I need to update a column based on the results of a subquery. If the subquery returns results for that column then the columns must be updated, is the query returns no results for that column then I need to update with 0.
I do not know where to place the subquery and how to combine it with the CASE statement. This is what I thought but the syntax is not correct. Can anybody help please?
(SELECT datazones.ogc_fid, count(*) as total
FROM suppliersnew suppliers, datazone_report_resupply datazones
WHERE St_contains(datazones.geom, suppliers.geometry) AND (suppliers.status = 'Under construction' OR
suppliers.status = 'Unknown' OR suppliers.status = 'Operational') GROUP by datazones.ogc_fid ORDER BY total ASC) sources
UPDATE datazone_report_resupply
SET es_actual =
CASE
WHEN datazone_report_resupply.ogc_fid = sources.ogc_fid THEN sources.total
ELSE 0
END
The query is a little hard to follow, because the aggregation is on the outer column (this is unusual). However, you don't need aggregation or order by. You only seem to care whether a row exists.
I think the logic is:
UPDATE datazone_report_resupply r
SET es_actual =
(CASE WHEN EXISTS (SELECT 1
FROM suppliersnew s
WHERE St_contains(r.geom, s.geometry) AND
s.status IN ('Under construction', 'Unknown', 'Operational')
)
THEN 1 ELSE 0
END);
Related
So I'm trying to put a subquery within a CASE statement. The subquery itself is working fine, but if I put it in another code it can't process. What can I do best to solve?
CASE WHEN dbo.T1.TYPE = 0
THEN dbo.Data.QTY * dbo.Data.SALESPRICE
ELSE
CASE WHEN dbo.T1.TYPE = 1
THEN dbo.Data.QTY *
(
SELECT dbo.Data.ID,
CASE WHEN SUM(dbo.Data.QTY) = 0
THEN SUM(dbo.Data.SALESPRICE)
ELSE SUM(dbo.Data.SALESPRICE) / SUM(dbo.Data.QTY)
END AS REVph
FROM dbo.Data LEFT OUTER JOIN
dbo.T1ON dbo.Data.ID = dbo.T1.ID
WHERE (dbo.T1.TYPE = 1)
GROUP BY dbo.Data.ID
)
ELSE 0
END
END
You are using a subquery in a context where a single value is allowed. Such a subquery is called a scalar subquery.
However, the subquery is returning more than one column. That is not allowed. A scalar subquery can only return one column and at most one row.
Your question is rather unclear on what you want to accomplish, so I can only explain the problem that you are having.
Case: I have a stored procedure in where I got all the information of a table.
I have 2 parameters in order to set the Where clause but one of those could be
0.
Question: How do I do a Case When or an If in my Where clause depending on my parameter value?
I want to apply the where clause only if the value is different from 0
if is 0 I don't want to do it.
Code:
#ID_ORDER,
#ID_SUPPLIER
Select *
From Orders ord
where #ID_SUPPLIER = ord.ID_SUPPLIER
AND CASE WHEN #ID_ORDER = 0 THEN ord.ID_ORDER = #ID_ORDER END
You don't. You just use and and or:
select *
from Orders ord
where ord.ID_SUPPLIER = #ID_SUPPLIER) and
(ord.ID_ORDER = #ID_ORDER or #ID_ORDER = 0);
Note that the logic you are attempting is backwards. This only applies the filter on id_order when the value is not 0.
I have been writing a query that allows me to select and count rows for specific product id's and shipment types.
Within this data, what I am now trying to achieve is count which rows have a specific field populated (second member name) and which have not. Then return this as a separate column in my query results.
Here's the query which I have written:
select count(job.JobID) as itemsCount, Lookup_Pack.PackDescription, Lookup_Pack.PackCode, Lookup_Pack.ID, job.shipping,
CASE
WHEN Job.secondMemForename <> '' THEN count(job.JobID)
ELSE 0
END AS [Extra card count]
from job
inner join Lookup_Pack on Lookup_Pack.ID = job.packTypeID
where Lookup_Pack.PackType = 'REN'
AND job.createDate >= '2015-06-01' and Job.createDate <= '2015-06-30'
GROUP BY Lookup_Pack.PackDescription, Lookup_Pack.PackCode, Lookup_Pack.ID, Job.shipping
If I run this query, I get an error returned as I am not grouping by Job.secondMemForename:
[FreeTDS][SQL Server]Column 'job.secondMemForename' is invalid in the
select list because it is not contained in either an aggregate
function or the GROUP BY clause.
although Job.secondMemForename does not form part of the query results.
I have subsequently added this field to the GROUP BY statement, the problem with this is that the data returned for all rows where the CASE applies is un-grouped as the Job.secondMemForename is different for all of them.
Any idea how I can resolve this?
Thanks.
Steeve.
Change Count() to Sum() and add it before CASE
SUM (CASE WHEN Job.secondMemForename <> '' THEN 1 END) AS [Extra card count]
I hve to display several cell values into one cell. So I am using this query:
select LISTAGG(fc.DESCRIPTION, ';'||chr(10))WITHIN GROUP (ORDER BY fc.SWITCH_NAME) AS DESCRIP from "ORS".SWITCH_OPERATIONS fc
group by fc.SWITCH_NAME
It is working fine. But when I am merging this with my main(complete) query then I am getting the error as: Error code 1427, SQL state 21000: ORA-01427: single-row subquery returns more than one row
Here is my complete query:
SELECT
TRACK_EVENT.LOCATION,
TRACK_EVENT.ELEMENT_NAME,
(select COUNT(*) from ORS.TRACK_EVENT b where (b.ELEMENT_NAME = sw.SWITCH_NAME)AND (b.ELEMENT_TYPE = 'SWITCH')AND (b.EVENT_TYPE = 'I')AND (b.ELEMENT_STATE = 'NORMAL' OR b.ELEMENT_STATE = 'REVERSE'))as COUNTER,
(select COUNT(*) from ORS.SWITCH_OPERATIONS fc where TRACK_EVENT.ELEMENT_NAME = fc.SWITCH_NAME and fc.NO_CORRESPONDENCE = 1 )as FAIL_COUNT,
(select MAX(cw.COMMAND_TIME) from ORS.SWITCH_OPERATIONS cw where ((TRACK_EVENT.ELEMENT_NAME = cw.SWITCH_NAME) and (cw.NO_CORRESPONDENCE = 1)) group by cw.SWITCH_NAME ) as FAILURE_DATE,
(select LISTAGG(fc.DESCRIPTION, ';'||chr(10))WITHIN GROUP (ORDER BY fc.SWITCH_NAME) AS DESCRIP from "ORS".SWITCH_OPERATIONS fc
group by fc.SWITCH_NAME)
FROM
ORS.SWITCH_OPERATIONS sw,
ORS.TRACK_EVENT TRACK_EVENT
WHERE
sw.SEQUENCE_ID = TRACK_EVENT.SEQUENCE_ID
Not only are subqueries in the SELECT list required to return exactly one row (or any time they're used for a singular comparison, like <, =, etc), but their use in that context tends to make the database execute them RBAR - Row-by-agonizing-row. That is, they're slower and consume more resources than they should.
Generally, unless the result set outside the subquery contains only a few rows, you want to construct subqueries as part of a table-reference. Ie, something like:
SELECT m.n, m.z, aliasForSomeTable.a, aliasForSomeTabe.bSum
FROM mainTable m
JOIN (SELECT a, SUM(b) AS bSum
FROM someTable
GROUP BY a) aliasForSomeTable
ON aliasForSomeTable.a = m.a
This benefits you in other ways to - it's easier to get multiple columns out of the same table-reference, for example.
Assuming that LISTAGG(...) can be included with other aggregate functions, you can change your query to look like this:
SELECT Track_Event.location, Track_Event.element_name,
Counted_Events.counter,
Failure.fail_count, Failure.failure_date, Failure.descrip
FROM ORS.Track_Event
JOIN ORS.Switch_Operations
ON Switch_Operations.sequence_id = Track_Event.sequence_id
LEFT JOIN (SELECT element_name, COUNT(*) AS counter
FROM ORS.Track_Event
WHERE element_type = 'SWITCH'
AND event_type = 'I'
AND element_state IN ('NORMAL', 'REVERSE')
GROUP BY element_name) Counted_Events
ON Counted_Events.element_name = Switch_Operations.swicth_name
LEFT JOIN (SELECT switch_name,
COUNT(CASE WHEN no_correspondence = 1 THEN '1' END) AS fail_count,
MAX(CASE WHEN no_correspondence = 1 THEN command_time END) AS failure_date,
LISTAGG(description, ';' || CHAR(10)) WITHIN GROUP (ORDER BY command_time) AS descrip
FROM ORS.Switch_Operations
GROUP BY switch_name) Failure
ON Failure.switch_name = Track_Event.element_name
This query was written to (attempt to) preserve the semantics of your original query. I'm not completely sure that's what you actually need but without sample starting data and desired results, I have no way to tell how else to improve this. For instance, I'm a little suspicious of the need of Switch_Operations in the outer query, and the fact that LISTAGG(...) is run over row where no_correspondence <> 1. I did change the ordering of LISTAGG(...), because the original column would not have done anything (because the order way the same as the grouping), so would not have been a stable sort.
Single-row subquery returns more than one row.
This error message is self descriptive.
Returned field can't have multiple values and your subquery returns more than one row.
In your complete query you specify fields to be returned. The last field expects single value from the subquery but gets multiple rows instead.
I have no clue about the data you're working with but either you have to ensure that subquery returns only one row or you have to redesign the wrapping query (possibly using joins when appropriate).
I have the following sql statement and I want to update a field on the rows returned from the select statement. Is this possible with my select? The things I have tried are not giving me the desired results:
SELECT
Flows_Flows.FlowID,
Flows_Flows.Active,
Flows_Flows.BeatID,
Flows_Flows.FlowTitle,
Flows_Flows.FlowFileName,
Flows_Flows.FlowFilePath,
Flows_Users.UserName,
Flows_Users.DisplayName,
Flows_Users.ImageName,
Flows_Flows.Created,
SUM(CASE WHEN [Like] = 1 THEN 1 ELSE 0 END) AS Likes,
SUM(CASE WHEN [Dislike] = 1 THEN 1 ELSE 0 END) AS Dislikes
FROM Flows_Flows
INNER JOIN Flows_Users ON Flows_Users.UserID = Flows_Flows.UserID
LEFT JOIN Flows_Flows_Likes_Dislikes ON
Flows_Flows.FlowID=Flows_Flows_Likes_Dislikes.FlowID
WHERE Flows_Flows.Active = '1' AND Flows_Flows.Created < DATEADD(day, -60, GETDATE())
Group By Flows_Flows.FlowID, Flows_Flows.Active, Flows_Flows.BeatID,
Flows_Flows.FlowTitle, Flows_Flows.FlowFileName, Flows_Flows.FlowFilePath,
Flows_Users.UserName, Flows_Users.DisplayName, Flows_Users.ImageName,
Flows_Flows.Created
Having SUM(CASE WHEN [Like] = 1 THEN 1 ELSE 0 END) = '0' AND SUM(CASE WHEN [Dislike] = 1
THEN 1 ELSE 0 END) >= '0'
This select statement returns exactly what I need but I want to change the Active field from 1 to 0.
yes - the general structure might be like this: (note you don't declare your primary key)
UPDATE mytable
set myCol = 1
where myPrimaryKey in (
select myPrimaryKey from mytable where interesting bits happen here )
Because you haven't made your question more clear in what result you want to achieve, I'll provide an answer with my own assumptions.
Assumption
You have a select statement that gives you stuffs, and it works as desired. What you want it to do is to make it return results and update those selected rows on the fly - basically like saying "find X, tell me about X and make it Y".
Anwser
If my assumption is correct, unfortunately I don't think there is any way you can do that. A select does not alter the table, it can only fetch information. Similarly, an update does not provide more detail than the number of rows updated.
But don't give up yet, depending on the result you want to achieve, you have alternatives.
Alternatives
If you just want to update the rows that you have selected, you can
simply write an UPDATE statement to do that, and #Randy has provided
a good example of how it will be written.
If you want to reduce calls to server, meaning you want to make just
one call to the server and get result, as well as to update the
rows, you can write store procedures to do that.
Store procedures are like functions you wrote in programming languages. It essentially defines a set of sql operations and gives them a name. Each time you call that store procedure, the set of operations gets executed with supplied inputs, if any.
So if you want to learn more about store procedures you can take a look at:
http://www.mysqltutorial.org/introduction-to-sql-stored-procedures.aspx
If I understand correctly you are looking for a syntax to be able to select the value of Active to be 0 if it is 1. The syntax for something like that is
SELECT
Active= CASE WHEN Active=1 THEN 0 ELSE Active END
FROM
<Tables>
WHERE
<JOIN Conditions>