I am trying to use .UnionAll method in go-pg library for golang.
var model []Customer
q0 := db.Model(&model).Where("name = ?", name0).Limit(4)
q1 := db.Model(&model).Where("name = ?", name1).Limit(3)
var result []Customer
if err := q0.UnionAll(q1).Limit(1).Select(&result); !as.NoError(err) {
return
}
This code produces the query:
(SELECT "customer"."id", "customer"."name" FROM customers AS "customer" WHERE (name = 'customer 1deificatory zonoid reprepare alacrify serenissime')
LIMIT 1)
UNION ALL
(SELECT "customer"."id", "customer"."name" FROM customers AS "customer" WHERE (name = 'customer 2fordless ferroboron radiability dandizette smutch'
LIMIT 3)
)
But I expect it to be:
(SELECT "customer"."id", "customer"."name" FROM customers AS "customer" WHERE (name = 'customer 1deificatory zonoid reprepare alacrify serenissime')
LIMIT 4)
UNION ALL
(SELECT "customer"."id", "customer"."name" FROM customers AS "customer" WHERE (name = 'customer 2fordless ferroboron radiability dandizette smutch')
LIMIT 3)
LIMIT 1
So how to use go-pg to get raw SQL query which I expect?
The thing is I can't apply the Limit 1 expression to the whole query for some reason.
Also, my Limit 4 is not applied correctly to the first union all member.
My whole code is here.
I believe this query does the trick for you.
if err := db.Model().With("union_q", q0.UnionAll(q1)).Table("union_q").Limit(1).Select(&result); !as.NoError(err) {
return
}
The query isn't exactly what you wanted to be and as far as I know, the current version of go-pg can't generate that query. But this query does exactly what you wanted.
Related
I need to count how many records in the tableA are not in the tableA, how to do this with LINQ?
with SQL I do the following way
select count(*) as total from produtoitemgrade g
where g.id not in (select idprodutograde from produtoestoque where idProduto = 12)
and g.idProduto = 12
my linq code so far.
var temp = (from a in Produtoitemgrades
join b in Produtoestoques on a.IdUnico equals b.IdUnicoGrade into g1
where g1.Count(y => y.IdProduto == 12)>0 && !g1.Any()
select a).ToList();
I tried to follow that example LINQ get rows from a table that don't exist in another table when using group by?
but an error occurs when running, how can I do this?
Thanks!
Your query should looks like the following, if you want to have the same SQL execution plan:
var query =
from a in Produtoitemgrades
where !Produtoestoques.Where(b => a.IdUnico == b.IdUnicoGrade && b.idProduto == 12).Any()
&& a.idProduto == 12
select a;
var result = query.Count();
I am very new to SQL and I do not know much about writing code in the different DBMS. I am trying to write a report in our school's MOODLE platform, which uses postgresql, using a configurable report found here. However, the code does not work in postgresql. In particular, how do I rewrite those lines with variable assignments like #prevtime := to make the code work in postgresql?
Here is the complete code from the link.
SELECT
l.id,
l.timecreated,
DATE_FORMAT(FROM_UNIXTIME(l.timecreated),'%d-%m-%Y') AS dTime,
#prevtime := (SELECT MAX(timecreated) FROM mdl_logstore_standard_log
WHERE userid = %%USERID%% AND id < l.id ORDER BY id ASC LIMIT 1) AS prev_time,
IF (l.timecreated - #prevtime < 7200, #delta := #delta + (l.timecreated-#prevtime),0) AS sumtime,
l.timecreated-#prevtime AS delta,
"User" AS TYPE
FROM prefix_logstore_standard_log AS l,
(SELECT #delta := 0) AS s_init
# CHANGE UserID
WHERE l.userid = %%USERID%% AND l.courseid = %%COURSEID%%
%%FILTER_STARTTIME:l.timecreated:>%% %%FILTER_ENDTIME:l.timecreated:<%%
This is supposed to report the time spent by students in courses in MOODLE.
I assume the original query was written for MySQL. You haven't explained what the query actually does, but the #prevtime hack is usually a workaround for missing window functions, so most probably this can be done using lag() in Postgres, something along the lines:
select l.id,
l.timecreated,
to_char(to_timestamp(l.timecreated), 'dd-mm-yyyy') as dtime,
lag(timecreated) over w as prev_time,
l.timecreated - lag(timecreated) over w as delta,
'User' as type,
FROM prefix_logstore_standard_log AS l
window w as (partition by userid order by id)
WHERE l.userid = %%USERID%%
AND l.courseid = %%COURSEID%%
Is it possible to do orderby expression using linq query expression based on dynamic string parameter? because the query i have is producing weird SQL query
my linq:
var product = from prod in _context.Products
join cat in _context.Categories on prod.CategoryId equals cat.CategoryId
join sup in _context.Suppliers on prod.SupplierId equals sup.SupplierId
orderby sortParam
select new ProductViewModel
{
ProductName = prod.ProductName,
ProductId = prod.ProductId,
QuantityPerUnit = prod.QuantityPerUnit,
ReorderLevel = prod.ReorderLevel,
UnitsOnOrder = prod.UnitsOnOrder,
UnitPrice = prod.UnitPrice,
UnitsInStock = prod.UnitsInStock,
Discontinued = prod.Discontinued,
Category = cat.CategoryName,
Supplier = sup.CompanyName,
CategoryId = cat.CategoryId,
SupplierId = sup.SupplierId
};
where var sortParam = "prod.ProductName"
The code above produces weird sql where order by sortParam is being converted to (SELECT 1). Full query catched by sql profiler below:
exec sp_executesql N'SELECT [prod].[ProductName], [prod].[ProductID], [prod].[QuantityPerUnit], [prod].[ReorderLevel], [prod].[UnitsOnOrder], [prod].[UnitPrice], [prod].[UnitsInStock], [prod].[Discontinued], [cat].[CategoryName] AS [Category], [sup].[CompanyName] AS [Supplier], [cat].[CategoryID], [sup].[SupplierID]
FROM [Products] AS [prod]
INNER JOIN [Categories] AS [cat] ON [prod].[CategoryID] = [cat].[CategoryID]
INNER JOIN [Suppliers] AS [sup] ON [prod].[SupplierID] = [sup].[SupplierID]
ORDER BY (SELECT 1)
OFFSET #__p_1 ROWS FETCH NEXT #__p_2 ROWS ONLY',N'#__p_1 int,#__p_2 int',#__p_1=0,#__p_2=10
I'm seeing a lot of people doing linq order by using dynamic parameter but all of them use lambda not query expression, please enlighten me
As was already mentioned, you are passing a string value instead of an expression that reflects the column name. There are options for what you want however, see for example here.
So the query below is probably not the most efficient, buy still, I am wondering why it is returning no result, even though the SQL counterpart does. There is no error, I am just getting no result. Is it maybe not the correct equivalent for the query I wrote in MySQL?
This is the JPA JPQL.
Query query = em.createQuery("SELECT sub FROM Subscription sub WHERE "
+ "sub.isSuspended = 0 AND "
+ "(SELECT i FROM Invoice i WHERE i.dateDue < CURRENT_DATE AND i.datePaid IS NULL "
+ "GROUP BY i HAVING COUNT(i.idInvoice) > 2) MEMBER OF sub.invoices");
And this is the SQL from MySQL.
SELECT * from subscription
WHERE subscription.is_suspended = 0 AND id_subscription IN
(SELECT id_subscription FROM invoice
WHERE date_due < CURDATE() AND date_paid IS NULL
GROUP BY id_subscription
HAVING COUNT(*) > 2)
The two queries are not the same. To use the actual query use the NativeQuery createNativeQuery() instead of Query.
In your case the JPA version seems to have syntax errors.
After the AND you are missing the IN operator.
In the nested query you are selecting i instead of something like i.idInvoice
The JPA query should look like
SELECT sub FROM Subscription sub
WHERE sub.isSuspended = 0
AND sub.idSubscription IN
(SELECT i.idInvoice
FROM Invoice i
WHERE i.dateDue < CURRENT_DATE AND i.datePaid IS NULL
GROUP BY i.idInvoice
HAVING COUNT(i.idInvoice) > 2);
Table1 :
userid name address
1 venkat srinagr
2 venkatesh sainagar
Table2:
id userid lat lon
1 1 14.000 15.000
2 2 14.3526 15.3698
by passing "venkat" as parameter then need to pull all matching records and his userid,name,lat,lon.
in above table1 "venkat" contains in both rows then need to pull 2 records.how to get userid,name,lat,lon for all matching rows..
for sigle record i am able to get.but there are multiple rows how to get please tell me....
var result = from p in cxt.Table2
where p.Table1.Name.Contains(name)
select new
{
p.Users.User_Id,p.Users.Name,p.Latitude,p.Longitude
};
Im sure someone will say this is not the most effective way but this is how i would do it.
string InputString = "venkat";
var tab =(from a in db.tablea
from b in db.tableb
where a.userid == b.userid && a.name == InputString
select new
{
UserID = a.userid,
Username = a.name,
Latitude = b.lat,
Longditude = b.lon
}).FirstOrDefault();
FirstOrDefault() is only if you want to force only one output or null,
if you want a collection of some sort, then just remove it.