I'm new in Linq and I'm trying to optimize some queries and I don't have any idea if it is possible for this queries:
var cSRez = (from l in MyTable
where l.Name == "dcc" && l.Service == "Main"
orderby l.Time descending
select l.Value).FirstOrDefault();
var cDRez = (from l in MyTable
where l.Name == "dcc" && l.Service == "DB"
orderby l.Time descending
select l.Value).FirstOrDefault();
var dSRez = (from l in MyTable
where l.Name == "ddc" && l.Service == "Main"
orderby l.Time descending
select (long?)l.Value).FirstOrDefault();
var dDRez = (from l in MyTable
where l.Name == "ddc" && l.Service == "DB"
orderby l.Time descending
select (long?)l.Value).FirstOrDefault();
var mSRez = (from l in MyTable
where l.Name == "mc" && l.Service == "Main"
orderby l.Time descending
select l.Value).FirstOrDefault();
var mDRez = (from l in MyTable
where l.Name == "mc" && l.Service == "DB"
orderby l.Time descending
select l.Value).FirstOrDefault();
to become a single one.
I was thinking about row_number() over(partition by... (SQL) but I don't think this is the best idea for doing this.
It is possible to collapse this six separate queries into a single one?
You'd need to group on the Name and Service and then filter on the specific pairs you want then select the Name and Service and the Value from the First match. Note that any pairs that do not exist will not be represented in the results and you'd have to handle that when you pull the values out.
var results = (from l in MyTable
group l by new {l.Name, l.Service} into grp
where (grp.Key.Name == "dcc" && grp.Key.Service == "Main")
|| (grp.Key.Name == "dcc" && grp.Key.Service == "DB")
|| ....
select new
{
grp.Key,
Value = grp.OrderByDescending(x => x.Time).Select(x => x.Value).First()
}).ToDictionary(x => x.Key, x => x.Value);
Then to pull out the results
results.TryGetValue(new { Name = "dcc", Service = "Main" }, out var cSRez);
I am not sure how EF would translate this query to SQL, but I would try this approach:
var rawData = MyTable
.Where(l => (l.Name=="dcc" || l.Name=="ddc" || l.Name=="mc") && (l.Service=="Main" || l.Service=="Db"))
.GroupBy(l => new { l.Name, l.Service })
.Select(g => g.OrderByDescending(l => l.Time).First())
.ToList();
This should yield up to six rows of interest to your program. Now you can retrieve each row by specifying the specific combination of Name and Service:
var cSRez = rawData.FirstOrDefault(l => l.Name == "dcc" && l.Service == "Main");
var cDRez = rawData.FirstOrDefault(l => l.Name == "dcc" && l.Service == "DB");
var dSRez = rawData.FirstOrDefault(l => l.Name == "ddc" && l.Service == "Main");
var dDRez = rawData.FirstOrDefault(l => l.Name == "ddc" && l.Service == "DB");
var mSRez = rawData.FirstOrDefault(l => l.Name == "mc" && l.Service == "Main");
var mDRez = rawData.FirstOrDefault(l => l.Name == "mc" && l.Service == "DB");
Note that the six queries on rawData are performed in memory on a list of fixed size of up to six items, so they are not costing you additional round-trips to RDBMS.
I am not sure if this will execute faster as a single query or not, as the query is somewhat complex, so I think it may depend on server side query time versus query setup and data transmission time.
You can convert into a single query that gathers all the answers at once, and then break that answer up for each variable.
This first answer takes the result and converts into a double nested Dictionary for the values and then pulls the variables out of the Dictionary:
var ansd = (from l in MyTable
where new[] { "dcc", "ddc", "mc" }.Contains(l.Name) && new[] { "Main", "DB" }.Contains(l.Service)
group l by new { l.Name, l.Service } into ag
select new {
ag.Key.Name,
ag.Key.Service,
Value = ag.OrderByDescending(l => l.Time).First().Value
})
.GroupBy(nsv => nsv.Name)
.ToDictionary(nsvg => nsvg.Key, nsvg => nsvg.ToDictionary(nsv => nsv.Service, arv => arv.Value));
long? cSRez = null, cDRez = null, dSRez = null, dDRez = null, mSRez = null, mDRez = null;
if (ansd.TryGetValue("dcc", out var td)) td.TryGetValue("Main", out cSRez);
if (ansd.TryGetValue("dcc", out td)) td.TryGetValue("DB", out cDRez);
if (ansd.TryGetValue("ddc", out td)) td.TryGetValue("Main", out dSRez);
if (ansd.TryGetValue("ddc", out td)) td.TryGetValue("DB", out dDRez);
if (ansd.TryGetValue("mc", out td)) td.TryGetValue("Main", out mSRez);
if (ansd.TryGetValue("mc", out td)) td.TryGetValue("DB", out mDRez);
Given that there are only six answers, creating Dictionarys for them may be overkill. Instead, you can just (sequentially) find the matching answers:
var ansl = (from l in MyTable
where new[] { "dcc", "ddc", "mc" }.Contains(l.Name) && new[] { "Main", "DB" }.Contains(l.Service)
group l by new { l.Name, l.Service } into ag
select new {
ag.Key.Name,
ag.Key.Service,
Value = ag.OrderByDescending(l => l.Time).First().Value
})
.ToList();
var cSRez = ansl.FirstOrDefault(ansv => ansv.Name == "dcc" && ansv.Service == "Main");
var cDRez = ansl.FirstOrDefault(ansv => ansv.Name == "dcc" && ansv.Service == "DB");
var dSRez = ansl.FirstOrDefault(ansv => ansv.Name == "ddc" && ansv.Service == "Main");
var dDRez = ansl.FirstOrDefault(ansv => ansv.Name == "ddc" && ansv.Service == "DB");
var mSRez = ansl.FirstOrDefault(ansv => ansv.Name == "mc" && ansv.Service == "Main");
var mDRez = ansl.FirstOrDefault(ansv => ansv.Name == "mc" && ansv.Service == "DB");
Just put your query in a private method that takes an Exression and returns Value and call it for each variable (e.g. cDRez, cSRez etc) simply passing different expressions.
private Value GetValue(Expression<Func<MyTable, bool>> filter) {
return MyTable.Where(filter).OrderByDescending(o => o.Time).Select(s => s.Value).FirstOrDefault();
}
Call it like with different filters for each variable:
var cSRez = GetValue(l => l.Name == "dcc" && l.Service == "Main");
var cDRez = GetValue(l => l.Name == "dcc" && l.Service == "DB");
var dSRez = GetValue(l => l.Name == "ddc" && l.Service == "Main");
var dDRez = GetValue(l => l.Name == "ddc" && l.Service == "DB");
var mSRez = GetValue(l => l.Name == "mc" && l.Service == "Main");
var mDRez = GetValue(l => l.Name == "mc" && l.Service == "DB");
Related
var _query = _dbContext.CashVoucherDetails
.Where(x => x.CreationDate.Date >= From.Date && x.CreationDate.Date <= To.Date && (x.Type == Common.TransactionType.CPV || x.Type == Common.TransactionType.BPV) && x.CompanyCode == BranchCode && x.DebitAmount > 0)
.GroupBy(v => new { v.AccountCode})
.Select(g => new
{
AccountCode = g.Key.AccountCode,
});
var balances = _dbContext.CashVoucherDetails
.Where(x => x.CreationDate.Date <= To.Date && x.CompanyCode == BranchCode)
//.Exist(_query.Account) (I want only account which exist in upper query)
.GroupBy(v => new { v.AccountCode})
.Select(g => new
{
AccountCode = g.Key.AccountCode,
Balance = g.Sum(x => x.DebitAmount - x.CreditAmount),
});
I want to use something like EXIST here in first query I have some specific accounts and in 2nd query I want to calculate balances of those accounts.
Can you please tell how I can use Exist function in LINQ.
Thank you.
I want this query to be implemented in LINQ:
SELECT `c`.`AccountCode`, `c`.`CompanyCode` AS `LocationCode`, COALESCE(SUM(`c`.`DebitAmount` - `c`.`CreditAmount`), 0) AS `Balance`
FROM `CashVoucherDetails` AS `c`
WHERE (CONVERT(`c`.`CreationDate`, date) <= '2022-12-20') AND (`c`.`CompanyCode` = '002') and `c`.`AccountCode` IN
(
SELECT `c`.`AccountCode`
FROM `CashVoucherDetails` AS `c`
WHERE ((((CONVERT(`c`.`CreationDate`, date) >= '2022-12-20') AND (CONVERT(`c`.`CreationDate`, date) <= '2022-12-20')) AND `c`.`Type` IN ('CPV', 'BPV')) AND (`c`.`CompanyCode` = '002')) AND (`c`.`DebitAmount` > 0)
GROUP BY `c`.`AccountCode`
)
GROUP BY `c`.`AccountCode`, `c`.`CompanyCode`;
you can use Contains or Any.
_dbContext.CashVoucherDetails
.Where(x => x.CreationDate.Date <= To.Date && x.CompanyCode == BranchCode)
.Where(x => _query.Select(q => q.AccountCode).Contains(x.AccountCode))
Or
.Where(x => _query.Any(q => q.AccountCode == x.AccountCode))
Maybe something like that
var balances = _dbContext.CashVoucherDetails
.Where(x => x.CreationDate.Date <= To.Date && x.CompanyCode == BranchCode && _query.Any(q => q.AccountCode == x.AccountCode))
.GroupBy(v => new { v.AccountCode})
.Select(g => new
{
AccountCode = g.Key.AccountCode,
Balance = g.Sum(x => x.DebitAmount - x.CreditAmount),
});
I need to convert this SQL:
SELECT
sb.Id AS id,
sb.name as name,
sb.age AS age,
sb.BirthDay as BirthDay,
su.UnitId AS unitId,
sb.WorkedInDodo AS workedInDodo,
sb.RelativesWorkedInDodo AS relativesWorkedInDodo,
sb.PhoneNumber AS phoneNumber,
sb.Email AS email,
sb.DeliveryCheck AS deliveryCheck,
sb.RestaurantCheck AS restaurantCheck,
sb.StandardsRatingCheck as standardsRatingCheck,
sb.SocialNetwork AS socialNetwork,
sb.SocialNetworkId AS socialNetworkId,
sb.socialNetworkScreenName AS socialNetworkScreenName,
sb.SourceOfInformationAboutSecretBuyers AS SourceOfInformationAboutSecretBuyers,
sb.suitable AS suitable,
sb.SocialNetworkMessagingEnable as socialNetworkMessagingEnable,
sb.IsInGroup as isInGroup,
sb.IsKeyWord as IsKeyWord,
sb.IsBanned as IsBanned,
sb.IsFraud as IsFraud,
sb.LastUnitsUpdateUtcDate as lastUnitsUpdateUtcDate,
sb.Comments as comments,
sb.MessagingApproval as messagingApproval,
sb.ProcessDataApproval as processDataApproval,
sb.CreatedDateTimeUtc AS createdDateTimeUtc,
sb.ModifiedDateTineUTC AS modifiedDateTime,
sb.Country AS country,
sb.PhoneNumberEditedUtc AS PhoneNumberEditedUtc
FROM (select * from
(SELECT s.*,
IF(s.LastSearchMessageDateUtc is null, 0, 1) as searched,
IF(cc.Id is null, 0, 1) as onCheck
FROM secretbuyers s
JOIN secretbuyerunits sbu ON sbu.SecretBuyerId = s.Id
LEFT JOIN outgoingMessageQueue mq ON mq.Type = 1 AND mq.VkUserId = s.SocialNetworkId and mq.State in (1,2)
LEFT JOIN checkcandidates cc ON cc.SecretBuyerId = s.id AND cc.State IN (1,4) AND cc.Date >= #p_checkBeginDateTime AND cc.Date <= #p_checkEndDateTime
WHERE sbu.UnitId = #p_unitId
AND (s.LastSearchMessageDateUtc is null OR s.LastSearchMessageDateUtc < #p_lastSearchMessageDateUtcLimit)
AND ((#p_deliveryCheck = true AND s.DeliveryCheck = true) OR (#p_restaurantCheck = true AND s.RestaurantCheck = true) OR (#p_standardsRatingCheck = true AND s.StandardsRatingCheck = true))
AND s.Suitable = true
AND s.IsRemove = false
AND mq.Id is null
AND s.IsBanned = false
AND s.IsFraud = false
AND s.IsAutoSearchable = true
group by s.Id
Order By onCheck ASC, searched asc, s.LastSearchMessageDateUtc asc) as temp
LIMIT #p_count) AS sb
JOIN secretbuyerunits su ON su.SecretBuyerId = sb.Id;
to EF Core 3.0 linq. The main problem is left joins. At first I've tried to do it like this:
private async Task<IEnumerable<MysteryShopper>> FindMysteryShoppers(
SearchMysteryShoppersParameters searchParameters, CancellationToken ct)
{
var lastSearchEdge = _nowProvider.UtcNow().Date.AddDays(-3);
bool shouldHaveDeliveryCheckMark = ShouldHaveDeliveryCheckMark(searchParameters.SearchType);
bool shouldHaveRestaurantCheckMark = ShouldHaveRestaurantCheckMark(searchParameters.SearchType);
bool shouldHaveStandardsCheckMark = ShouldHaveStandardsCheckMark(searchParameters.SearchType);
var lastCheckupEdgeDate = searchParameters.CheckupDates.Max().AddDays(-30);
return await _ratingsContext.SecretBuyers.AsNoTracking().Where(ms => !ms.IsBanned &&
!ms.IsFraud
&& ms.IsAutoSearchable
&& ms.Suitable
&& !ms.IsRemove
&& ms.SocialNetworkMessagingEnable
&& (ms.LastSearchMessageDateUtc == null
|| ms.LastSearchMessageDateUtc < lastSearchEdge)
)
.Where(ms => !shouldHaveDeliveryCheckMark && ms.DeliveryCheck)
.Where(ms => !shouldHaveRestaurantCheckMark && ms.RestaurantCheck)
.Where(ms => !shouldHaveStandardsCheckMark && ms.StandardsRatingCheck)
.Where(ms => ms.MysteryShopperUnits
.Any(u => searchParameters.UnitIds.Contains(u.UnitId))
)
.GroupJoin(_ratingsContext.Checkups.AsNoTracking().Where(cc => !_cancelledStates.Contains(cc.State)), ms => ms.Id,
cc => cc.SecretBuyerId, (ms, cc) => new
{
MysteryShopper = ms,
LastCheckupDate = cc
.Max(c => c.Date)
}
)
.GroupJoin(_ratingsContext.Messages.AsNoTracking().Where(m =>
m.Type == OutgoingMessageType.CandidateSearch
&& (m.State == OutgoingMessageState.Sending || m.State == OutgoingMessageState.Waiting)),
ms => ms.MysteryShopper.SocialNetworkId,
m => m.VkUserId,
(ms, m) =>
new {ms.MysteryShopper, ms.LastCheckupDate, HasPendingMessages = m.Any()})
.Where(ms => !ms.HasPendingMessages)
.Where(ms => ms.LastCheckupDate < lastCheckupEdgeDate)
.OrderBy(ms => ms.LastCheckupDate != null)
.ThenBy(ms => ms.MysteryShopper.LastSearchMessageDateUtc != null)
.ThenBy(ms => ms.MysteryShopper.LastSearchMessageDateUtc)
.Select(ms => ms.MysteryShopper)
.ToArrayAsync(ct);
}
After running this query I got error:
... by 'NavigationExpandingExpressionVisitor' failed. This may indicate either a bug or a limitation in EF Core. See https://go.microsoft.com/fwlink/?linkid=2101433 for more detailed information.
After that I discovered from this question that you can't make group by queries evaluated on client anymore.
After more searching I've discovered another solution. So i've re-written my method like this:
private async Task<IEnumerable<MysteryShopper>> FindMysteryShoppers(
SearchMysteryShoppersParameters searchParameters, CancellationToken ct)
{
var lastSearchEdge = _nowProvider.UtcNow().Date.AddDays(-3);
bool shouldHaveDeliveryCheckMark = ShouldHaveDeliveryCheckMark(searchParameters.SearchType);
bool shouldHaveRestaurantCheckMark = ShouldHaveRestaurantCheckMark(searchParameters.SearchType);
bool shouldHaveStandardsCheckMark = ShouldHaveStandardsCheckMark(searchParameters.SearchType);
var lastCheckupEdgeDate = searchParameters.CheckupDates.Max().AddDays(-30);
var mysteryShoppersLeftJoinedWithCheckups = from ms in _ratingsContext.Set<MysteryShopper>()
where ms.MysteryShopperUnits
.Any(u => searchParameters.UnitIds.Contains(u.UnitId)
&& !shouldHaveStandardsCheckMark && ms.StandardsRatingCheck
&& !shouldHaveRestaurantCheckMark && ms.RestaurantCheck
&& !shouldHaveDeliveryCheckMark && ms.DeliveryCheck
&& !ms.IsBanned
&& !ms.IsFraud
&& ms.IsAutoSearchable
&& ms.Suitable
&& !ms.IsRemove
&& ms.SocialNetworkMessagingEnable
&& (ms.LastSearchMessageDateUtc == null || ms.LastSearchMessageDateUtc < lastSearchEdge))
join cc in _ratingsContext.Set<Checkup>()
on ms.Id equals cc.SecretBuyerId into checkups
from cc in checkups.DefaultIfEmpty()
where !_cancelledStates.Contains(cc.State)
select new {MysteryShopper = ms, LastCheckupDate = checkups.Max(c => c.Date)};
var mysteryShoppersLeftJoinedWithCheckupsAndMessages =
from mysteryShopperWithCheckup in mysteryShoppersLeftJoinedWithCheckups
join m in _ratingsContext.Set<Message>()
on mysteryShopperWithCheckup.MysteryShopper.SocialNetworkId equals m.VkUserId into messages
from m in messages.DefaultIfEmpty()
where m.Type == OutgoingMessageType.CandidateSearch && (m.State == OutgoingMessageState.Sending ||
m.State == OutgoingMessageState.Waiting)
select new
{
mysteryShopperWithCheckup.MysteryShopper,
mysteryShopperWithCheckup.LastCheckupDate,
HasPendingMessages = messages.Any()
};
var orderedMysteryShoppersWithoutPendingMessage =
from mysteryShopperWithCheckupAndMessage in mysteryShoppersLeftJoinedWithCheckupsAndMessages
where !mysteryShopperWithCheckupAndMessage.HasPendingMessages &&
mysteryShopperWithCheckupAndMessage.LastCheckupDate < lastCheckupEdgeDate
orderby mysteryShopperWithCheckupAndMessage.LastCheckupDate != null,
mysteryShopperWithCheckupAndMessage.MysteryShopper.LastSearchMessageDateUtc != null,
mysteryShopperWithCheckupAndMessage.MysteryShopper.LastSearchMessageDateUtc
select mysteryShopperWithCheckupAndMessage.MysteryShopper;
return await orderedMysteryShoppersWithoutPendingMessage.ToArrayAsync(ct);
}
But now i get another error:
could not be translated. Either rewrite the query in a form that can be translated, or switch to client evaluation explicitly by inserting a call to either AsEnumerable(), AsAsyncEnumerable(), ToList(), or ToListAsync().
After some more testing i know for sure that checkups.Max(c => c.Date)} and HasPendingMessages = messages.Any() is the source of this error. How to fix this query? You can suggest completely different solution or approach. The main idea is to bring logic from sql to c#.
PS: Sorry for long question.
Added navigation properties and nugget Z.EntityFramework.Plus (for IncludeFilter) and rewritten query like this:
var query = _ratingsContext.SecretBuyers
.AsNoTracking()
.IncludeFilter(ms => ms.Checkups.Where(cc => !_cancelledStates.Contains(cc.State)))
.IncludeFilter(ms => ms.Messages.Where(m => m.Type == OutgoingMessageType.CandidateSearch &&
(m.State == OutgoingMessageState.Sending ||
m.State == OutgoingMessageState.Waiting)))
.Where(ms => !ms.IsBanned
&& !ms.IsFraud
&& ms.IsAutoSearchable
&& ms.Suitable
&& !ms.IsRemove
&& ms.SocialNetworkMessagingEnable
&& (ms.LastSearchMessageDateUtc == null || ms.LastSearchMessageDateUtc < lastSearchEdge)
)
.Where(ms => !shouldHaveDeliveryCheckMark || ms.DeliveryCheck)
.Where(ms => !shouldHaveRestaurantCheckMark || ms.RestaurantCheck)
.Where(ms => !shouldHaveStandardsCheckMark || ms.StandardsRatingCheck)
.Where(ms => ms.MysteryShopperUnits
.Any(u => searchParameters.UnitIds.Contains(u.UnitId))
)
.Where(ms => !ms.Messages.Any())
.Select(x => new {MysteryShopper = x, LastCheckupDate = x.Checkups.Max(c => c.Date)})
.Where(ms => ms.LastCheckupDate < lastCheckupEdgeDate)
.OrderBy(x => x.LastCheckupDate != null)
.ThenBy(x => x.MysteryShopper.LastSearchMessageDateUtc != null)
.ThenBy(x => x.MysteryShopper.LastSearchMessageDateUtc)
.Select(x => x.MysteryShopper)
.Take(searchParameters.MessagesPerUnit);
I'm not sure how to do this since I'm only familiar with the basic form or Linq.
Here are my two sets of code:
var qry = from x in CustomersChecks.CustomersChecksList
where x.RoutingNumber == routingnumber &&
x.BankAccountNumber == bankAccountNumber &&
x.Branch > 0 &&
x.AccountNumber > 0
orderby x.Name
select x;
var qry2 = qry.GroupBy(x => new { x.Branch, x.AccountNumber}).Select(x => x.First()).ToList();
Ultimately, I want to get my first query in order of Branch + Account Number distinctly.
Can they be combined or is what I have the only way to do this?
The quick and dirty solution is just to add the GroupBy chain to the end of the first query.
var qry = (from x in CustomersChecks.CustomersChecksList
where x.RoutingNumber == routingnumber &&
x.BankAccountNumber == bankAccountNumber &&
x.Branch > 0 &&
x.AccountNumber > 0
orderby x.Name
select x).GroupBy(x => new { x.Branch, x.AccountNumber})
.Select(x => x.First())
.ToList();
Or do the following by incorrupating the group by into the exist query syntax
var qry = (from x in CustomersChecks.CustomersChecksList
where x.RoutingNumber == routingnumber &&
x.BankAccountNumber == bankAccountNumber &&
x.Branch > 0 &&
x.AccountNumber > 0
orderby x.Name
group x by new { x.Branch, x.AccountNumber} into grp
select grp.First()).ToList();
var qry = CustomersChecks.CustomersChecksList.Where(x =>
x.RoutingNumber == routingnumber &&
x.BankAccountNumber == bankAccountNumber &&
x.Branch > 0 &&
x.AccountNumber > 0).OrderBy(x => x.Name)
.GroupBy(x => new { x.Branch, x.AccountNumber})
.Select(x => x.First())
.ToList();
I want to be able to pass different variables in a Linq query depending on if a string is null.
string site = null;
int q = a number;
var data = db.tbl_table12345
.Where(site == null
? d => d.stuff_id == org
&& d.Date.Month == q
&& d.Date.Year == year
&& d.Q1 != (int?)null
: d => d.stuff_id == org
&& d.Service == site
&& d.Date.Month == q
&& d.Date.Year == year
&& d.Q1 != (int?)null)
.GroupBy(d => d.Q1)
.Select(d => new
{
q1 = d.Key,
total = d.Count()
});
So in the above example if site == null then we perform a .Where search without the d.Service == site parameter. Else the service parameter is used in addition to the rest of the query. Is this possible?
If you want to add an additional filter to the query when a condition is met then that construct should be outside of the query itself, which LINQ makes quite easy to do:
var query = db.tbl_table12345
.Where(d => d.stuff_id == org
&& d.Date.Month == q
&& d.Date.Year == year
&& d.Q1 != (int?)null);
if (site != null)
query = query.Where(d => d.Service == site);
var data = query.GroupBy(d => d.Q1)
.Select(d => new
{
q1 = d.Key,
total = d.Count()
});
It should work if the ternary operator was "inside" the lambda.
string site = null;
int q = a number;
var data = db.tbl_table12345
.Where(d => site == null
? d.stuff_id == org
&& d.Date.Month == q
&& d.Date.Year == year
&& d.Q1 != (int?)null
: d.stuff_id == org
&& d.Service == site
&& d.Date.Month == q
&& d.Date.Year == year
&& d.Q1 != (int?)null)
.GroupBy(d => d.Q1)
.Select(d => new
{
q1 = d.Key,
total = d.Count()
});
Breaking up the expressions will let you visualize your logic better.
string site = null;
int month = a number;
Expression<Func<SomeType, bool>> nullExpression =
d => d.stuff_id == org
&& SqlFunctions.DatePart("MONTH", d.Date) == month
&& SqlFunctions.DatePart("YEAR", d.Date) == year
&& d.Q1 != (int?)null;
Expression<Func<SomeType, bool>> notNullExpression =
d => d.stuff_id == org
&& SqlFunctions.DatePart("MONTH", d.Date) == month
&& SqlFunctions.DatePart("YEAR", d.Date) == year
&& d.Q1 != (int?)null
&& d.Service == site;
var expression = site == null ? nullExpression : notNullExpression
var data = db.tbl_table12345
.Where(expression)
.GroupBy(d => d.Q1)
.Select(d => new { q1 = d.Key, total = d.Count() });
Or using Expression trees:
var expression = BuildWhere(org, month, year, site);
var data = db.tbl_table12345
.Where(expression)
.GroupBy(d => d.Q1)
.Select(d => new { q1 = d.Key, total = d.Count() });
And here is a method that will build up your where Expression<Func<SomeType, bool>.
public Expression BuildWhere(int org, int month, int year, string service = null)
{
var datePartMethod =
typeof(SqlFunctions)
.GetMethod("DatePart",
new[]
{
typeof(string),
typeof(DateTime?)
});
// Variable d
var variable =
Expression.Variable(typeof(SomeType));
var orgConstant =
Expression.Constant(org);
// d.stuff_id
var stuffId =
Expression.Property(variable, "stuff_id");
// d.stuff_id == org
var stuffIdEquals =
Expression.Equal(stuffId, orgConstant);
// d.Date cast into Nullable DateTime
var date =
Expression.Convert(
Expression.Property(variable, "Date"),
typeof(DateTime?));
var monthPartConstant =
Expression.Constant("MONTH");
// month cast to nullable int
var monthConstant =
Expression.Convert(
Expression.Constant(month),
typeof(int?));
var yearPartConstant =
Expression.Constant("YEAR");
// year cast to nullable int
var yearConstant =
Expression.Convert(
Expression.Constant(year),
typeof(int?));
// SqlFunctions.DatePart("MONTH", d.Date)
var invokeDatePartMonthPart =
Expression.Call(
datePartMethod,
monthPartConstant,
date);
// SqlFunctions.DatePart("YEAR", d.Date)
var invokeDatePartYearPart =
Expression.Call(
datePartMethod,
yearPartConstant,
date);
// SqlFunctions.DatePart("MONTH", d.Date) == month
var dateMonthEquals =
Expression.Equal(
invokeDatePartMonthPart,
monthConstant);
// SqlFunctions.DatePart("MONTH", d.Date) == year
var dateYearEquals =
Expression.Equal(
invokeDatePartYearPart,
yearConstant);
// d.Q1
var q1 = Expression.Property(variable, "Q1");
var nullConstant =
Expression.Constant((int?) null);
// d.Q1 != (int?) null
var q1NotEquals =
Expression.NotEqual(
q1,
nullConstant);
// d.stuff_id == org
// && SqlFunctions.DatePart("MONTH", d.Date) == month
// && SqlFunctions.DatePart("YEAR", d.Date) == year
// && d.Q1 != (int?) null
var andExpression =
Expression.AndAlso(stuffIdEquals,
Expression.AndAlso(dateMonthEquals,
Expression.AndAlso(dateYearEquals,
q1NotEquals)));
// Add d.Service only when not null
if(service != null)
{
// d.Service
var serviceConstant =
Expression.Constant(service);
var serviceProperty =
Expression.Property(
variable,
"Service");
// d.Service == service
var serviceEquals =
Expression.Equal(
serviceProperty,
serviceConstant);
andExpression =
Expression.AndAlso(
andExpression,
serviceEquals);
}
// Creates a lambda to represent the logic
var parameter = Expression.Parameter(typeof(SomeType));
return Expression
.Lambda<Func<SomeType, bool>>(
andExpression,
parameter);
}
From the way your code looks, it appears to me that you're using Entity Framework for your query. If so, you aren't allowed things like d.Date.Month, since EF doesn't know how to properly translate that into SQL by itself. You need to use the SqlFunctions class (specifically the DatePart method) in order to get this query working. Using #Servy's solution as a start:
var query = db.tbl_table12345
.Where(d => d.stuff_id == org
&& SqlFunctions.DatePart("MONTH", d.Date) == q
&& SqlFunctions.DatePart("YEAR", d.Date) == year
&& d.Q1 != (int?)null);
if (site != null)
query = query.Where(d => d.Service == site);
var data = query.GroupBy(d => d.Q1)
.Select(d => new
{
q1 = d.Key,
total = d.Count()
});
Another good reason to use this approach is that all of the LINQ clauses above (Where, GroupBy, and Select) all employ deferred execution (see here for a list of deferred vs. immediate executed methods), which means that only one query will be sent to your database for the final data, and only when you actually use that variable in some way.
Your syntax is wrong
.Where(d => site == null
? d.stuff_id == org
&& d.Date.Month == q && d.Date.Year == year
&& d.Q1 != (int?)null
: d.stuff_id == org
&& d.Service == site && d.Date.Month == q
&& d.Date.Year == year && d.Q1 != (int?)null)
I have this function in a class:
public IEnumerable<PedidosList> Pedidos_Listar(string sComprobante, Clientes MyCliente = null, DateTime? dDesde = null, DateTime? dHasta = null, bool bCumplidos = false)
{
using (var context = new OhmioEntities())
{
IEnumerable<PedidosList> query =
from Pedidos in context.Pedidos
join Clientes in context.Clientes on Pedidos.ID_Cliente equals Clientes.ID_Cliente
where Pedidos.ID_Comprobante == sComprobante
select new PedidosList {ID_Pedido = Pedidos.ID_Pedido, Fecha=Pedidos.Fecha, Aprobado=Pedidos.Aprobado, Bruto=Pedidos.Bruto, Cliente=Clientes.RazonFantasia,
FechaEntrega=Pedidos.FechaEntrega, Neto=Pedidos.Neto, Numero=Pedidos.Numero, Observaciones=Pedidos.Observaciones, Entregado=Pedidos.Entregado, ID_Cliente=Pedidos.ID_Cliente };
if (MyCliente != null) query = query.Where(i => i.ID_Cliente == MyCliente.ID_Cliente);
if (MyCliente != null) query = query.Where(i => i.ID_Cliente == MyCliente.ID_Cliente);
if (dDesde != null && dHasta != null) query = query.Where(i => i.Fecha >= dDesde && i.Fecha <= dHasta);
if (bCumplidos == false) query = query.Where(i => i.Entregado == false);
return query.ToList();
}
}
The idea is to use LINQ projection to fill a custom class object where multiple optional filter parameters are evaluated. My question is: For performance and encapsulation reasons, can I make the projection AFTER optional where filters are applied? In my code the projection is done BEFORE, so i can only filter by the fields on my custom class, but i want to filter over the original class fields. Thank you.
var query =
from Pedidos in context.Pedidos
join Clientes in context.Clientes on Pedidos.ID_Cliente equals Clientes.ID_Cliente
where Pedidos.ID_Comprobante == sComprobante
select new { Pedidos, Clientes };
if (MyCliente != null)
{
query = query.Where(i => i.Pedidos.ID_Cliente == MyCliente.ID_Cliente);
query = query.Where(i => i.Periodos.ID_Cliente == MyCliente.ID_Cliente);
}
if (dDesde != null && dHasta != null)
query = query.Where(i => i.Pedidos.Fecha >= dDesde && i.Pedidos.Fecha <= dHasta);
if (bCumplidos == false)
query = query.Where(i => i.Pedidos.Entregado == false);
return (from x in query
let Pedidos = x.Pedidos
let Clientes = x.Clientes
select new PedidosList {ID_Pedido = Pedidos.ID_Pedido, Fecha=Pedidos.Fecha, Aprobado=Pedidos.Aprobado, Bruto=Pedidos.Bruto, Cliente=Clientes.RazonFantasia, FechaEntrega=Pedidos.FechaEntrega, Neto=Pedidos.Neto, Numero=Pedidos.Numero, Observaciones=Pedidos.Observaciones, Entregado=Pedidos.Entregado, ID_Cliente=Pedidos.ID_Cliente
}).ToList();