Using LINQ to SQL
db.Products.Where(c => c.ID == 1).Skip(1).Take(1).ToList();
executes
SELECT [t1].[ID], [t1].[CategoryID], [t1].[Name], [t1].[Price], [t1].[Descripti
n], [t1].[IsFeatured], [t1].[IsActive]
FROM (
SELECT ROW_NUMBER() OVER (ORDER BY [t0].[ID], [t0].[CategoryID], [t0].[Name
, [t0].[Price], [t0].[Description], [t0].[IsFeatured], [t0].[IsActive]) AS [ROW
NUMBER], [t0].[ID], [t0].[CategoryID], [t0].[Name], [t0].[Price], [t0].[Descrip
ion], [t0].[IsFeatured], [t0].[IsActive]
FROM [dbo].[Products] AS [t0]
WHERE [t0].[ID] = #p0
) AS [t1]
WHERE [t1].[ROW_NUMBER] BETWEEN #p1 + 1 AND #p1 + #p2
ORDER BY [t1].[ROW_NUMBER]
-- #p0: Input Int (Size = 0; Prec = 0; Scale = 0) [1]
-- #p1: Input Int (Size = 0; Prec = 0; Scale = 0) [1]
-- #p2: Input Int (Size = 0; Prec = 0; Scale = 0) [1]
It's using ROW_NUMBER for pagination... good.
Now, I'm trying to use relationships generated by LINQ to SQL to paginate data. Using the query...
var cat = db.Categories.Where(c => c.ID == 1).SingleOrDefault();
cat.Products.Where(c => c.ID == 1).Skip(1).Take(1).ToList();
SELECT [t0].[ID], [t0].[Name]
FROM [dbo].[Categories] AS [t0]
WHERE [t0].[ID] = #p0
-- #p0: Input Int (Size = 0; Prec = 0; Scale = 0) [1]
-- Context: SqlProvider(Sql2008) Model: AttributedMetaModel Build: 3.5.30729.1
SELECT [t0].[ID], [t0].[CategoryID], [t0].[Name], [t0].[Price], [t0].[Descriptio
n], [t0].[IsFeatured], [t0].[IsActive]
FROM [dbo].[Products] AS [t0]
WHERE [t0].[CategoryID] = #p0
-- #p0: Input Int (Size = 0; Prec = 0; Scale = 0) [1]
-- Context: SqlProvider(Sql2008) Model: AttributedMetaModel Build: 3.5.30729.1
Now the use of ROW_NUMBER and pagination is gone... it's getting all Products where CategoryID = 1... why is it getting ALL rows?
I think its because the category is in memory. You are asking it, implicitly, to get the products of the category. This implicit request for data is for filled, and then in memory (where the category is at this point) the query is executed.
I'm thinking its equivalent to :
var cat = db.Categories.Where(c => c.ID == 1).SingleOrDefault();
var prods = db.Products.Where(c => c.ID == 1).ToList();
var r = prods.Where(p.CategoryID == cat.ID).Skip(1).Take(1);
Note the significance, what if cat changes in memory? The size of the collection could vary.
NOTE: Thanks for the headache :)
have you tried:
var cat = db.Categories.Where(c => c.ID == 1);
var prod = cat.Products.Where(c => c.ID == 1).Skip(1).Take(1).ToList();
You haven't assigned the output of your second LINQ query. So 'cat' is still the first query only.
Related
I'm trying to convert this SQL Query into Core EF:
SELECT w.IdShippingBatch, w.BookingNumber, COUNT(c.IdShippingOrder) AS ShippingOrders, w.CreatedOn, w.ModifiedOn
FROM dbo.Shipping`enter code here`Batch AS w LEFT OUTER JOIN
dbo.ShippingOrders AS c ON w.IdShippingBatch = c.IdShippingBatch
WHERE (w.IdCompany = 2) AND (w.IdDealer = 1)
GROUP BY w.IdShippingBatch, w.BookingNumber, w.CreatedOn, w.ModifiedOn
I have tried multiple solutions, including several here. My latest attempt looks like:
var data = (from w in _context.ShippingBatch
join c in _context.ShippingOrders on w.IdShippingBatch equals c.IdShippingBatch into t1
where w.IdCompany == idCompany && w.IdDealer == idDealer
from t2 in t1.DefaultIfEmpty()
group t2 by new { w.IdShippingBatch, w.BookingNumber, w.CreatedOn, w.ModifiedOn } into t3
select new ShippingBatchDTO
{
IdShippingBatch = t3.Key.IdShippingBatch,
BookingNumber = t3.Key.BookingNumber,
ShippingOrders = t3.Count(),
CreatedOn = t3.Key.CreatedOn,
ModifiedOn = t3.Key.ModifiedOn
});
I have also tried adding t3.count(m => m.something != null), but that throws an error.
One major point of EF is to map the relationship between entities so that you can leverage LINQ and let EF compose an SQL query rather than trying to replace SQL with LINQ-QL.
If your ShippingBatch is mapped with a collection of ShippingOrders...
var batches = _context.ShippingBatch
.Where(x => x.IdCompany == idCompany && x.IdDealer == idDealer)
.Select(x => new ShippingBatchDTO
{
IdShippingBatch = x.IdShippingBatch,
BookingNumber = x.BookingNumber,
ShippingOrders = x.ShippingOrders.Count(),
CreatedOn = x.CreatedOn,
ModifiedOn = x.ModifiedOn
}).ToList();
If your ShippingBatch does not have a collection of ShippingOrders, but your ShippingOrder reference an optional ShippingBatch.
var batches = _context.ShippingOrder
.Where(x => x.ShippingBatch != null
&& x.ShippingBatch.IdCompany == idCompany
&& x.ShippingBatch.IdDealer == idDealer)
.GroupBy(x => x.ShippingBatch)
.Select(x => new ShippingBatchDTO
{
IdShippingBatch = x.Key.IdShippingBatch,
BookingNumber = x.Key.BookingNumber,
ShippingOrders = x.Count(),
CreatedOn = x.Key.CreatedOn,
ModifiedOn = x.Key.ModifiedOn
}).ToList();
That should hopefully get you moving in the right direction. If not, expand your question to include details of what you are seeing, and what you expect to see along with definitions for the applicable entities.
How can I translate this to a lambda expression? Can anyone please help?
SELECT
p.*
FROM
db.MainProduct p
WHERE
p.id IN (SELECT ms.MainProductId
FROM db.MainProductToSupplierProduct ms)
AND (p.description LIKE '%' + #filter + '%'
OR Coalesce(#filter,'') = '')
Or in query syntax:
var ans = from p in db.MainProduct where (from ms in db.MainProductToSupplierProduct select ms.MainProductId).Contains(p.id) && (filter == "" || p.description.Contains(filter)) select p;
Not sure that is the most efficient way, a less literal translation would use a join:
var ans = from p in db.MainProduct join ms in db.MainProductToSupplierProduct on p.id equals ms.MainProductId where filter == "" || p.description.Contains(filter) select p;
This is a left semi join and the best way to implement that is probably an EXISTS in SQL - it may be faster than join:
var ans = from p in db.MainProduct where db.MainProductToSupplierProduct.Any(ms => ms.MainProductId == p.id) && (filter == "" || p.description.Contains(filter)) select p;
Below code can help you out
var filteredMainProduct= MainProduct.Where(t => MainProductToSupplierProduct.Any(z => z.MainProductId == t.id) && #filter != null ? t.description.Contains(#filter) : t.FareBasisDescription.Contains(""));
I have stuck in this issue from the last two days.
Please help.
I want to assign the following query .
$qr = "( select subconfigcode.field_subconfigcode_value AS configcode FROM node node LEFT JOIN field_data_field_select_parent_configuratio select_parent_configuratio ON node.nid = select_parent_configuratio.entity_id AND (select_parent_configuratio.entity_type = node AND select_parent_configuratio.deleted = 0) LEFT JOIN node select_parent_configuratio_node ON select_parent_configuratio.field_select_parent_configuratio_nid = select_parent_configuratio_node.nid LEFT JOIN field_data_field_subconfigcode subconfigcode ON select_parent_configuratio_node.nid = subconfigcode.entity_id AND (subconfigcode.entity_type = 'node' AND subconfigcode.deleted = '0') WHERE (( (select_parent_configuratio.field_select_parent_configuratio_nid = node_field_data_field_select_parent_configuratio.nid) )AND(( (node.status = '1') AND (node.type IN ('offering')) ))) ORDER BY node.created DESC, configcode ASC LIMIT 1 OFFSET 0)";
to
one view's field value.
I have used the following code.
function general_views_query_alter(&$view, &$query) {
$qr = " ( select subconfigcode.field_subconfigcode_value AS configcode FROM node node LEFT JOIN field_data_field_select_parent_configuratio select_parent_configuratio ON node.nid = select_parent_configuratio.entity_id AND (select_parent_configuratio.entity_type = node AND select_parent_configuratio.deleted = 0) LEFT JOIN node select_parent_configuratio_node ON select_parent_configuratio.field_select_parent_configuratio_nid = select_parent_configuratio_node.nid LEFT JOIN field_data_field_subconfigcode subconfigcode ON select_parent_configuratio_node.nid = subconfigcode.entity_id AND (subconfigcode.entity_type = 'node' AND subconfigcode.deleted = '0') WHERE (( (select_parent_configuratio.field_select_parent_configuratio_nid = node_field_data_field_select_parent_configuratio.nid) )AND(( (node.status = '1') AND (node.type IN ('offering')) ))) ORDER BY node.created DESC, configcode ASC LIMIT 1 OFFSET 0)";
$query->add_where(1, "node_field_data_field_select_parent_configuratio__field_data_field_subconfigcode.field_subconfigcode_value", $qr);
}
But, it is returning the following where query.
where node_field_data_field_select_parent_configuratio__field_data_field_subconfigcode.field_subconfigcode_value = '( select subconfigcode.field_subconfigcode_value AS configcode FROM node node LEFT JOIN field_data_field_select_parent_configuratio select_parent_configuratio ON node.nid = select_parent_configuratio.entity_id AND (select_parent_configuratio.entity_type = node AND select_parent_configuratio.deleted = 0) LEFT JOIN node select_parent_configuratio_node ON select_parent_configuratio.field_select_parent_configuratio_nid = select_parent_configuratio_node.nid LEFT JOIN field_data_field_subconfigcode subconfigcode ON select_parent_configuratio_node.nid = subconfigcode.entity_id AND (subconfigcode.entity_type = \'node\' AND subconfigcode.deleted = \'0\') WHERE (( (select_parent_configuratio.field_select_parent_configuratio_nid = node_field_data_field_select_parent_configuratio.nid) )AND(( (node.status = \'1\') AND (node.type IN (\'offering\')) ))) ORDER BY node.created DESC, configcode ASC LIMIT 1 OFFSET 0) ')
I want to get query without the single quote assigned for sub query and remove extra slashed added to each value.
Please help.
Answer :
Direct query is not applicable for assignment purpose in the add_where condition.
For that, I have generated the query object using.
function general_views_query_alter(&$view, &$query) {
$subQuery = db_select('node', 'node'); $subQuery->leftJoin('field_data_field_select_parent_configuratio', 'select_parent_configuratio ', 'node.nid = select_parent_configuratio .entity_id');
$subQuery->condition('select_parent_configuratio.entity_type', 'node', '=');
$subQuery->condition('select_parent_configuratio.deleted', '0', '=');
$subQuery->leftJoin('node', 'select_parent_configuratio_node', 'select_parent_configuratio.field_select_parent_configuratio_nid = select_parent_configuratio_node.nid');
$subQuery->leftJoin('field_data_field_subconfigcode', 'subconfigcode', 'select_parent_configuratio_node.nid = subconfigcode.entity_id');
$subQuery->condition('subconfigcode.entity_type', 'node', '=');
$subQuery->condition('subconfigcode.deleted', '0', '=');
$subQuery->where("select_parent_configuratio.field_select_parent_configuratio_nid = node_field_data_field_select_parent_configuratio.nid");
$subQuery->condition('node.status', "1", '=');
$subQuery->condition('node.type', array('offering'), 'IN');
$subQuery->orderBy('configcode');
$subQuery->addField('subconfigcode', 'field_subconfigcode_value', 'configcode');
//$subQuery->range(0, 1);
$query->add_where($group,'node_field_data_field_select_parent_configuratio__field_data_field_subconfigcode.field_subconfigcode_value',$subQuery,'in');
}
Using this, I am able to generate it the query and assignment to value of the variable.
I need a Linq To SQL Query that Counts the rows of a table that fall within time brackets of an arbitrary interval. The Table has a single DateTime field.
Google got me to this SQL (http://ebersys.blogspot.ca/2010/12/sql-group-datetime-by-arbitrary-time.html)
declare #interval int
set #interval = 5
select convert(varchar(8), DTColumn, 1)+' '
+convert(varchar(2), datepart(hh, DTColumn))+':'
+convert(varchar(2), datepart(mi, DTColumn)/#interval*#interval)
, count(*)
from the_table
group by convert(varchar(8), DTColumn, 1)+' '
+convert(varchar(2), datepart(hh, DTColumn))+':'
+convert(varchar(2), datepart(mi, DTColumn)/#interval*#interval)
I could move the query to SQL but prefer to keep the DAL consistent LinqToSQL. The best I could come up with is this, but errors with "Tick is not supported in SQL"
int interval = Convert.ToInt32(uxTxtInterval.Text);
var q = (from d in dc.theTable.OrderBy(o => o.dmMe).ThenBy(o => o.dmWith).ThenBy(o => o.dmCreatedAt)
group d by
(
Math.Floor(new TimeSpan(d.dmCreatedAt.Ticks).TotalMinutes / interval)
)
into grpTable
select
new
{
time = grpTable.Key, // ?? needs to be the DateTime not ticks
count = grpTable.Count()
}
);
Any help greatly appreciated :-)
Thanks!
You can use SqlMethods.DateDiffMinute to get the time buckets:
var startdate = new DateTime(1900,1,1); // An arbitrary date
int interval = Convert.ToInt32(uxTxtInterval.Text);
var q = (from d in dc.theTable.OrderBy(o => o.dmMe).ThenBy(o => o.dmWith).ThenBy(o => o.dmCreatedAt)
group d by
(
SqlMethods.DateDiffMinute(startdate, d.dmCreatedAt) / interval
)
into grpTable
select
new
{
time = grpTable.Key,
count = grpTable.Count()
}
);
Please correct the query
IN PL/SQL
SELECT a.MENU_ID, a.menu_label, a.menu_value
FROM tbl_ims_menu a, TBL_IMS_ROLE_ASSIGNED_MENU b,TBL_IMS_USER_ROLE_PRIVILEGES c
WHERE a.menu_id = b.menu_id AND b.urole_id = c.granted_role
AND c.user_id = '3' AND a.menu_master <> '0'
AND a.menu_status = 'Active'
GROUP BY a.menu_id, a.menu_label, a.menu_value
query is working fine there is some issue when rewrite in Entity framework
check the following query
List<TBL_IMS_MENU> listSubMenu = (from m in db.TBL_IMS_MENU
join ra in db.TBL_IMS_ROLE_ASSIGNED_MENU on m.MENU_ID
equals ra.MENU_ID
join rp in db.TBL_IMS_USER_ROLE_PRIVILEGES on ra.UROLE_ID
equals rp.GRANTED_ROLE
where rp.USER_ID == UserID
group m by m.MENU_ID
into g select g).ToList();
if I used Var instead of List then how to fire loop?
I think you need to remove your join statements - and just use the where like you do in raw SQL query:
var qry = (from a in db.TBL_IMS_MENU
from b in db.TBL_IMS_ROLE_ASSIGNED_MENU
from c in db.TBL_IMS_USER_ROLE_PRIVILEGES
where c.USER_ID == UserID
where b.UROLE_ID == c.GRANTED_ROLE
where a.MENU_ID == b.MENU_ID
where a.menu_status == "Active"
where a.menu_master != "0"
select a)
.GroupBy(c => c.menu_id)
.ThenBy(c => c.menu_label)
.ThenBy(c => c.menu_value)
.ToList();
Try something like this:
var listSubMenu = (from m in db.TBL_IMS_MENU
join ra in db.TBL_IMS_ROLE_ASSIGNED_MENU on m.MENU_ID
equals ra.MENU_ID
join rp in db.TBL_IMS_USER_ROLE_PRIVILEGES on ra.UROLE_ID
equals rp.GRANTED_ROLE
where rp.USER_ID == UserID
group m by new { m.MENU_ID, m.menu_label, m.menu_value }
into g select g).ToList();
foreach(var groupItem in listSubMenu)
{
// go through groups like this - groupItem.Key.MENU_ID
foreach(var menuItem in grouItem)
{
//go through each item in group like this - menuItem.GRANTED_ROLE
}
}