I have the following sql command:
SELECT "USERNAME"."TOPICS".VALUE,
"USERNAME"."TOPICS".QID,
"USERNAME"."QUESTION".QRATING
FROM "USERNAME"."TOPICS" JOIN "USERNAME"."QUESTION"
ON "USERNAME"."TOPICS".QID = "USERNAME"."QUESTION".QID
AND "USERNAME"."TOPICS".VALUE = 'kia'
ORDER BY QRATING DESC
It works really well, but I want to count how many element returns. So I tried to use:
SELECT COUNT("USERNAME"."TOPICS".QID)
FROM "USERNAME"."TOPICS" JOIN "USERNAME"."QUESTION"
ON "USERNAME"."TOPICS".QID = "USERNAME"."QUESTION".QID
AND "USERNAME"."TOPICS".VALUE = 'kia'
ORDER BY QRATING DESC
But I get the error :
Column reference 'USERNAME.TOPICS.VALUE' is invalid. When the SELECT
list contains at least one aggregate then all entries must be valid
aggregate expressions.
What is the problem?
Hmmm. The ORDER BY should be getting the error, not the SELECT. However, your query would be much easier to understand using table aliases:
SELECT COUNT(t.QID)
FROM "USERNAME"."TOPICS" t JOIN
"USERNAME"."QUESTION" q
ON t.QID = q.QID AND t.VALUE = 'kia';
If the first query works, I see no reason why this would not (and your original without the ORDER BY should also work).
Related
I'm trying to execute a query inside LabVIEW so I can informations stored in a Oracle Database, but when a try to execute a query with parenthesis it doesn't works and gives me this erro:
ADO Error: 0x80004005 Exception occured in Microsoft OLE DB Provider for ODBC Drivers: [Oracle][ODBC][Ora]ORA-00907: parêntese direito não encontrado
Here is the SQL query I'm trying to execute:
SELECT
F.CODIGOFAIXAMODELO,
F.CODIGOMODELO,
F.INICIOESCALA,
F.FUNDOESCALA,
F.FAIXA,
F.DESCFAIXA,
F.ORDEM,
P.CODIGOPROCEDIMENTO
FROM FAIXAS F INNER JOIN PROCEDS P ON F.CODIGOFAIXAMODELO=(
SELECT
CODIGOFAIXAMODELO
FROM PROCEDS
WHERE
PROCEDS.CODIGOFAIXAMODELO=F.CODIGOFAIXAMODELO
LIMIT 1
)
WHERE
F.CODIGOMODELO='%CODIGOMODELO%'
ORDER BY F.ORDEM ASC;
The %CODIGOMODELO% is replaced with a value by LabVIEW.
When I try the following Query it works:
SELECT
F.CODIGOFAIXAMODELO,
F.CODIGOMODELO,
F.INICIOESCALA,
F.FUNDOESCALA,
F.FAIXA,
F.DESCFAIXA,
F.ORDEM,
P.CODIGOPROCEDIMENTO
FROM FAIXAS F INNER JOIN PROCEDS P ON F.CODIGOFAIXAMODELO=P.CODIGOFAIXAMODELO
WHERE
F.CODIGOMODELO='%CODIGOMODELO%'
ORDER BY F.ORDEM ASC;
The problem with the second solution is that it returns me many P.CODIGOPROCEDIMENTO, and what I want is to get only one even when there are many.
there is no LIMIT function in Oracle
you need to use ROWNUM = 1 or OFFSET 0 ROWS FETCH NEXT 1 ROWS ONLY
Also as it is stated by #APC, you shouldn't be joining your table on a subquery.
I would write it this way. It may be more efficient and more readable to avoid trying to evaluate a subquery inside an expression:
SELECT
F.CODIGOFAIXAMODELO,
F.CODIGOMODELO,
F.INICIOESCALA,
F.FUNDOESCALA,
F.FAIXA,
F.DESCFAIXA,
F.ORDEM,
P.CODIGOPROCEDIMENTO
FROM FAIXAS F
INNER JOIN (
SELECT
P1.CODIGOFAIXAMODELO,
MAX(P1.CODIGOPROCEDIMENTO) AS CODIGOPROCEDIMENTO
FROM PROCEDS P1
GROUP BY P1.CODIGOFAIXAMODELO
) P ON P.CODIGOFAIXAMODELO = F.CODIGOFAIXAMODELO
WHERE F.CODIGOMODELO = '%CODIGOMODELO%'
ORDER BY F.ORDEM ASC;
MAX() is an Aggregate Function that will return only one value for each group - specified in the GROUP BY clause. Therefore, using a subquery and joining on CODIGOFAIXAMODELO ensures that only one row is filtered against the main query.
The results really depend on the key structures, datatypes and how many rows are available in PROCEDS. There are of course other, more complex methods to achieve the same result, such as using Analytic Functions.
I think you can write it this way:
SELECT
F.CODIGOFAIXAMODELO,
F.CODIGOMODELO,
F.INICIOESCALA,
F.FUNDOESCALA,
F.FAIXA,
F.DESCFAIXA,
F.ORDEM,
P.CODIGOPROCEDIMENTO
FROM FAIXAS F INNER JOIN PROCEDS P ON F.CODIGOFAIXAMODELO=P.CODIGOFAIXAMODELO and ROWNUM = 1
WHERE
F.CODIGOMODELO='%CODIGOMODELO%'
ORDER BY F.ORDEM ASC;
I have a problem to join thoses 4 tables
Model of my database
I want to count the number of reservations with different sorts (user [mrbs_users.id], room [mrbs_room.room_id], area [mrbs_area.area_id]).
Howewer when I execute this query (for the user (id=1) )
SELECT count(*)
FROM mrbs_users JOIN mrbs_entry ON mrbs_users.name=mrbs_entry.create_by
JOIN mrbs_room ON mrbs_entry.room_id = mrbs_room.id
JOIN mrbs_area ON mrbs_room.area_id = mrbs_area.id
WHERE mrbs_entry.start_time BETWEEN "145811700" and "1463985000"
or
mrbs_entry.end_time BETWEEN "1458120600" and "1463992200" and mrbs_users.id = 1
The result is the total number of reservations of every user, not just the user who has the id = 1.
So if anyone could help me.. Thanks in advance.
Use parentheses in the where clause whenever you have more than one condition. Your where is parsed as:
WHERE (mrbs_entry.start_time BETWEEN "145811700" and "1463985000" ) or
(mrbs_entry.end_time BETWEEN "1458120600" and "1463992200" and
mrbs_users.id = 1
)
Presumably, you intend:
WHERE (mrbs_entry.start_time BETWEEN 145811700 and 1463985000 or
mrbs_entry.end_time BETWEEN 1458120600 and 1463992200
) and
mrbs_users.id = 1
Also, I removed the quotes around the string constants. It is bad practice to mix data types, and in some databases, the conversion between types can make the query less efficient.
The problem you've faced caused by the incorrect condition WHERE.
So, should be:
WHERE (mrbs_entry.start_time BETWEEN 145811700 AND 1463985000 )
OR
(mrbs_entry.end_time BETWEEN 1458120600 AND 1463992200 AND mrbs_users.id = 1)
Moreover, when you use only INNER JOIN (JOIN) then it be better to avoid WHERE clause, because the ON clause is executed before the WHERE clause, so criteria there would perform faster.
Your query in this case should be like this:
SELECT COUNT(*)
FROM mrbs_users
JOIN mrbs_entry ON mrbs_users.name=mrbs_entry.create_by
JOIN mrbs_room ON mrbs_entry.room_id = mrbs_room.id
AND
(mrbs_entry.start_time BETWEEN 145811700 AND 1463985000
OR ( mrbs_entry.end_time BETWEEN 1458120600 AND 1463992200 AND mrbs_users.id = 1)
)
JOIN mrbs_area ON mrbs_room.area_id = mrbs_area.id
I have tried endless things to get this to work and it seems to break over and over again and not work. I'm trying to GROUP BY product after I have calculated the field quantity returned/quantity ordered, but I get the error
your query does not include the specified expression 'quantity_returned/quantity_ordered' as part of an aggregate function.
I do not want to GROUP BY quantity_returned, quantity_ordered, and product, I only want to GROUP BY product.
Here's what my SQL looks like currently...
SELECT
quantity_returned/quantity_ordered AS percentage_returned,
quantity_returned,
quantity_ordered,
returns_fact.product
FROM
Customer_dimension
INNER JOIN
(
Product_dimension
INNER JOIN
(
Day_dimension
INNER JOIN
returns_fact
ON Day_dimension.day_key = returns_fact.day_key
)
ON Product_dimension.product_key = returns_fact.product_key
)
ON Customer_dimension.customer_key = returns_fact.customer_key
GROUP BY returns_fact.product;
When you use a group by you need to actually include everything in your select that isn't a aggregate function.
I have no idea how your tables are set up, but I am throwing a blind dart. If you provide fields in each of the 4 tables someone will be better able to help.
SELECT returns_fact.product, count(quantity_returned), count(quantity_ordered), count(quantity_returned)/count(quantity_ordered) as percentage returned
As a newbie to Postgresql (I'm moving over because I'm moving my site to heroku who only support it, I'm having to refactor some of my queries and code. Here's a problem that I can't quite understand the problem with:
PGError: ERROR: column "l_user_id" does not exist
LINE 1: ...t_id where l.user_id = 8 order by l2.geopoint_id, l_user_id ...
^
...query:
select distinct
l2.*,
l.user_id as l_user_id,
l.geopoint_id as l_geopoint_id
from locations l
left join locations l2 on l.geopoint_id = l2.geopoint_id
where l.user_id = 8
order by l2.geopoint_id, l_user_id = l2.user_id desc
clause "l.user_id as l_user_id, l.geopoint_id as l_geopoint_id" was added because apparently postgres doesn't like order clauses with fields not selected. But the error I now get makes it look like I'm also not getting aliasing. Anybody with postgres experience see the problem?
I'm likely to have a bunch of these problems -- the queries worked fine in mySql...
In PostgreSQL you can not use expression with an alias in order by. Only plain aliases work there. Your query should look like this:
select distinct
l2.*,
l.user_id as l_user_id,
l.geopoint_id as l_geopoint_id
from locations l
left join locations l2 on l.geopoint_id = l2.geopoint_id
where l.user_id = 8
order by l2.geopoint_id, l.user_id = l2.user_id desc;
I assume you mean that l2.user_id=l.user_id ought to go first.
This is relevant message on PostgreSQL-general mailing list. The following is in the documentation of ORDER BY clause:
Each expression can be the name or
ordinal number of an output
column (SELECT list item), or it
can be an arbitrary expression formed
from input-column values.
So no aliases when expression used.
I ran into this same problem using functions from fuzzystrmatch - particularly the levenshtein function. I needed to both sort by the string distance, and filter results by the string distance. I was originally trying:
SELECT thing.*,
levenshtein(thing.name, '%s') AS dist
FROM thing
WHERE dist < character_length(thing.name)/2
ORDER BY dist
But, of course, I got the error "column"dist" does not exist" from the WHERE clause. I tried this and it worked:
SELECT thing.*,
(levenshtein(thing.name, '%s')) AS dist
FROM thing
ORDER BY dist
But I needed to have that qualification in the WHERE clause. Someone else in this question said that the WHERE clause is evaluated before ORDER BY, thus the column was non-existent when it evaluated the WHERE clause. Going by that advice, I figured out that a nested SELECT statement does the trick:
SELECT * FROM
(SELECT thing.*,
(levenshtein(thing.name, '%s')) AS dist
FROM thing
ORDER BY dist
) items
WHERE dist < (character_length(items.name)/2)
Note that the "items" table alias is required and the dist column alias is accessible in the outer SELECT because it's unique in the statement. It's a little bit funky and I'm surprised that it has to be this way in PG - but it doesn't seem to take a performance hit so I'm satisfied.
You have:
order by l2.geopoint_id, l_user_id = l2.user_id desc
in your query. That's illegal syntax. Remove the = l2.user_id part (move it to where if that's one of the join conditions) and it should work.
Update Below select (with = l2.user_id removed) should work just fine. I've tested it (with different table / column names, obviously) on Postgres 8.3
select distinct
l2.*,
l.user_id as l_user_id,
l.geopoint_id as l_geopoint_id
from locations l
left join locations l2 on l.geopoint_id = l2.geopoint_id
where l.user_id = 8
order by l2.geopoint_id, l_user_id desc
"was added because apparently postgres doesn't like order clauses with fields not selected"
"As far as order by goes - yes, PostgresQL (and many other databases) does not allow ordering by columns that are not listed in select clause."
Just plain untrue.
=> SELECT id FROM t1 ORDER BY owner LIMIT 5;
id
30
10
20
50
40
(5 rows)
LEFT JOIN PatientClinics AB ON PPhy.PatientID = AB.PatientID
JOIN Clinics CL ON CL.ID = AB.ClinicID
AND COUNT(AB.ClinicID) = 1
I get error using Count(AB.ClinicID) = 1 (ClinicID has duplicate values in the table and
I want to use only 1 value of each duplicate value of ClinicId to produce result)
What mistake am I making?
I've never seen a COUNT() being used in a JOIN before. Maybe you should use:
HAVING COUNT(AB.ClinicID) = 1
instead.
Count() can't be used as a join/filter predicate. It can be used in the HAVING clause however. You should include the entire query in order to get a better example of how to rewrite it.
maybe investigate the HAVING clause instead of using COUNT where you put it.
hard to help without the full query.