Hi I want to get the count of this linq query.Im using entity framework with repository pattern.
It is possible to get the result by queryUserWalls.ToList().Count()
which I think is inefficient.
Can any body help.
var queryUserWalls = (from participation in _eventParticipationRepository.GetAll()
join eve in _eventRepository.GetAll() on participation.EventId equals eve.Id
join userWall in _userWallRepository.GetAll() on participation.EventId equals userWall.EventId
where participation.UserId == userId
select userWall.Id)
.Union(from userWall in _userWallRepository.GetAll()
select userWall.Id);
Leave out the ToList because it forces query execution. You want to use Queryable.Count, not Enumerable.Count. Then, it will execute on the server.
Related
I am currently doing some SQL magic and wanted to update the stock in my companies ERP program. However if I try to run the following query I get the error mentioned in the title.
update llx_product lp
set stock = (select sum(ps.reel)
from llx_product_stock as ps, llx_entrepot as w
where w.entity IN (1)
and w.rowid = ps.fk_entrepot
and ps.fk_product = lp.rowid
group by ps.rowid)
The subquery by itself returns just one row if used with a rowid for the product.
select sum(ps.reel)
from llx_product_stock as ps, llx_entrepot as w
where w.entity in (1)
and w.rowid = ps.fk_entrepot
and ps.fk_product = 7372
group by ps.rowid
Any help would be appreciated
I would suggest writing the query as:
update llx_product lp
set stock = (select sum(ps.reel)
from llx_product_stock ps join
llx_entrepot w
on ps.fk_product = lp.rowid
where w.entity in (1) and
w.rowid = ps.fk_entrepot
);
An aggregation query with no group by cannot return more than one row. It is unclear how your version is returning more than one row because the key used in the group by also has an equality comparison. Perhaps there is some type conversion issue at play.
But in any case, without the group by, you cannot get the error you are currently getting.
For anyone wondering the solution to my issue was a very simple query, Gordon pointed in the right direction and I made it harder than it should be.
update llx_product lp
left join llx_product_stock ps on lp.rowid = ps.fk_product
set lp.stock = ps.reel
I am working on a query for a datatable and I can't seem to get it to display how I want, I don't know if this is even possible in SQL What I am looking to do is get a query to respond with ideally an extra column of Boolean type.
Currently I can run two queries and they both work perfectly but I can't work out how to join them together bellow is the code from my first query what this does is return beers a user has tried this works fine and as expected and returns as expected.
SELECT *
FROM keg.beer
JOIN keg.userbeer
ON beer.id = userbeer.beer_id
WHERE userbeer.username_id = 1;
The second query is even simpler and is just a select getting the list of beers.
SELECT * FROM keg.beer
What I want to do is run a query and have it return a list of beers with a Boolean value if the user has tried it or not.
You're not going to run into too many scenarios for "Desired Results" that can't be produced with plain 'ol SQL. In this case you'll use a CASE statement to determine if the person has tried a beer. You'll also want a LEFT OUTER JOIN so you don't drop records coming from your beer table when your filtered userid doesn't have a userbeer record for that beer:
SELECT
beer.name,
beer.id,
beer.country,
CASE WHEN userbeer.username_id IS NULL THEN 0 ELSE 1 END AS user_tried_beer_boolean
FROM keg.beer
LEFT OUTER JOIN keg.userbeer
ON beer.id = userbeer.beer_id
AND userbeer.username_id = 1;
As #SeanLange mentioned in the comments here, the restriction of the WHERE statement for the userid would cause records to be dropped that you want in your result set, so we move the restriction of username_id = 1 to the ON portion of the LEFT OUTER JOIN so that the userbeer table results are restricted to just that user before it's joined to the beer table.
Now I need a drink.
SELECT b.id,
b.name,
CASE WHEN u.username_id IS NOT NULL THEN TRUE ELSE FALSE END AS userdrankbeer
FROM keg.beer b
LEFT JOIN ( SELECT * FROM keg.userbeer WHERE username_id = 1 ) u
ON beer.id = userbeer.beer_id
;
I have made a query that looks like this
Query 1.
SELECT zlec_status.nazwa AS Status,
piorytet.nazwa AS Priorytet,
Concat(koord.imie, ' ', koord.nazwisko) AS `Koordynator`,
Concat(zlec_adresy.miasto, ' - ', zlec_adresy.ulica, ' ',
zlec_adresy.oddzial)
AS `adres`,
zlec_z_dnia,zlec_id,
zlec_nr,
zlec_do,
zlec_ogran,
awizacje,
awizacja_na_dzien,
termin_zamkniecia,
tresc,
uwagi
FROM zlec
INNER JOIN koord
ON zlec.koord = koord.id
INNER JOIN zlec_adresy
ON zlec.zlec_addres = zlec_adresy.id
INNER JOIN piorytet
ON zlec.priorytet = piorytet.id
INNER JOIN zlec_status
ON zlec.status_zlecenia = zlec_status.id
And the following one which is a ordinary one
Query 2.
SELECT * FROM zlec;
The thing is the first one returns ( affects by executing ) 48 rows where the second query returns 103 rows. What could be the possible cause of this?
I will also show you my dumb of the sql in case you would like to make a run on your own http://pastebin.com/cMPAtxCU .
Subquestion - quite no point starting of with a new question for that because its also connected with the row count affect.
Besides I was wondering how can I get into the first query a count(*) to get the affected rows - it has to be done in sql I cannot use php code for that, probably it would be good to use a limit 1 for the count.
With INNER JOIN, if one of your other tables, koord, zlec_adresy, piorytet and zlec_status is missing a record corresponding to a record in zlec, that record in zlec will not be in the result set. If you want every record in zlec to appear, you have to use LEFT JOIN. Check out:
http://blog.codinghorror.com/a-visual-explanation-of-sql-joins/
For a pretty good explanation.
With your additional inner joins rows might be eliminated. Have you tried adding the inner joins to your "Select * FROM zlec;"?
I've got read-only access to a MySQL database, and I need to loop through the following query about 9000 times, each time with a different $content_path_id. I'm calling this from within a PERL script that's pulling the '$content_path_id's from a file.
SELECT an.uuid FROM alf_node an WHERE an.id IN
(SELECT anp.node_id FROM alf_node_properties anp WHERE anp.long_value IN
(SELECT acd.id FROM alf_content_data acd WHERE acd.content_url_id = $content_path_id));
Written this way, it's taking forever to do each query (approximately 1 minute each). I'd really rather not wait 9000+ minutes for this to complete if I don't have to. Is there some way to speed up this query? Maybe via a join? My current SQL skills are embarrassingly rusty...
This is an equivalent query using joins. It depends what indexes are defined on the tables how this will perform.
If your Perl interface has the notion of prepared statements, you may be able to save some time by preparing once and executing with 9000 different binds.
You could also possibly save time by building one query with a big acd.content_url_id In ($content_path_id1, $content_path_id2, ...) clause
Select
an.uuid
From
alf_node an
Inner Join
alf_node_properties anp
On an.id = anp.node_id
Inner Join
alf_content_data acd
On anp.long_value = acd.id
Where
acd.content_url_id = $content_path_id
Try this extension to Laurence's solution which replaces the long list of OR's with an additional JOIN:
Select
an.uuid
From alf_node an
Join alf_node_properties anp
On an.id = anp.node_id
Join alf_content_data acd
On anp.long_value = acd.id
Join (
select "id1" as content_path_id union all
select "id2" as content_path_id union all
/* you get the idea */
select "idN" as content_path_id
) criteria
On acd.content_url_id = criteria.content_path_id
I have used SQL Server syntax above but you should be able to translate it readily.
MySQL Server Version: Server version: 4.1.14
MySQL client version: 3.23.49
Tables under discussion: ads_list and ads_cate.
Table Relationship: ads_cate has many ads_list.
Keyed by: ads_cate.id = ads_list.Category.
I am not sure what is going on here, but I am trying to use COUNT() in a simple agreggate query, and I get blank output.
Here is a simple example, this returns expected results:
$queryCats = "SELECT id, cateName FROM ads_cate ORDER BY cateName";
But if I modify it to add the COUNT() and the other query data I get no array return w/ print_r() (no results)?
$queryCats = "SELECT ads_cate.cateName, ads_list.COUNT(ads_cate.id),
FROM ads_cate INNER JOIN ads_list
ON ads_cate.id = ads_list.category
GROUP BY cateName ORDER BY cateName";
Ultimately, I am trying to get a count of ad_list items in each category.
Is there a MySQL version conflict on what I am trying to do here?
NOTE: I spent some time breaking this down, item by item and the COUNT() seems to cause the array() to disappear. And the the JOIN seemed to do the same thing... It does not help I am developing this on a Yahoo server with no access to the php or mysql error settings.
I think your COUNT syntax is wrong. It should be:
COUNT(ads_cate.id)
or
COUNT(ads_list.id)
depending on what you are counting.
Count is an aggregate. means ever return result set at least one
here you be try count ads_list.id not null but that wrong. how say Myke Count(ads_cate.id) or Count(ads_list.id) is better approach
you have inner join ads_cate.id = ads_list.category so Count(ads_cate.id) or COUNT(ads_list.id) is not necessary just count(*)
now if you dont want null add having
only match
SELECT ads_cate.cateName, COUNT(*),
FROM ads_cate INNER JOIN ads_list
ON ads_cate.id = ads_list.category
GROUP BY cateName
having not count(*) is null
ORDER BY cateName
all
SELECT ads_cate.cateName, IFNULL(COUNT(*),0),
FROM ads_cate LEFT JOIN ads_list
ON ads_cate.id = ads_list.category
GROUP BY cateName
ORDER BY cateName
Did you try:
$queryCats = "SELECT ads_cate.cateName, COUNT(ads_cate.id)
FROM ads_cate
JOIN ads_list ON ads_cate.id = ads_list.category
GROUP BY ads_cate.cateName";
I am guessing that you need the category to be in the list, in that case the query here should work. Try it without the ORDER BY first.
You were probably getting errors. Check your server logs.
Also, see what happens when you try this:
SELECT COUNT(*), category
FROM ads_list
GROUP BY category
Your array is empty or disappear because your query has errors:
there should be no comma before the FROM
the "ads_list." prefix before COUNT is incorrect
Please try running that query directly in MySQL and you'll see the errors. Or try echoing the output using mysql_error().
Now, some other points related to your query:
there is no need to do ORDER BY because GROUP BY by default sorts on the grouped column
you are doing a count on the wrong column that will always give you 1
Perhaps you are trying to retrieve the count of ads_list per ads_cate? This might be your query then:
SELECT `ads_cate`.`cateName`, COUNT(`ads_list`.`category`) `cnt_ads_list`
FROM `ads_cate`
INNER JOIN `ads_list` ON `ads_cate`.`id` = `ads_list`.`category`
GROUP BY `cateName`;
Hope it helps?