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.
Related
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.
My code from SQL Server:
SELECT ESTAGIO.SK_ESTAGIO, ISNULL(count(ESTAGIO.SK_ESTAGIO), 0) as how_many
from ESTAGIO
left join ESTAGIARIO
on ESTAGIARIO.SK_ESTAGIO = ESTAGIO.SK_ESTAGIO
group by
ESTAGIO.SK_ESTAGIO
When "ESTAGIO.SK_ESTAGIO" doesn't exist in the table "ESTAGIARIO" it returns 1 instead of 0, I already tried to use ISNULL(), NULLIF() and COALESCE() and still couldn't find the problem that is making the query above returning 1 when it should be 0.
You are counting the wrong field. Do it like this, taking the field from the outer joined table ESTAGIARIO (not from ESTAGIO):
SELECT ESTAGIO.SK_ESTAGIO, Count(ESTAGIARIO.SK_ESTAGIO) as how_many
from ESTAGIO
left join ESTAGIARIO
on ESTAGIARIO.SK_ESTAGIO = ESTAGIO.SK_ESTAGIO
group by
ESTAGIO.SK_ESTAGIO
BTW, count can never return null.
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);
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).
SELECT (h.horario), h.codigo
FROM horarios as h
JOIN horario_turma as h_t
ON(h.codigo != h_t.cd_horario)
WHERE h_t.cd_turma = 'HTJ009'
AND h_t.cd_dia = 2
AND h.cd_turno = 1
I'm trying to figure out if there's a possibility to get the h.cd_turnovalue from another table and use in the same query, beacuse this value is gonna be variable. So, I'd have to get this value from a query, then pass the value to PHP and do another query with this value. Is there a way to do that in the same query?
There's a table called turmas(codigo, cd_turno). I'll have the codigovalue, in this case HTJ009, and I'd like to select the cd_turno value.
Query used to get the value:
SELECT cd_turno FROM turmas WHERE codigo='HTJ009'
You can use a subquery, like so:
SELECT (h.horario), h.codigo
FROM horarios as h
JOIN horario_turma as h_t
ON(h.codigo != h_t.cd_horario)
WHERE h_t.cd_turma = 'HTJ009'
AND h_t.cd_dia = 2
AND h.cd_turno = (SELECT cd_turno FROM turmas WHERE codigo='HTJ009')
In this case, remember that it is important for the subquery to return only one result, otherwise you'll encounter an error. If you do see such an error, you may have to tweak the subquery to ensure only one result is returned.
Check this out for Postgres subquery documentation
SELECT (h.horario), h.codigo
FROM horarios as h
JOIN horario_turma as h_t
ON(h.codigo = h_t.cd_horario)
WHERE h_t.cd_turma = 'HTJ009'
AND h_t.cd_dia = 2
AND h.cd_turno = 1 and h_t.cd_horario is null