I am running a query to retrieve an integer but want to put a check for nulls. If null I want the query to return 0. How can I do that? I tried this below but it's not working
select NVL(A_COUNT, 0) from MYTABLE where VEH_YEAR = '2003';
If A_COUNT is null I want the query to return 0. In the above case I don't have a value 2003 in VEH_YEAR column. The query works if I have a value 2003 in VEH_YEAR column but A_COUNT is null.
Better version of your uery would be, using an Aggregate function like MAX before using NVL.
select NVL(MAX(A_COUNT),0) from MYTABLE where VEH_YEAR = '2003';
SELECT NVL((select A_COUNT from MYTABLE where VEH_YEAR = '2003'), 0) A_COUNT from dual;
This worked.
Related
I'm trying to Right join two table on a column named "compte"
I need to do an addition after. The problem is that some "compte" doesn't exist in one of the table and as a result, the addition return null instead of keeping the based value
Here's the query
SELECT t.compte,t.posdev+x.mnt
FROM (
SELECT compte,SUM(mntdev) as mnt FROM mvtc22
WHERE compte IN ('11510198451','00610198451','40010198451','40010198453','00610198461','00101980081','00101980094',
'00101980111','40010198461','40010198462','40010198466','40010198463')
AND datoper BETWEEN '01/01/22' AND '06/01/22'
GROUP BY compte
)x
RIGHT OUTER JOIN
(
SELECT c.compte,c.posdev
FROM v_sldoper c
WHERE c.compte IN ('11510198451','00610198451','40010198451','40010198453','00610198461','00101980081','00101980094',
'00101980111','40010198461','40010198462','40010198466','40010198463')
AND datpos = '31/12/21'
)t
ON t.compte = x.compte
And the results :
I'm expecting to keep the results from the second subquery if there's no "compte" in the first subquery.
Thanks In advance,
Alex
You are very close, the problem is that in oracle SQL the result of any value + null value is null, so you need to handle potential null values from each column before applying the + operator betwen them.
To solve the issue, you can apply functions like NVL or decode or even CASE WHEN for that purpose.
Below I use NVL function to solve it (I assume t.posdev column cannot contain null values, otherwise apply nvl function to both columns).
SELECT t.compte, t.posdev + NVL(x.mnt, 0)
FROM (
SELECT compte,SUM(mntdev) as mnt FROM mvtc22
WHERE compte IN ('11510198451','00610198451','40010198451','40010198453','00610198461','00101980081','00101980094',
'00101980111','40010198461','40010198462','40010198466','40010198463')
AND datoper BETWEEN '01/01/22' AND '06/01/22'
GROUP BY compte
)x
RIGHT OUTER JOIN
(
SELECT c.compte,c.posdev
FROM v_sldoper c
WHERE c.compte IN ('11510198451','00610198451','40010198451','40010198453','00610198461','00101980081','00101980094',
'00101980111','40010198461','40010198462','40010198466','40010198463')
AND datpos = '31/12/21'
)t
ON t.compte = x.compte
I have query in which I select records with data validation on table with AND Condition but only 1 Condition have no records so that it returns 0 rows. How to avoid this condition.
Query:
SELECT a.clientid, a.cnic_no, a.nrsp_status, b.projectid
FROM we_group_hof_k a, hof b
WHERE a.clientid IS NOT NULL
AND a.nrsp_status = 2
AND LENGTH(a.cnic_no) <=13
AND b.urn like '006%'
I found last Condition b.urn does not have 006%. So this query return 0 rows. I want if this condition have no records then show others records
Updated query:
INSERT INTO we_group_hof
(clientid, projectid, cnic_no, gendid, rid, mstatusid, village_id, ucid, cityid, disttid, nrsp_hofid, group_hof_id, nrsp_status, isenrolled
, cardstatus, dob, cardno)
SELECT a.clientid, a.cnic_no, a.gendid, a.rid, a.mstatusid, a.village_id, a.ucid, a.cityid, a.nrsp_hofid,
a.group_hof_id, a.nrsp_status, a.isenrolled, a.cardstatus, a.dob, LPAD(b.projectid,3,0), LPAD(b.disttid,3,0),to_char(max(b.cardno)+1)
FROM we_group_hof_k a, hof b
WHERE ((a.clientid IS NOT NULL
AND a.nrsp_status = 2
AND LENGTH(a.cnic_no) <=13
AND a.isenrolled = 'Y'
AND a.cardstatus = 'A'
AND a.dob <= sysdate
AND a.dob IS NOT NULL)
OR b.urn like '006%')
GROUP BY a.clientid, b.projectid, a.cnic_no, a.gendid, a.rid,
a.mstatusid, a.village_id, a.ucid, a.cityid, b.disttid, a.nrsp_hofid,
a.group_hof_id, a.nrsp_status, a.isenrolled, a.cardstatus, a.dob;
I tried with this query but this query did not execute and query executing not execute
It isn't clear if this is exactly what you want, but it's likely that an OR condition with proper parentheses will help you in selectively filtering the needed records.
..
WHERE
( a.clientid IS NOT NULL
AND a.nrsp_status = 2
AND LENGTH(a.cnic_no) <=13
)
OR b.urn like '006%'
I am just wondering if use = sign operator with sub-query instead of IN
Is it correct way ? and meet the oracle standard ?
Example
select column_name from my_table_1 where id = (select max(id) from my_table_2);
The Difference is related to the number of rows returned. If you have only one row returned from nested sql you may prefer both = or in operators. But if multiple rows returned from nested query, use in operator.
So, in your sql example you may prefer using any of the operators. Since, max functions returns only one row.
As you are fetching maximum value from subquery to compare with id, Both(= and IN )will work fine. But If you are trying to fetch more than one row then you have to use IN keyword.
If you have 1 result in sub query you are fine with using = sign, except when data type is wrong, for example , checking with same data type of dummy VARCHAR2(1)
select * from dual where 'X' = (select max(dual.dummy) from dual);
Is similar to using in (also same explain plain)
select * from dual where 'X' in (select max(dual.dummy) from dual);
But checking with different/wrong data type will result with exception ORA-01722 Invalid number
select * from dual where 1 =(select max(dual.dummy) from dual);
I have a query that I need for it to return a record even when there are no records. In the case where there are records, I simply want those records returned. On the other hand, when there are no records, I need it to still return a record but with the value for the "context" column (the GROUP BY column) equal to the value of the GROUP BY column that did not meet the criteria and a default value for aggregate function/column (e.g., 0). I tried a subquery:
SELECT
(
SELECT
CONTEXT,
SUM(VAL)
FROM
A_TABLE
WHERE
COL = 'absent'
GROUP BY
CONTEXT
)
FROM
DUAL;
but anything greater than one column in the subquery SELECT clause fails w/ a "too many values" message.
I also tried a UNION (with a little more context to more faithfully represent my situation):
SELECT
*
FROM
(
SELECT
CONTEXT,
SUM(VAL)
FROM
A_TABLE
WHERE
COL = 'absent'
GROUP BY
CONTEXT
UNION
SELECT
CONTEXT,
0
FROM
B_TABLE
)
AB_TABLE
INNER JOIN C_TABLE C -- just a table that I need to join to
ON
C.ID = AB_TABLE.C_ID
WHERE
C.ID = 10
AND ROWNUM = 1 -- excludes 2nd UNION subquery result when 1st returns record;
This one does work but I don't know why since the 2nd UNION subquery does not seem to be expressly connected w/ the first (I need the 2nd CONTEXT value to be the same as the 1st for the case where the 1st returns no records). The problem is that the real query does not return any records when I try to implement a similar strategy. I would like to see if there's a better way to approach this problem and perhaps get it to work for the real query (not included as it is too large and somewhat sensitive).
I am not sure I understand the question, but let's try.
I believe what you are saying is this. You have a table called A_TABLE, with columns CONTEXT, VAL, COL (and perhaps others as well).
You want to group by CONTEXT, and get the sum of VAL but only for those rows where COL = 'absent'. Otherwise you want to return a default value (let's say 0).
This can be done with conditional aggregation. The condition is in a CASE expression within the SUM, not in a WHERE clause (as you saw already, if you filter by COL='absent', in a WHERE clause, the query - past the WHERE clause - has no knowledge of the CONTEXT values that don't appear in any rows with COL = 'absent').
If the "default value" was NULL, you could do it like this:
select context, sum(case when col = 'absent' then value end) as val
from a_table
group by context
;
If the default value is anything other than NULL, the temptation may be to use NVL() around the sum. However, if VAL may be NULL, then it is possible that SUM(VAL) is NULL even when there are rows with COL = 'absent'. To address that possibility, you must leave the sum as NULL in those cases, and instead set the value to 0 (or whatever other "default value") only when there are NO rows with COL = 'absent'. Here is one way to do that. Still a standard "conditional" aggregate query:
select context,
case when count(case when col = 'absent' then 1 end) > 0
then sum(case when col = 'absent' then value end)
else 0 -- or whatever "default value" you must assign here
end as val
from a_table
group by context
;
Here's another way you could handle it that avoids the two additional tables (B_TABLE and C_TABLE).
SELECT context
, MAX(val)
FROM (
SELECT context
, SUM(val) as val
FROM a_table
WHERE col = 'absent'
GROUP BY context
UNION
SELECT context
, 0 as val
FROM a_table
) t
GROUP BY context
This assumes the default value you want to return is 0 and that any value in A_TABLE.VAL will be a positive integer.
http://sqlfiddle.com/#!4/c6ca0/20
SELECT b.context
, sum(a.val)
FROM b_table b
LEFT OUTER JOIN a_table a
ON a.context = b.context
AND a.col = 'absent'
GROUP BY b.context
I have two tables T_SUBJECTS (subject_id, date_of_birth) and T_ADMISSIONS (visit_id, subject_id, date_of_admission, age). I want to update the age column with the age at time of admission. I wrote the update query and get the "single row sub-query returns more than one row". I understand the error but thought the where exists clause will solve the problem. Below is the query.
UPDATE
t_admissions
SET
t_admissions.age =
(
SELECT
TRUNC(months_between(t_admissions.date_of_admission,
t_subjects.date_of_birth)/12)
FROM
t_admissions,
t_subjects
WHERE
t_admissions.subject_id = t_subjects.subject_id
AND t_admissions.age = 0
AND t_admissions.date_of_admission IS NOT NULL
AND t_subjects.date_of_birth IS NOT NULL
)
WHERE
EXISTS
(
SELECT
1
FROM
t_admissions, t_subjects
WHERE
t_admissions.subject_id = t_subjects.subject_id
);
The problem is that your subquery in the SET clause returns multiple rows.
Having a WHERE clause will only filter which records get updated and nothing else.
In addition, your where clause will either always return true or always return false.
You should look into how to properly do a correlated update:
https://stackoverflow.com/a/7031405/477563
A correlated update is what I need as suggested in the above link. See answer below.
UPDATE
(
SELECT
t_admissions.visit_id,
t_admissions.date_of_admission doa,
t_admissions.age age,
t_subjects.date_of_birth dob
FROM
t_admissions,
t_subjects
WHERE
t_admissions.subject_id = t_subjects.subject_id
AND t_admissions.age = 0
AND t_admissions.date_of_admission IS NOT NULL
AND t_subjects.date_of_birth IS NOT NULL
)
SET
age = TRUNC(months_between(doa,dob)/12);