I currently want to combine two SQL queries into one. This is a bit similar to SQL: Taking the result of of query and using it another - combine. Suppose there are two queries:
SQL Statement
1.) SELECT *
FROM (SELECT B.example1
FROM EXAMPLE1A A
INNER JOIN EXAMPLE1B B ON A.ID = B.ID
WHERE A.ABC ='ABC'
ORDER BY A.ORDER_BY ) as colstate
2.) SELECT colstate
FROM EXAMPLE_TABLE
WHERE EFG LIKE '%'
AND BGTHAN >= '1'
AND SMTHAN <= '100'
ORDER BY ORDER_BY ASC
I want to use the result in query 1.) as the colstate (column statement) in query 2.). But:
What Have I tried is:
SELECT (SELECT B.example1
FROM EXAMPLE1A A
INNER JOIN EXAMPLE1B B
ON A.ID = B.ID
WHERE A.ABC ='ABC'
ORDER BY A.ORDER_BY )
FROM EXAMPLE_TABLE
WHERE EFG LIKE '%'
AND BGTHAN >= '1'
AND SMTHAN <= '100'
ORDER BY ORDER_BY ASC
And it turns out to be Error: Scalar subquery is only allowed to return a single row, how should I replace the "=" into "IN"? Or is my statement totally wrong?
"Combine two queries into one" - that's not a good specs. Try to find out what exactly you want to get as a FLAT 2-dimensional table, think of nested SELECTs as of nested loops where the inner one can only set a single value for parent's row. Like this:
[Outer loop - parent row]
[Inner loop - children rows]
// all you can do here is change a single parent's field to anything
// like constant/sum/avg/topmost/ugly-subquery-returning-a-single-result
[/Inner loop]
[/Outer loop]
The error says that query you are using as column statement must return at most a single row.
It should probably look something like this:
SELECT (SELECT B.example1
FROM EXAMPLE1A A
INNER JOIN EXAMPLE1B B
ON A.ID = B.ID
WHERE A.ABC ='ABC'
AND A.SOME_COLUMN = E.SOMECOLUMN // retrieve only relevant data for this row
ORDER BY A.ORDER_BY )
FROM EXAMPLE_TABLE E
WHERE EFG LIKE '%'
AND BGTHAN >= '1'
AND SMTHAN <= '100'
ORDER BY ORDER_BY ASC
Related
I am comparing every row of a table I have with every other row to find the minimum distance. I also want to add two columns one called "closest_distance", and the other "id_of_the_closest_distance".
I know that I need to do this in two steps: one- update the first row, and two- evaluate the second row based on the first.
I have a query that gives me the closest distance as below:
SELECT DISTINCT ON (a.id)
a.id,
(SELECT
MIN(ST_HausdorffDistance(a.the_geom, b.the_geom))
FROM
gridareas AS b
WHERE
b.id != a.id
)
FROM gridareas AS a;
However I cannot use a simple
UPDATE tablename SET colname = expression;
and use the query above as the expression, because
ERROR: subquery must return only one column
LINE 5: (SELECT DISTINCT ON (a.id)
On the other hand, the subquery cannot return both a.id and the MIN(ST_HausdorffDistance()).
How should I proceed to update this column?
Is this what you want?
update gridareas ga
set (closest_id, closest_dist) =
(select gs2.id, ST_HausdorffDistance(ga.the_geom, ga2.the_geom) as dist, ga2.id
from gridareas ga2
where ga2.id <> ga.id
order by ST_HausdorffDistance(ga.the_geom, ga2.the_geom)
limit 1
);
Not exactly, but it helped a lot, thanks!
This is what fixed my problem:
UPDATE
gridareas AS a
SET
(hausdorffdistance_to_closest_geom) =
(SELECT
MIN(ST_HausdorffDistance(a.the_geom, b.the_geom))
FROM
gridareas AS b
WHERE
b.id != a.id
);
I have a simple SQL table containing some values, for example:
id | value (table 'values')
----------
0 | 4
1 | 7
2 | 9
I want to iterate over these values, and use them in a query like so:
SELECT value[0], x1
FROM (some subquery where value[0] is used)
UNION
SELECT value[1], x2
FROM (some subquery where value[1] is used)
...
etc
In order to get a result set like this:
4 | x1
7 | x2
9 | x3
It has to be in SQL as it will actually represent a database view. Of course the real query is a lot more complicated, but I tried to simplify the question while keeping the essence as much as possible.
I think I have to select from values and join the subquery, but as the value should be used in the subquery I'm lost on how to accomplish this.
Edit: I oversimplified my question; in reality I want to have 2 rows from the subquery and not only one.
Edit 2: As suggested I'm posting the real query. I simplified it a bit to make it clearer, but it's a working query and the problem is there. Note that I have hardcoded the value '2' in this query two times. I want to replace that with values from a different table, in the example table above I would want a result set of the combined results of this query with 4, 7 and 9 as values instead of the currently hardcoded 2.
SELECT x.fantasycoach_id, SUM(round_points)
FROM (
SELECT DISTINCT fc.id AS fantasycoach_id,
ffv.formation_id AS formation_id,
fpc.round_sequence AS round_sequence,
round_points,
fpc.fantasyplayer_id
FROM fantasyworld_FantasyCoach AS fc
LEFT JOIN fantasyworld_fantasyformation AS ff ON ff.id = (
SELECT MAX(fantasyworld_fantasyformationvalidity.formation_id)
FROM fantasyworld_fantasyformationvalidity
LEFT JOIN realworld_round AS _rr ON _rr.id = round_id
LEFT JOIN fantasyworld_fantasyformation AS _ff ON _ff.id = formation_id
WHERE is_valid = TRUE
AND _ff.coach_id = fc.id
AND _rr.sequence <= 2 /* HARDCODED USE OF VALUE */
)
LEFT JOIN fantasyworld_FantasyFormationPlayer AS ffp
ON ffp.formation_id = ff.id
LEFT JOIN dbcache_fantasyplayercache AS fpc
ON ffp.player_id = fpc.fantasyplayer_id
AND fpc.round_sequence = 2 /* HARDCODED USE OF VALUE */
LEFT JOIN fantasyworld_fantasyformationvalidity AS ffv
ON ffv.formation_id = ff.id
) x
GROUP BY fantasycoach_id
Edit 3: I'm using PostgreSQL.
SQL works with tables as a whole, which basically involves set operations. There is no explicit iteration, and generally no need for any. In particular, the most straightforward implementation of what you described would be this:
SELECT value, (some subquery where value is used) AS x
FROM values
Do note, however, that a correlated subquery such as that is very hard on query performance. Depending on the details of what you're trying to do, it may well be possible to structure it around a simple join, an uncorrelated subquery, or a similar, better-performing alternative.
Update:
In view of the update to the question indicating that the subquery is expected to yield multiple rows for each value in table values, contrary to the example results, it seems a better approach would be to just rewrite the subquery as the main query. If it does not already do so (and maybe even if it does) then it would join table values as another base table.
Update 2:
Given the real query now presented, this is how the values from table values could be incorporated into it:
SELECT x.fantasycoach_id, SUM(round_points) FROM
(
SELECT DISTINCT
fc.id AS fantasycoach_id,
ffv.formation_id AS formation_id,
fpc.round_sequence AS round_sequence,
round_points,
fpc.fantasyplayer_id
FROM fantasyworld_FantasyCoach AS fc
-- one row for each combination of coach and value:
CROSS JOIN values
LEFT JOIN fantasyworld_fantasyformation AS ff
ON ff.id = (
SELECT MAX(fantasyworld_fantasyformationvalidity.formation_id)
FROM fantasyworld_fantasyformationvalidity
LEFT JOIN realworld_round AS _rr
ON _rr.id = round_id
LEFT JOIN fantasyworld_fantasyformation AS _ff
ON _ff.id = formation_id
WHERE is_valid = TRUE
AND _ff.coach_id = fc.id
-- use the value obtained from values:
AND _rr.sequence <= values.value
)
LEFT JOIN fantasyworld_FantasyFormationPlayer AS ffp
ON ffp.formation_id = ff.id
LEFT JOIN dbcache_fantasyplayercache AS fpc
ON ffp.player_id = fpc.fantasyplayer_id
-- use the value obtained from values again:
AND fpc.round_sequence = values.value
LEFT JOIN fantasyworld_fantasyformationvalidity AS ffv
ON ffv.formation_id = ff.id
) x
GROUP BY fantasycoach_id
Note in particular the CROSS JOIN which forms the cross product of two tables; this is the same thing as an INNER JOIN without any join predicate, and it can be written that way if desired.
The overall query could be at least a bit simplified, but I do not do so because it is a working example rather than an actual production query, so it is unclear what other changes would translate to the actual application.
In the example I create two tables. See how outer table have an alias you use in the inner select?
SQL Fiddle Demo
SELECT T.[value], (SELECT [property] FROM Table2 P WHERE P.[value] = T.[value])
FROM Table1 T
This is a better way for performance
SELECT T.[value], P.[property]
FROM Table1 T
INNER JOIN Table2 p
on P.[value] = T.[value];
Table 2 can be a QUERY instead of a real table
Third Option
Using a cte to calculate your values and then join back to the main table. This way you have the subquery logic separated from your final query.
WITH cte AS (
SELECT
T.[value],
T.[value] * T.[value] as property
FROM Table1 T
)
SELECT T.[value], C.[property]
FROM Table1 T
INNER JOIN cte C
on T.[value] = C.[value];
It might be helpful to extract the computation to a function that is called in the SELECT clause and is executed for each row of the result set
Here's the documentation for CREATE FUNCTION for SQL Server. It's probably similar to whatever database system you're using, and if not you can easily Google for it.
Here's an example of creating a function and using it in a query:
CREATE FUNCTION DoComputation(#parameter1 int)
RETURNS int
AS
BEGIN
-- Do some calculations here and return the function result.
-- This example returns the value of #parameter1 squared.
-- You can add additional parameters to the function definition if needed
DECLARE #Result int
SET #Result = #parameter1 * #parameter1
RETURN #Result
END
Here is an example of using the example function above in a query.
SELECT v.value, DoComputation(v.value) as ComputedValue
FROM [Values] v
ORDER BY value
I have two statements that I want to merge into one output.
Statement One:
select name from auxiliary_variable_inquiry
where inquiry_idbr_code = '063'
Returns the following list of names:
Name
------------
Affiliates
NetBookValue
Parents
Worldbase
Statement Two:
select name, value from auxiliary_variable_value
where inquiry_idbr_code = '063'
and ru_ref = 20120000008
and period = 200912
Returns the following:
Name Value
-------------------
Affiliates 112
NetBookValue 225.700
I would like to have an output like this:
Name Value
-------------------
Affiliates 112
NetBookValue 225.700
Parents 0
Worldbase 0
So basically, if the second query only returns 2 names and values, I'd still like to display the complete set of names from the first query, with no values. If all four values were returned by both queries, then all four would be displayed.
Sorry I must add, im using Ingres SQL so im unable to use the ISNULL function.
You can do a left join. This ensures that all records from the first table will stay included. Where value is null, no child record was found, and we use coalesce to display 0 in these cases.
select i.name, COALESCE(v.Value,0) from auxiliary_variable_inquiry i
left join auxiliary_variable_value v
on v.inquiry_idbr_code = i.inquiry_idbr_code
and v.ru_ref = 20120000008
and v.period = 200912
where i.inquiry_idbr_code = '063'
I'd recommend a self-JOIN using the LEFT OUTER JOIN syntax. Include your 'extra' conditions from the second query in the JOIN condition, while the first conditions stay in the WHERE, like this:
select a.name, CASE WHEN b.Value IS NULL THEN 0 ELSE b.Value END AS Value
from
auxiliary_variable_inquiry a
LEFT JOIN
auxiliary_variable_inquiry b ON
a.name = b.name and -- replace this with your real ID-based JOIN
a.inquiry_idbr_code = b.inquiry_idbr_code AND
b.ru_ref = 20120000008 AND
b.period = 200912
where a.inquiry_idbr_code = '063'
if i got right, you should use something like:
SELECT i.NAME,
v.NAME,
v.value
FROM auxiliary_variable_inquiry i
LEFT JOIN auxiliary_variable_value v
ON i.inquiry_idbr_code = v.inquiry_idbr_code
WHERE v.ru_ref = 20120000008
AND v.period = 200912
Im attempting to get some records from a table based on certain factors.
One of the factors is simply with fields on the same table, the other is when joining to another table, I want to compare the number of records in the joined table to a field on the first table. Below is a sample code.
select * from tDestinations D
left join tLiveCalls LC on LC.DestinationID = D.ID
where D.ConfigurationID = 1486
AND (D.Active = 1 AND D.AlternateFail > GETDATE())
-- Having COUNT(LC.ID) = D.Lines
Now from the code above I cant have the Count function in the where clause, and I cant have a field in in the having clause without it being in a function.
Im probably missing something very simple here. But I cant figure it out.
Any help is appreciated it.
EDIT: I do apologise should have explained the structure of the tables, the Destinations are single records, which the LiveCalls table can hold multiple records based on the Destinations ID (foreign key).
Thank you very much for everyones help. My final code:
select D.ID, D.Description, D.Lines, D.Active, D.AlternateFail, D.ConfigurationID, COUNT(LC.ID) AS LiveCalls from tDestinations D
left join tLiveCalls LC on LC.DestinationID = D.ID
where D.ConfigurationID = #ConfigurationID
AND (D.Active = 1 AND D.AlternateFail > GETDATE())
GROUP BY D.ID, D.Description, D.Lines, D.Active, D.AlternateFail, D.ConfigurationID
HAVING COUNT(LC.ID) <= D.Lines
The simple thing you're missing is the GROUP BY statement.
As JNK mentioned in the comments below, you cannot use an aggregate function (such as COUNT, AVG, SUM, MIN) if you don't have a GROUP BY clause, unless your SELECT statement only references literal values (and no column names).
Your code should probably be something like:
SELECT <someFields>
FROM tDestinations D
LEFT JOIN tLiveCalls LC on LC.DestinationID = D.ID
WHERE D.ConfigurationID = 1486
AND (D.Active = 1 AND D.AlternateFail > GETDATE())
GROUP BY <someFields>
HAVING COUNT(LC.ID) = D.Lines
Note that you have to specify the selected fields explicitely, in both the SELECT and GROUP BY statements (no * allowed).
you can only use having with aggregations. Actually having is the "where clause" for aggregation, BUT you can still have a where on the columns that you are no aggregating.
For example:
SELECT TABLE_TYPE, COUNT(*)
FROM INFORMATION_SCHEMA.TABLES
where TABLE_TYPE='VIEW'
group by TABLE_TYPE
having COUNT(*)>1
In your case you need to use havving count(*)=1
so, I think your query would be something like this:
select YOUR_COLUMN
from tDestinations D
left join tLiveCalls LC on LC.DestinationID = D.ID
where D.ConfigurationID = 1486 AND (D.Active = 1 AND D.AlternateFail > GETDATE())
group by YOUR_COLUMN
Having COUNT(LC.ID) = value
I'm trying to make a query to retrieve the region which got the most sales for sweet products. 'grupo_produto' is the product type, and 'regiao' is the region. So I got this query:
SELECT TOP 1 r.nm_regiao, (SELECT COUNT(*)
FROM Dw_Empresa
WHERE grupo_produto='1' AND
cod_regiao = d.cod_regiao) as total
FROM Dw_Empresa d
INNER JOIN tb_regiao r ON r.cod_regiao = d.cod_regiao ORDER BY total DESC
Then when i run the query, MS-Access asks for the "total" parameter. Why it doesn't consider the newly created 'column' I made in the select clause?
Thanks in advance!
Old Question I know, but it may help someone knowing than while you cant order by aliases, you can order by column index. For example, this will work without error :
SELECT
firstColumn,
IIF(secondColumn = '', thirdColumn, secondColumn) As yourAlias
FROM
yourTable
ORDER BY
2 ASC
The results would then be ordered by the values found in the second column wich is the Alias "yourAlias".
Aliases are only usable in the query output. You can't use them in other parts of the query. Unfortunately, you'll have to copy and paste the entire subquery to make it work.
You can do it like this
select * from(
select a + b as c, * from table)
order by c
Access has some differences compared to Sql Server.
Why it doesn't consider the newly
created 'column' I made in the select
clause?
Because Access (ACE/Jet) is not compliant with the SQL-92 Standard.
Consider this example, which is valid SQL-92:
SELECT a AS x, c - b AS y
FROM MyTable
ORDER
BY x, y;
In fact, x and y the only valid elements in the ORDER BY clause because all others are out of scope (ordinal numbers of columns in the SELECT clause are valid though their use id deprecated).
However, Access chokes on the above syntax. The equivalent Access syntax is this:
SELECT a AS x, c - b AS y
FROM MyTable
ORDER
BY a, c - b;
However, I understand from #Remou's comments that a subquery in the ORDER BY clause is invalid in Access.
Try using a subquery and order the results in an outer query.
SELECT TOP 1 * FROM
(
SELECT
r.nm_regiao,
(SELECT COUNT(*)
FROM Dw_Empresa
WHERE grupo_produto='1' AND cod_regiao = d.cod_regiao) as total
FROM Dw_Empresa d
INNER JOIN tb_regiao r ON r.cod_regiao = d.cod_regiao
) T1
ORDER BY total DESC
(Not tested.)
How about:
SELECT TOP 1 r.nm_regiao
FROM (SELECT Dw_Empresa.cod_regiao,
Count(Dw_Empresa.cod_regiao) AS CountOfcod_regiao
FROM Dw_Empresa
WHERE Dw_Empresa.[grupo_produto]='1'
GROUP BY Dw_Empresa.cod_regiao
ORDER BY Count(Dw_Empresa.cod_regiao) DESC) d
INNER JOIN tb_regiao AS r
ON d.cod_regiao = r.cod_regiao
I suggest using an intermediate query.
SELECT r.nm_regiao, d.grupo_produto, COUNT(*) AS total
FROM Dw_Empresa d INNER JOIN tb_regiao r ON r.cod_regiao = d.cod_regiao
GROUP BY r.nm_regiao, d.grupo_produto;
If you call that GroupTotalsByRegion, you can then do:
SELECT TOP 1 nm_regiao, total FROM GroupTotalsByRegion
WHERE grupo_produto = '1' ORDER BY total DESC
You may think it's extra work to create the intermediate query (and, in a sense, it is), but you will also find that many of your other queries will be based off of GroupTotalsByRegion. You want to avoid repeating that logic in many other queries. By keeping it in one view, you provide a simplified route to answering many other questions.
How about use:
WITH xx AS
(
SELECT TOP 1 r.nm_regiao, (SELECT COUNT(*)
FROM Dw_Empresa
WHERE grupo_produto='1' AND
cod_regiao = d.cod_regiao) as total
FROM Dw_Empresa d
INNER JOIN tb_regiao r ON r.cod_regiao = d.cod_regiao
) SELECT * FROM xx ORDER BY total