I'm having this Mysql query, It works:
SELECT
nom
,prenom
,(SELECT GROUP_CONCAT(category_en) FROM
(SELECT DISTINCT category_en FROM categories c WHERE id IN
(SELECT DISTINCT category_id FROM m3allems_to_categories m2c WHERE m3allem_id = 37)
) cS
) categories
,(SELECT GROUP_CONCAT(area_en) FROM
(SELECT DISTINCT area_en FROM areas c WHERE id IN
(SELECT DISTINCT area_id FROM m3allems_to_areas m2a WHERE m3allem_id = 37)
) aSq
) areas
FROM m3allems m
WHERE m.id = 37
The result is:
nom prenom categories areas
Man Multi Carpentry,Paint,Walls Beirut,Baalbak,Saida
It works correclty, but only when i hardcode into the query the id that I want (37).
I want it to work for all entries in the m3allem table, so I try this:
SELECT
nom
,prenom
,(SELECT GROUP_CONCAT(category_en) FROM
(SELECT DISTINCT category_en FROM categories c WHERE id IN
(SELECT DISTINCT category_id FROM m3allems_to_categories m2c WHERE m3allem_id = m.id)
) cS
) categories
,(SELECT GROUP_CONCAT(area_en) FROM
(SELECT DISTINCT area_en FROM areas c WHERE id IN
(SELECT DISTINCT area_id FROM m3allems_to_areas m2a WHERE m3allem_id = m.id)
) aSq
) areas
FROM m3allems m
And I get an error:
Unknown column 'm.id' in 'where
clause'
Why?
From the MySql manual:
13.2.8.7. Correlated Subqueries
[...]
Scoping rule: MySQL evaluates from inside to outside.
So... do this not work when the subquery is in a SELECT section? I did not read anything about that.
Does anyone know? What should I do? It took me a long time to build this query... I know it's a monster query but it gets what I want in a single query, and I am so close to getting it to work!
Can anyone help?
You can only correlate one level deep.
Use:
SELECT m.nom,
m.prenom,
x.categories,
y.areas
FROM m3allens m
LEFT JOIN (SELECT m2c.m3allem_id,
GROUP_CONCAT(DISTINCT c.category_en) AS categories
FROM CATEGORIES c
JOIN m3allems_to_categories m2c ON m2c.category_id = c.id
GROUP BY m2c.m3allem_id) x ON x.m3allem_id = m.id
LEFT JOIN (SELECT m2a.m3allem_id,
GROUP_CONCAT(DISTINCT a.area_en) AS areas
FROM AREAS a
JOIN m3allems_to_areas m2a ON m2a.area_id = a.id
GROUP BY m2a.m3allem_id) y ON y.m3allem_id = m.id
WHERE m.id = ?
The reason for the error is that in the subquery m is not defined. It is defined later in the outer query.
Related
Is there a way to rewrite my query into a join one.
The question I have to solve is: List the names of green items sold by no department on the first floor. Do not show duplicates.
select distinct itemname from xsale where deptname in (
select deptname from xdept where deptfloor <> 1
)
intersect (
select itemname from xitem where itemcolor= 'green'
)
I have been stuck at this exercise a couple of days now because the join statements don't make much sense to me even after reading about it. I hope someone can help me.
I think the following query will help you about how to use join statment for your query;
EDITED
select distinct xs.itemname from xsale xs
inner join xdept xp on xs.deptname=xp.deptname
where xp.deptfloor <>1
intersect
(select xi.itemname from xitem xi where xi.itemcolor= 'green')
Check if this works for you
Select Distinct a.itemname from xsale a
INNER JOIN xdept b on a.deptName = b.deptName
INNER JOIN xitem c on a.itemName = c.itemname
Where b.deptfloor <> 1 and c.itemcolor = 'green'
I think you can express the logic as an EXIST and NOT EXIST query:
SELECT itemname
FROM xitem
WHERE itemcolor = 'green' -- all green items
AND EXISTS (
-- exists a sale for that item
SELECT 1
FROM xsale
WHERE xsale.itemname = xitem.itemname
AND NOT EXISTS (
-- not exists a department in those sales with floor = 1
SELECT 1
FROM xdept
WHERE xdept.deptname = xsale.deptname AND xdept.deptfloor = 1
)
)
It is often best to build your queries up step by step. So if we break the problem down:
List the names of green items sold
SELECT i.ItemName
FROM xitem AS i
WHERE i.ItemColor = 'Green';
Items sold by a department on the first floor
SELECT s.ItemName
FROM xsale AS s
INNER JOIN xdept AS d
ON d.DeptName = s.DeptName
WHERE d.DeptFloor = 1;
So now, you want all the items output by the first query, except for those that appear in the 2nd:
SELECT i.ItemName
FROM xitem AS i
WHERE i.ItemColor = 'Green'
EXCEPT
SELECT s.ItemName
FROM xsale AS s
INNER JOIN xdept AS d
ON d.DeptName = s.DeptName
WHERE d.DeptFloor = 1;
Then the final part:
Do not show duplicates:
SELECT DISTINCT i.ItemName
FROM xitem AS i
WHERE i.ItemColor = 'Green'
EXCEPT
SELECT s.ItemName
FROM xsale AS s
INNER JOIN xdept AS d
ON d.DeptName = s.DeptName
WHERE d.DeptFloor = 1;
An alertanative to EXCEPT would be NOT EXISTS, they will almost always result in the same execution plan, but I find NOT EXISTS is more flexible (you don't need the same columns in both queries):
SELECT i.ItemName
FROM xitem AS i
WHERE i.ItemColor = 'Green'
AND NOT EXISTS
( SELECT 1
FROM xsale AS s
INNER JOIN xdept AS d
ON d.DeptName = s.DeptName
WHERE d.DeptFloor = 1
AND s.ItemName = i.ItemName
)
GROUP BY i.ItemName;
Again to show an alternative, I have used GROUP BY rather than DISTINCT. In most cases these are semantically equivalent, but there are scenarios where GROUP BY will perform better (namely when a scalar function is involved - GROUP BY will remove duplciates first, and then execute the funciton on all remaining values, DISTINCT will execute the function first and remove duplicate results).
Examples on DB Fiddle
I have been creating sql query as shown below :
select * from (select DISTINCT * from (select po.tGroup_id,pp.tGroup_id as GroupID from tPhos_Line_Operator PO
LEFT join tPhos_Line_Parameter PP
on PO.tGroup_id = PP.tGroup_id) A) Ac
left JOIN
(SELECT top 1 tGroup_id FROM tGROUP_LOG order by id desc) B
on Ac.tGroup_id = B.tGroup_id
I was expecting to see records like in the image below :
But I keep getting this records :
I tried to hardcode in the left join by putting the tGroup_id=29 and it work as I got the exact record I want. Refer to first image.
select * from (select DISTINCT * from (select po.tGroup_id,pp.tGroup_id as GroupID from tPhos_Line_Operator PO
LEFT join tPhos_Line_Parameter PP
on PO.tGroup_id = PP.tGroup_id) A) Ac
left JOIN
(SELECT top 1 tGroup_id FROM tGROUP_LOG where tGroup_id = 29 order by id desc
) B
on Ac.tGroup_id = B.tGroup_id
I do not want to hardcode it.
Can someone tell me where did I missed out or did wrong?
Thanks in advance.
I have found a way, instead of using top 1, I can use max.
SELECT max(id) as TESTID,tGroup_id FROM tGROUP_LOG
group by tGroup_id
I consider this has fixed my issue. Thanks
I am new to PostgreSQL and I have a problem with the following query:
WITH relevant_einsatz AS (
SELECT einsatz.fahrzeug,einsatz.mannschaft
FROM einsatz
INNER JOIN bergefahrzeug ON einsatz.fahrzeug = bergefahrzeug.id
),
relevant_mannschaften AS (
SELECT DISTINCT relevant_einsatz.mannschaft
FROM relevant_einsatz
WHERE relevant_einsatz.fahrzeug IN (SELECT id FROM bergefahrzeug)
)
SELECT mannschaft.id,mannschaft.rufname,person.id,person.nachname
FROM mannschaft,person,relevant_mannschaften WHERE mannschaft.leiter = person.id AND relevant_mannschaften.mannschaft=mannschaft.id;
This query is working basically - but in "relevant_mannschaften" I am currently selecting each mannschaft, which has been to an relevant_einsatz with at least 1 bergefahrzeug.
Instead of this, I want to select into "relevant_mannschaften" each mannschaft, which has been to an relevant_einsatz WITH EACH from bergefahrzeug.
Does anybody know how to formulate this change?
The information you provide is rather rudimentary. But tuning into my mentalist skills, going out on a limb, I would guess this untangled version of the query does the job much faster:
SELECT m.id, m.rufname, p.id, p.nachname
FROM person p
JOIN mannschaft m ON m.leiter = p.id
JOIN (
SELECT e.mannschaft
FROM einsatz e
JOIN bergefahrzeug b ON b.id = e.fahrzeug -- may be redundant
GROUP BY e.mannschaft
HAVING count(DISTINCT e.fahrzeug)
= (SELECT count(*) FROM bergefahrzeug)
) e ON e.mannschaft = m.id
Explain:
In the subquery e I count how many DISTINCT mountain-vehicles (bergfahrzeug) have been used by a team (mannschaft) in all their deployments (einsatz): count(DISTINCT e.fahrzeug)
If that number matches the count in table bergfahrzeug: (SELECT count(*) FROM bergefahrzeug) - the team qualifies according to your description.
The rest of the query just fetches details from matching rows in mannschaft and person.
You don't need this line at all, if there are no other vehicles in play than bergfahrzeuge:
JOIN bergefahrzeug b ON b.id = e.fahrzeug
Basically, this is a special application of relational division. A lot more on the topic under this related question:
How to filter SQL results in a has-many-through relation
Do not know how to explain it, but here is an example how I solved this problem, just in case somebody has the some question one day.
WITH dfz AS (
SELECT DISTINCT fahrzeug,mannschaft FROM einsatz WHERE einsatz.fahrzeug IN (SELECT id FROM bergefahrzeug)
), abc AS (
SELECT DISTINCT mannschaft FROM dfz
), einsatzmannschaften AS (
SELECT abc.mannschaft FROM abc WHERE (SELECT sum(dfz.fahrzeug) FROM dfz WHERE dfz.mannschaft = abc.mannschaft) = (SELECT sum(bergefahrzeug.id) FROM bergefahrzeug)
)
SELECT mannschaft.id,mannschaft.rufname,person.id,person.nachname
FROM mannschaft,person,einsatzmannschaften WHERE mannschaft.leiter = person.id AND einsatzmannschaften.mannschaft=mannschaft.id;
I have the following query:
SELECT sum((select count(*) as itemCount) * "SalesOrderItems"."price") as amount, 'rma' as
"creditType", "Clients"."company" as "client", "Clients".id as "ClientId", "Rmas".*
FROM "Rmas" JOIN "EsnsRmas" on("EsnsRmas"."RmaId" = "Rmas"."id")
JOIN "Esns" on ("Esns".id = "EsnsRmas"."EsnId")
JOIN "EsnsSalesOrderItems" on("EsnsSalesOrderItems"."EsnId" = "Esns"."id" )
JOIN "SalesOrderItems" on("SalesOrderItems"."id" = "EsnsSalesOrderItems"."SalesOrderItemId")
JOIN "Clients" on("Clients"."id" = "Rmas"."ClientId" )
WHERE "Rmas"."credited"=false AND "Rmas"."verifyStatus" IS NOT null
GROUP BY "Clients".id, "Rmas".id;
The problem is that the table "EsnsSalesOrderItems" can have the same EsnId in different entries. I want to restrict the query to only pull the last entry in "EsnsSalesOrderItems" that has the same "EsnId".
By "last" entry I mean the following:
The one that appears last in the table "EsnsSalesOrderItems". So for example if "EsnsSalesOrderItems" has two entries with "EsnId" = 6 and "createdAt" = '2012-06-19' and '2012-07-19' respectively it should only give me the entry from '2012-07-19'.
SELECT (count(*) * sum(s."price")) AS amount
, 'rma' AS "creditType"
, c."company" AS "client"
, c.id AS "ClientId"
, r.*
FROM "Rmas" r
JOIN "EsnsRmas" er ON er."RmaId" = r."id"
JOIN "Esns" e ON e.id = er."EsnId"
JOIN (
SELECT DISTINCT ON ("EsnId") *
FROM "EsnsSalesOrderItems"
ORDER BY "EsnId", "createdAt" DESC
) es ON es."EsnId" = e."id"
JOIN "SalesOrderItems" s ON s."id" = es."SalesOrderItemId"
JOIN "Clients" c ON c."id" = r."ClientId"
WHERE r."credited" = FALSE
AND r."verifyStatus" IS NOT NULL
GROUP BY c.id, r.id;
Your query in the question has an illegal aggregate over another aggregate:
sum((select count(*) as itemCount) * "SalesOrderItems"."price") as amount
Simplified and converted to legal syntax:
(count(*) * sum(s."price")) AS amount
But do you really want to multiply with the count per group?
I retrieve the the single row per group in "EsnsSalesOrderItems" with DISTINCT ON. Detailed explanation:
Select first row in each GROUP BY group?
I also added table aliases and formatting to make the query easier to parse for human eyes. If you could avoid camel case you could get rid of all the double quotes clouding the view.
Something like:
join (
select "EsnId",
row_number() over (partition by "EsnId" order by "createdAt" desc) as rn
from "EsnsSalesOrderItems"
) t ON t."EsnId" = "Esns"."id" and rn = 1
this will select the latest "EsnId" from "EsnsSalesOrderItems" based on the column creation_date. As you didn't post the structure of your tables, I had to "invent" a column name. You can use any column that allows you to define an order on the rows that suits you.
But remember the concept of the "last row" is only valid if you specifiy an order or the rows. A table as such is not ordered, nor is the result of a query unless you specify an order by
Necromancing because the answers are outdated.
Take advantage of the LATERAL keyword introduced in PG 9.3
left | right | inner JOIN LATERAL
I'll explain with an example:
Assuming you have a table "Contacts".
Now contacts have organisational units.
They can have one OU at a point in time, but N OUs at N points in time.
Now, if you have to query contacts and OU in a time period (not a reporting date, but a date range), you could N-fold increase the record count if you just did a left join.
So, to display the OU, you need to just join the first OU for each contact (where what shall be first is an arbitrary criterion - when taking the last value, for example, that is just another way of saying the first value when sorted by descending date order).
In SQL-server, you would use cross-apply (or rather OUTER APPLY since we need a left join), which will invoke a table-valued function on each row it has to join.
SELECT * FROM T_Contacts
--LEFT JOIN T_MAP_Contacts_Ref_OrganisationalUnit ON MAP_CTCOU_CT_UID = T_Contacts.CT_UID AND MAP_CTCOU_SoftDeleteStatus = 1
--WHERE T_MAP_Contacts_Ref_OrganisationalUnit.MAP_CTCOU_UID IS NULL -- 989
-- CROSS APPLY -- = INNER JOIN
OUTER APPLY -- = LEFT JOIN
(
SELECT TOP 1
--MAP_CTCOU_UID
MAP_CTCOU_CT_UID
,MAP_CTCOU_COU_UID
,MAP_CTCOU_DateFrom
,MAP_CTCOU_DateTo
FROM T_MAP_Contacts_Ref_OrganisationalUnit
WHERE MAP_CTCOU_SoftDeleteStatus = 1
AND MAP_CTCOU_CT_UID = T_Contacts.CT_UID
/*
AND
(
(#in_DateFrom <= T_MAP_Contacts_Ref_OrganisationalUnit.MAP_KTKOE_DateTo)
AND
(#in_DateTo >= T_MAP_Contacts_Ref_OrganisationalUnit.MAP_KTKOE_DateFrom)
)
*/
ORDER BY MAP_CTCOU_DateFrom
) AS FirstOE
In PostgreSQL, starting from version 9.3, you can do that, too - just use the LATERAL keyword to achieve the same:
SELECT * FROM T_Contacts
--LEFT JOIN T_MAP_Contacts_Ref_OrganisationalUnit ON MAP_CTCOU_CT_UID = T_Contacts.CT_UID AND MAP_CTCOU_SoftDeleteStatus = 1
--WHERE T_MAP_Contacts_Ref_OrganisationalUnit.MAP_CTCOU_UID IS NULL -- 989
LEFT JOIN LATERAL
(
SELECT
--MAP_CTCOU_UID
MAP_CTCOU_CT_UID
,MAP_CTCOU_COU_UID
,MAP_CTCOU_DateFrom
,MAP_CTCOU_DateTo
FROM T_MAP_Contacts_Ref_OrganisationalUnit
WHERE MAP_CTCOU_SoftDeleteStatus = 1
AND MAP_CTCOU_CT_UID = T_Contacts.CT_UID
/*
AND
(
(__in_DateFrom <= T_MAP_Contacts_Ref_OrganisationalUnit.MAP_KTKOE_DateTo)
AND
(__in_DateTo >= T_MAP_Contacts_Ref_OrganisationalUnit.MAP_KTKOE_DateFrom)
)
*/
ORDER BY MAP_CTCOU_DateFrom
LIMIT 1
) AS FirstOE
Try using a subquery in your ON clause. An abstract example:
SELECT
*
FROM table1
JOIN table2 ON table2.id = (
SELECT id FROM table2 WHERE table2.table1_id = table1.id LIMIT 1
)
WHERE
...
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