Two similar queries and different result.

Question

Hi! I have a problem and
with
sc as (select * from nc_objects where object_type_id = 9122942307013185081 and project_id=9062345122013900768),
cid as (select sccid.value AS CIRCUIT_ID,sc.description AS DESCRIPTION
from sc, nc_params sccid
where sccid.object_id = sc.object_id and sccid.attr_id = 9122948792013185590),
caloc as ( select
(*select value from nc_params sccid where sccid.object_id = sc.object_id and sccid.attr_id = 9122948792013185590*) as CIRCUIT_ID,
(select sl.name from nc_objects sl join nc_references scr on sl.object_id = scr.reference
where scr.attr_id = 3090562190013347600 and scr.object_id = sc.object_id ) as ALOCATION
from sc),
cbloc as ( select
(select value from nc_params sccid where sccid.object_id = sc.object_id and sccid.attr_id = 9122948792013185590) as CIRCUIT_ID,
(select sl.name from nc_objects sl join nc_references scr on sl.object_id = scr.reference
where scr.attr_id = 3090562190013347601 and scr.object_id = sc.object_id ) as BLOCATION
from sc)
select cid.CIRCUIT_ID,cid.DESCRIPTION,ALOCATION,BLOCATION from (
cid
join caloc on cid.CIRCUIT_ID = caloc.CIRCUIT_ID and ALOCATION is not null
join cbloc on cid.CIRCUIT_ID = cbloc.CIRCUIT_ID and BLOCATION is not null
it` returns and`s all ok!
ID desc aloc bloc
101     TEST1     AHAS     AGUS
102     TEST2     AKRE     AMJY
103     TEST3     AMJS     ASSE
109     TEST9     BAIA     AKIB
5     (null)     WELA AGUS
We have "sc as (select * from nc_objects where object_type_id = 9122942307013185081 and project_id=9062345122013900768)"
and identical subquery on caloc and cbloc
"select value from nc_params sccid where sccid.object_id = sc.object_id and sccid.attr_id = 9122948792013185590"
If i change query on
with
sc as (select * from nc_objects where object_type_id = 9122942307013185081 and project_id=9062345122013900768),
cid as (select sccid.value AS CIRCUIT_ID,sc.description AS DESCRIPTION
from sc, nc_params sccid
where sccid.object_id = sc.object_id and sccid.attr_id = 9122948792013185590),
caloc as ( select
*(select CIRCUIT_ID from cid) as CIRCUIT_ID,*
(select sl.name from nc_objects sl join nc_references scr on sl.object_id = scr.reference
where scr.attr_id = 3090562190013347600 and scr.object_id = sc.object_id ) as ALOCATION
from sc),
cbloc as ( select
(select value from nc_params sccid where sccid.object_id = sc.object_id and sccid.attr_id = 9122948792013185590) as CIRCUIT_ID,
(select sl.name from nc_objects sl join nc_references scr on sl.object_id = scr.reference
where scr.attr_id = 3090562190013347601 and scr.object_id = sc.object_id ) as BLOCATION
from sc)
select cid.CIRCUIT_ID,cid.DESCRIPTION,ALOCATION,BLOCATION from (
cid
join caloc on cid.CIRCUIT_ID = caloc.CIRCUIT_ID and ALOCATION is not null
join cbloc on cid.CIRCUIT_ID = cbloc.CIRCUIT_ID and BLOCATION is not null
query result will be:
ORA-01427: single-row subquery returns more than one row
01427. 00000 - "single-row subquery returns more than one row"
*Cause:   
*Action:
Can you explain why so ?
Edited by: user12031606 on 07.05.2010 2:31
Edited by: user12031606 on 07.05.2010 2:32

Answer 1

Hi,
Welcome to the forum!
Whenever you post code, format it to show the extent of sub-queries, and the clauses in each one.
Type these 6 characters:
\(all small letters, inside curly brackets) before and after each section of formatted test; if you don't, this site will compress the spaces.
It also helps it you reduce your query as much as possible.  For example, I think you're only asking about the sub-query called caloc, so just post caloc as if that were the entire query:select     ( select CIRCUIT_ID
     from cid
     )                as CIRCUIT_ID,
     ( select sl.name
     from nc_objects          sl
     join nc_references      scr on sl.object_id = scr.reference
     where scr.attr_id      = 3090562190013347600
     and scr.object_id      = sc.object_id
     )                as ALOCATION
from sc
This makes it much cleared that the query will produce 2 columns, called circuit_id and alocation.
Compare the query above with the query below:SELECT     object_id,
     'Okay'
FROM     sc
The basic structure is the same: both queries produce two columns, and both queries produce one row of output for every row that is in the sc table.
The only difference is the two items in the SELECT clause.
The second query has a column from the table as its first column, and a literal for its second column; those are just two of the kinds of things you can have in a SELECT clause.  another thing you can have there is a +Scalar Sub-Query+ , a complete query enclosed in parentheses that produces exactly one column and at most one row.   If a scalar sub-query produces more than one row, then you get the run-time error: "ORA-01427: single-row subquery returns more than one row", as you did.
A scalar sub-query always takes the place of a single value: "scalar" means "having only one value".  In the first example above, the main query is supposed to produce one row of output for every row in sc.  How can it do that if some of the columns themselves contain multiple rows?
I don't know what your tables are like, or what output yu want to get from thiose tables.
If you'd like help getting certain results from your tables, then post CREATE TABLE and INSERT statements for a little sample data, and the resutls you want to get from that sample data.  A scalar sub-query may help getting those results, or it may not.