Is it possible to create a conditional index on two columns?
CREATE UNIQUE INDEX idx_dup_wfc
ON WF_WORKFLOW_CLASS (CASE WHEN is_active = 1
THEN (NAME, DEPT_OWNER)
ELSE NULL
END)
returns ORA-00906: missing left parenthesis however the following works
CREATE UNIQUE INDEX idx_dup_wfc
ON WF_WORKFLOW_CLASS (CASE WHEN is_active = 1
THEN NAME
ELSE NULL
END)
Yes, but you have to perform a CASE per column:
CREATE UNIQUE INDEX idx_dup_wfc
ON WF_WORKFLOW_CLASS
(CASE WHEN is_active = 1 THEN NAME END
,CASE WHEN is_active = 1 THEN DEPT_OWNER END
)
(The ELSE in your code is superfluous).
Related
Hi I am building a v simple report as below; when I include the customer reference number and filter for another column (resolved time) being NULL then the number of incidents are reduced. (I know they exist within the database with the same filters)
(only INC1988464 is showing when more incidents should be showing)
Is there a way to test issues such as this in webi? Or a way to resolve this? Thanks in advance
Here is the sql used to make the report:
SELECT
'INC'||TRIM(to_char(ead_incident.incident,'0000000')),
ead_incident_credit.circuit_ref,
ead_incident_credit.customer_ref,
ead_incident_credit.data_rate,
ead_incident_credit.connection_type,
ead_incident_credit.completed_date,
ead_incident_credit.wholesaler_name,
ead_incident_credit.opened_datetime,
ead_incident_credit.resolved_datetime,
ead_incident_credit.resolution_details,
ead_incident_credit.resolution_duration_seconds,
ead_incident_credit.access_circuit_core_network,
ead_incident_credit.charge_amount,
ead_incident_credit.or_cost,
ead_incident_credit.sky_cost,
ead_incident_credit.service_credit_applicable,
ead_incident_credit.service_credit_due,
CASE WHEN COALESCE(COALESCE(ead_incident.actual_end_datetime,ead_incident.impact_end_datetime),ead_incident.resolved_datetime) IS NOT NULL THEN CASE WHEN ead_incident.impact_type = 'Full Outage' AND COALESCE(ead_incident.cause_classification,'') <> 'Resolved - No fault found' AND COALESCE(odwh_data.ead_within_sla('TTR',ead_incident.opened_datetime, COALESCE(COALESCE(ead_incident.actual_end_datetime,ead_incident.impact_end_datetime),ead_incident.resolved_datetime)),'f') = 'f' THEN 'Y' ELSE 'N' END ELSE NULL END,
CASE WHEN ead_incident.correlation = 't' THEN 'Y' ELSE 'N' END,
odwh_system.kpi_nextweek_startdate(),
odwh_system.kpi_currentweek_startdate()
FROM
odwh_data.ead_incident ead_incident INNER JOIN odwh_data.ead_incident_credit ead_incident_credit ON (ead_incident_credit.incident=ead_incident.incident)
WHERE
(
CASE WHEN COALESCE(COALESCE(ead_incident.actual_end_datetime,ead_incident.impact_end_datetime),ead_incident.resolved_datetime) IS NOT NULL THEN CASE WHEN ead_incident.impact_type = 'Full Outage' AND COALESCE(ead_incident.cause_classification,'') <> 'Resolved - No fault found' AND COALESCE(odwh_data.ead_within_sla('TTR',ead_incident.opened_datetime, COALESCE(COALESCE(ead_incident.actual_end_datetime,ead_incident.impact_end_datetime),ead_incident.resolved_datetime)),'f') = 'f' THEN 'Y' ELSE 'N' END ELSE NULL END = 'Y'
AND
(
CASE WHEN ead_incident.deleted = 't' THEN 'Y' ELSE 'N' END = 'N'
AND
(
CASE WHEN ead_incident.wholesaler = 't' THEN 'Y' WHEN ead_incident.wholesaler = 'f' THEN 'N' END = 'Y'
OR
CASE WHEN ead_incident.wholesaler = 't' THEN 'Y' WHEN ead_incident.wholesaler = 'f' THEN 'N' END Is Null
)
)
)
If you can create a free-hand SQL query which exhibits your issue like this...
SELECT
'INC1988464' AS [Incident Number]
, 'SKY-COLT-003' AS [Customer Reference]
, CONVERT (DATETIME, '2022-05-08 11:17:49') AS [Resovled Time]
UNION
SELECT
'INC1988464' AS [Incident Number]
, 'SKY-COLT-005' AS [Custome rReference]
, CONVERT (DATETIME, '2022-05-09 9:03:21') AS [Resovled Time]
UNION
SELECT
'INC1988464' AS [Incident Number]
, 'SKY-COLT-007' AS [Customer Reference]
, NULL AS [Resovled Time]
UNION
SELECT
'INC1988464' AS [Incident Number]
, 'SKY-COLT-009' AS [Customer Reference]
, CONVERT (DATETIME, '2022-05-09 10:17:02') AS [Resovled Time];
Then we can take that query, put it into a WebI report, replicate the issue, and possibly resolve it.
First and easiest thing to check. Do you have any filters already on your report page or are you starting on a brand new page? The filters may be against the page or the individual report block.
If you have, then remove them and see if the issue is resolved. Note that there may also be a ranking in there, returning the top 1 incidents.
If not, then there will be something in the report logic preventing the records from being returned. Comment out the where clauses and make sure to add the columns from the where clauses into your result set. From here you have two things to check:
1/ All rows are being returned
2/ You can see which rows are going to be filtered by your where clause based on what you see on your report based on your logic. You have nested case expressions which may not be doing what you expected for example.
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 am trying to run a simple query where I get a sum of gardeners who have zero support visits. I would like to add other cases, but first I would like to get this zero thing right. This is what I have come up with:
Gardener.from(Gardener.joins(:support_visits).group(:gardener_id).select("CASE WHEN count(gardener_id) = 0 THEN 1 END AS zero_count"),:t).select("sum(t.zero_count) as tot_zero_count")
Which gives me the following sql query:
SELECT sum(t.zero_count) as tot_zero_count
FROM
(
SELECT CASE WHEN count(gardener_id) = 0 THEN 1 END AS zero_count
FROM "gardeners" INNER JOIN "support_visits"
ON "support_visits"."gardener_id" = "gardeners"."id"
GROUP BY gardener_id
) t
The query runs but gives me nil.
Your current query uses count(gardener_id) = 0 which is never true because any group will have at least one record. Instead, you can LEFT JOIN the gardeners table to the support_visits table. Any gardener which does not appear in the support_visits table will not match to a visit, leaving a null value which you can then count.
SELECT SUM(CASE WHEN "support_visits"."gardener_id" IS NULL THEN 1 ELSE 0 END) AS zero_count
FROM "gardeners" LEFT JOIN "support_visits"
ON "support_visits"."gardener_id" = "gardeners"."id"
Here is the Ruby ActiveRecord code for this query:
Gardener.from(Gardener.joins("LEFT JOIN `support_visits` ON gardeners.id = support_visits.gardener_id").select("SUM(CASE WHEN "support_visits"."gardener_id" IS NULL THEN 1 ELSE 0 END) AS zero_count"))
I have a school 'project' to work on, which has some tables and one table needs to have a constraint which is not working out for me.
There are some tables like QUESTION, ANSWER and REACTION.
A reaction belongs with or a question or a answer but not both on the same time.
There by I have 2 rows:
question_id NUMBER,
answer_id NUMBER,
Both not null because the cant by null, but not on the same time.
I already made a constraint but isn't working..
/* CHECK if reaction belongs to an question or a answer NOT WORKING YET*/
CONSTRAINT CHECK_question_or_answer CHECK((answer_id != NULL AND question_id = NULL) OR (answer_id = NULL OR question_id != NULL))
Already tested the constraint and I can insert a value without a question_id or answer_id.
I hope it's a bit clear, if not, I am happy yo try explain myself better.
(still newby on SQL)
Thanks.
Your constraint:
CONSTRAINT CHECK_question_or_answer CHECK((answer_id != NULL AND profile_id = NULL) OR (answer_id = NULL OR profile_id != NULL))
Is always FALSE.
You need to use IS NULL or IS NOT NULL like:
CONSTRAINT CHECK_question_or_answer CHECK((answer_id IS NOT NULL AND profile_id IS NULL) OR (answer_id IS NULL OR profile_id IS NOT NULL))
This is because comparison operators != , = , > , <, combined with NULL produce NULL and are treated as false.
Demo:
SELECT 1
FROM dual
WHERE 1 IS NOT NULL;
SELECT 1
FROM dual
WHERE 1 != NULL;
From doc:
NULL values represent missing or unknown data. NULL values are used as
placeholders or as the default entry in columns to indicate that no
actual data is present. The NULL is untyped in SQL, meaning that it is
not an integer, a character, or any other specific data type.
Note that NULL is not the same as an empty data string or the
numerical value '0'. While NULL indicates the absence of a value, the
empty string and numerical zero both represent actual values.
While a NULL value can be assigned, it can not be equated with
anything, including itself.
Because NULL does not represent or equate to a data type, you cannot
test for NULL values with any comparison operators, such as =, <, or
<>.
The IS NULL and IS NOT NULL operators are used to test for NULL
values.
Do it the other way around. Put the id of the main table in the others like that
question table
--------------
id
text
...
answers table
-------------
id
question_id
text
...
reactions table
---------------
id
question_id
text
...
And question_id is never null. Then you can use a left join to get the results from both tables - one of them will have no results.
select *
from questions q
left join answers a on a.question_id = q.id
left join reactions r on r.question_id = q.id
While #lad2025s answer is good for two columns, if you wanted to extend the method to more than two it can get a bit cumbersome.
A flexible alternative is:
check ((case when answer_id is null then 0 else 1 end +
case when question_id is null then 0 else 1 end ) = 1)
It extends well to checking for a particular count of null (or non-null) values for an arbitrary number of columns.
For example, if you had column_1, column_2, column3, and column_4, and wanted at least 1 of them to be non-null, then:
check ((case when column_1 is null then 0 else 1 end +
case when column_2 is null then 0 else 1 end +
case when column_3 is null then 0 else 1 end +
case when column_4 is null then 0 else 1 end ) >= 1)
I have a table and i have to check a particular column in null or has value.
Lets say the column name is order_price.
If i just check where order_price is null then this also includes records that are not in the table too.
For example i have order_id = 1 whose order_price is null and i have order_id = 2 which does not exist in order table. So instead of a where condition to check whether order_price is null, i want to know whether the column is null or the record does not exist.
I'm doing outer join on this table so i cannot map the primary keys of another table. I am using Oracle.
Thanks
SELECT o.*,
od.order_price,
CASE
WHEN od.order_id IS NULL THEN
'Not exists'
WHEN od.order_price IS NULL THEN
'Exists, IS NULL'
ELSE
'Exists, IS NOT NULL'
END AS nullness
FROM orders o
LEFT JOIN
order_data od
ON od.order_id = o.id
Instead of a Join , you can use the "EXISTS / NOT EXISTS" keyword and a subquery.
e.g.
SELECT parent.*
FROM parent
WHERE EXISTS (SELECT 1
FROM child
WHERE child.id_parent = parent.id AND child.somecolumn IS NULL)
You can play with "exists / not exists" depending on whether you want or don't want the predicate to match.