - Initial
2008-08-02 13:30:00 - Work
2008-08-03 13:30:00 - Review
2008-08-04 13:30:00 - Work
2008-08-05 13:30:00 - Review
2008-08-06 13:30:00 - Accepted
2008-08-07 13:30:00 - Done
No need to be generic, just say what SGBD your solution is specific to if not generic.

Here's an Oracle methodology using an analytic function.
with data as (
SELECT 1 trip_id, to_date('20080801 13:30:00','YYYYMMDD HH24:mi:ss') dt, 'Initial' step from dual UNION ALL
SELECT 1 trip_id, to_date('20080802 13:30:00','YYYYMMDD HH24:mi:ss') dt, 'Work' step from dual UNION ALL
SELECT 1 trip_id, to_date('20080803 13:30:00','YYYYMMDD HH24:mi:ss') dt, 'Review' step from dual UNION ALL
SELECT 1 trip_id, to_date('20080804 13:30:00','YYYYMMDD HH24:mi:ss') dt, 'Work' step from dual UNION ALL
SELECT 1 trip_id, to_date('20080805 13:30:00','YYYYMMDD HH24:mi:ss') dt, 'Review' step from dual UNION ALL
SELECT 1 trip_id, to_date('20080806 13:30:00','YYYYMMDD HH24:mi:ss') dt, 'Accepted' step from dual UNION ALL
SELECT 1 trip_id, to_date('20080807 13:30:00','YYYYMMDD HH24:mi:ss') dt, 'Done' step from dual )
select trip_id,
step,
dt - lag(dt) over (partition by trip_id order by dt) trip_time
from data
/
1 Initial
1 Work 1
1 Review 1
1 Work 1
1 Review 1
1 Accepted 1
1 Done 1
These are very commonly used in situations where traditionally we might use a self-join.

PostgreSQL syntax :
DROP TABLE ObjectState;
CREATE TABLE ObjectState (
object_id integer not null,--foreign key
event_time timestamp NOT NULL,
state varchar(10) NOT NULL,
--Other fields
CONSTRAINT pk_ObjectState PRIMARY KEY (object_id,event_time)
);
For given state find first folowing state of given type
select parent.object_id,parent.event_time,parent.state,min(child.event_time) as ch_event_time,min(child.event_time)-parent.event_time as step_time
from
ObjectState parent
join ObjectState child on (parent.object_id=child.object_id and parent.event_time<child.event_time)
where
--Starting state
parent.object_id=1 and parent.event_time=to_timestamp('01-Aug-2008 13:30:00','dd-Mon-yyyy hh24:mi:ss')
--needed state
and child.state='Review'
group by parent.object_id,parent.event_time,parent.state;
This query is not the shortest posible but it should be easy to understand and used as part of other queries :
List events and their duration for given object
select parent.object_id,parent.event_time,parent.state,min(child.event_time) as ch_event_time,
CASE WHEN parent.state<>'Done' and min(child.event_time) is null THEN (select localtimestamp)-parent.event_time ELSE min(child.event_time)-parent.event_time END as step_time
from
ObjectState parent
left outer join ObjectState child on (parent.object_id=child.object_id and parent.event_time<child.event_time)
where parent.object_id=4
group by parent.object_id,parent.event_time,parent.state
order by parent.object_id,parent.event_time,parent.state;
List current states for objects that are not "done"
select states.object_id,states.event_time,states.state,(select localtimestamp)-states.event_time as step_time
from
(select parent.object_id,parent.event_time,parent.state,min(child.event_time) as ch_event_time,min(child.event_time)-parent.event_time as step_time
from
ObjectState parent
left outer join ObjectState child on (parent.object_id=child.object_id and parent.event_time<child.event_time)
group by parent.object_id,parent.event_time,parent.state) states
where
states.object_id not in (select object_id from ObjectState where state='Done')
and ch_event_time is null;
Test data
insert into ObjectState (object_id,event_time,state)
select 1,to_timestamp('01-Aug-2008 13:30:00','dd-Mon-yyyy hh24:mi:ss'),'Initial' union all
select 1,to_timestamp('02-Aug-2008 13:40:00','dd-Mon-yyyy hh24:mi:ss'),'Work' union all
select 1,to_timestamp('03-Aug-2008 13:50:00','dd-Mon-yyyy hh24:mi:ss'),'Review' union all
select 1,to_timestamp('04-Aug-2008 14:30:00','dd-Mon-yyyy hh24:mi:ss'),'Work' union all
select 1,to_timestamp('04-Aug-2008 16:20:00','dd-Mon-yyyy hh24:mi:ss'),'Review' union all
select 1,to_timestamp('06-Aug-2008 18:00:00','dd-Mon-yyyy hh24:mi:ss'),'Accepted' union all
select 1,to_timestamp('07-Aug-2008 21:30:00','dd-Mon-yyyy hh24:mi:ss'),'Done';
insert into ObjectState (object_id,event_time,state)
select 2,to_timestamp('01-Aug-2008 13:30:00','dd-Mon-yyyy hh24:mi:ss'),'Initial' union all
select 2,to_timestamp('02-Aug-2008 13:40:00','dd-Mon-yyyy hh24:mi:ss'),'Work' union all
select 2,to_timestamp('07-Aug-2008 13:50:00','dd-Mon-yyyy hh24:mi:ss'),'Review' union all
select 2,to_timestamp('14-Aug-2008 14:30:00','dd-Mon-yyyy hh24:mi:ss'),'Work' union all
select 2,to_timestamp('15-Aug-2008 16:20:00','dd-Mon-yyyy hh24:mi:ss'),'Review' union all
select 2,to_timestamp('16-Aug-2008 18:02:00','dd-Mon-yyyy hh24:mi:ss'),'Accepted' union all
select 2,to_timestamp('17-Aug-2008 22:10:00','dd-Mon-yyyy hh24:mi:ss'),'Done';
insert into ObjectState (object_id,event_time,state)
select 3,to_timestamp('12-Sep-2008 13:30:00','dd-Mon-yyyy hh24:mi:ss'),'Initial' union all
select 3,to_timestamp('13-Sep-2008 13:40:00','dd-Mon-yyyy hh24:mi:ss'),'Work' union all
select 3,to_timestamp('14-Sep-2008 13:50:00','dd-Mon-yyyy hh24:mi:ss'),'Review' union all
select 3,to_timestamp('15-Sep-2008 14:30:00','dd-Mon-yyyy hh24:mi:ss'),'Work' union all
select 3,to_timestamp('16-Sep-2008 16:20:00','dd-Mon-yyyy hh24:mi:ss'),'Review';
insert into ObjectState (object_id,event_time,state)
select 4,to_timestamp('21-Aug-2008 03:10:00','dd-Mon-yyyy hh24:mi:ss'),'Initial' union all
select 4,to_timestamp('22-Aug-2008 03:40:00','dd-Mon-yyyy hh24:mi:ss'),'Work' union all
select 4,to_timestamp('23-Aug-2008 03:20:00','dd-Mon-yyyy hh24:mi:ss'),'Review' union all
select 4,to_timestamp('24-Aug-2008 04:30:00','dd-Mon-yyyy hh24:mi:ss'),'Work';

I don't think you can get that answer with one SQL statement as you are trying to obtain one result from many records. The only way to achieve that in SQL is to get the timestamp field for two different records and calculate the difference (datediff). Therefore, UNIONS or Inner Joins are needed.

I'm not sure I understand the question exactly, but you can do something like the following which reads the table in one pass then uses a derived table to calculate it. SQL Server code:
CREATE TABLE #testing
(
eventdatetime datetime NOT NULL,
state varchar(10) NOT NULL
)
INSERT INTO #testing (
eventdatetime,
state
)
SELECT '20080801 13:30:00', 'Initial' UNION ALL
SELECT '20080802 13:30:00', 'Work' UNION ALL
SELECT '20080803 13:30:00', 'Review' UNION ALL
SELECT '20080804 13:30:00', 'Work' UNION ALL
SELECT '20080805 13:30:00', 'Review' UNION ALL
SELECT '20080806 13:30:00', 'Accepted' UNION ALL
SELECT '20080807 13:30:00', 'Done'
SELECT DATEDIFF(dd, Initial, Review)
FROM (
SELECT MIN(CASE WHEN state='Initial' THEN eventdatetime END) AS Initial,
MIN(CASE WHEN state='Review' THEN eventdatetime END) AS Review
FROM #testing
) AS A
DROP TABLE #testing

It is probably easier if you have a sequence number as well as the time-stamp: in most RDBMSs you can create an auto-increment column and not change any of the INSERT statements. Then you join the table with a copy of itself to get the deltas
select after.moment - before.moment, before.state, after.state
from object_states before, object_states after
where after.sequence + 1 = before.sequence
(where the details of SQL syntax will vary according to which database system).

-- Oracle SQl
CREATE TABLE ObjectState
(
startdate date NOT NULL,
state varchar2(10) NOT NULL
);
insert into ObjectState
select to_date('01-Aug-2008 13:30:00','dd-Mon-rrrr hh24:mi:ss'),'Initial' union all
select to_date('02-Aug-2008 13:30:00','dd-Mon-rrrr hh24:mi:ss'),'Work' union all
select to_date('03-Aug-2008 13:30:00','dd-Mon-rrrr hh24:mi:ss'),'Review' union all
select to_date('04-Aug-2008 13:30:00','dd-Mon-rrrr hh24:mi:ss'),'Work' union all
select to_date('05-Aug-2008 13:30:00','dd-Mon-rrrr hh24:mi:ss'),'Review' union all
select to_date('06-Aug-2008 13:30:00','dd-Mon-rrrr hh24:mi:ss'),'Accepted' union all
select to_date('07-Aug-2008 13:30:00','dd-Mon-rrrr hh24:mi:ss'),'Done';
-- Days in between two states
select o2.startdate - o1.startdate as days
from ObjectState o1, ObjectState o2
where o1.state = 'Initial'
and o2.state = 'Review';

create table A (
At datetime not null,
State varchar(20) not null
)
go
insert into A(At,State)
select '2008-08-01T13:30:00','Initial' union all
select '2008-08-02T13:30:00','Work' union all
select '2008-08-03T13:30:00','Review' union all
select '2008-08-04T13:30:00','Work' union all
select '2008-08-05T13:30:00','Review' union all
select '2008-08-06T13:30:00','Accepted' union all
select '2008-08-07T13:30:00','Done'
go
--Find trip time from Initial to Done
select DATEDIFF(day,t1.At,t2.At)
from
A t1
inner join
A t2
on
t1.State = 'Initial' and
t2.State = 'Review' and
t1.At < t2.At
left join
A t3
on
t3.State = 'Initial' and
t3.At > t1.At and
t4.At < t2.At
left join
A t4
on
t4.State = 'Review' and
t4.At < t2.At and
t4.At > t1.At
where
t3.At is null and
t4.At is null
Didn't say whether joins were allowed or not. Joins to t3 and t4 (and their comparisons) let you say whether you want the earliest or latest occurrence of the start and end states (in this case, I'm asking for latest "Initial" and earliest "Review")
In real code, my start and end states would be parameters
Edit: Oops, need to include "t3.At < t2.At" and "t4.At > t1.At", to fix some odd sequences of States (e.g. If we removed the second "Review" and then queried from "Work" to "Review", the original query will fail)

I think that your steps (each record of your trip can be seen as a step) can be somewhere grouped together as part of the same activity. It is then possible to group your data on it, as, for example:
SELECT Min(Tbl_Step.dateTimeStep) as tripBegin, _
Max(Tbl_Step.dateTimeStep) as tripEnd _
FROM
Tbl_Step
WHERE
id_Activity = 'AAAAAAA'
Using this principle, you can then calculate other aggregates like the number of steps in the activity and so on. But you will not find an SQL way to calculate values like gap between 2 steps, as such a data does not belong either to the first or to the second step. Some reporting tools use what they call "running sums" to calculate such intermediate data. Depending on your objectives, this might be a solution for you.

I tried to do this in MySQL. You would need to use a variable since there is no rank function in MySQL, so it would go like this:
set #trip1 = 0; set #trip2 = 0;
SELECT trip1.`date` as startdate, datediff(trip2.`date`, trip1.`date`) length_of_trip
FROM
(SELECT #trip1 := #trip1 + 1 as rank1, `date` from trip where state='Initial') as trip1
INNER JOIN
(SELECT #trip2 := #trip2 + 1 as rank2, `date` from trip where state='Done') as trip2
ON rank1 = rank2;
I am assuming that you want to calculate the time between 'Initial' and 'Done' states.
+---------------------+----------------+
| startdate | length_of_trip |
+---------------------+----------------+
| 2008-08-01 13:30:00 | 6 |
+---------------------+----------------+

Ok, this is a bit beyond geeky, but I built a web application to track my wife's contractions just before we had a baby so that I could see from work when it was getting close to time to go to the hospital. Anyway, I built this basic thing fairly easily as two views.
create table contractions time_date timestamp primary key;
create view contraction_time as
SELECT a.time_date, max(b.prev_time) AS prev_time
FROM contractions a, ( SELECT contractions.time_date AS prev_time
FROM contractions) b
WHERE b.prev_time < a.time_date
GROUP BY a.time_date;
create view time_between as
SELECT contraction_time.time_date, contraction_time.prev_time, contraction_time.time_date - contraction_time.prev_time
FROM contraction_time;
This could be done as a subselect obviously as well, but I used the intermediate views for other things as well, and so this worked out well.