How can I get a single row result (e.g. in form of a table/array) back from a sql statement. Using Lua Sqlite (LuaSQLite3). For example this one:
SELECT * FROM sqlite_master WHERE name ='myTable';
So far I note:
using "nrows"/"rows" it gives an iterator back
using "exec" it doesn't seem to give a result back(?)
Specific questions are then:
Q1 - How to get a single row (say first row) result back?
Q2 - How to get row count? (e.g. num_rows_returned = db:XXXX(sql))
In order to get a single row use the db:first_row method. Like so.
row = db:first_row("SELECT `id` FROM `table`")
print(row.id)
In order to get the row count use the SQL COUNT statement. Like so.
row = db:first_row("SELECT COUNT(`id`) AS count FROM `table`")
print(row.count)
EDIT: Ah, sorry for that. Here are some methods that should work.
You can also use db:nrows. Like so.
rows = db:nrows("SELECT `id` FROM `table`")
row = rows[1]
print(row.id)
We can also modify this to get the number of rows.
rows = db:nrows("SELECT COUNT(`id`) AS count FROM `table`")
row = rows[1]
print(row.count)
Here is a demo of getting the returned count:
> require "lsqlite3"
> db = sqlite3.open":memory:"
> db:exec "create table foo (x,y,z);"
> for x in db:urows "select count(*) from foo" do print(x) end
0
> db:exec "insert into foo values (10,11,12);"
> for x in db:urows "select count(*) from foo" do print(x) end
1
>
Just loop over the iterator you get back from the rows or whichever function you use. Except you put a break at the end, so you only iterate once.
Getting the count is all about using SQL. You compute it with the SELECT statement:
SELECT count(*) FROM ...
This will return one row containing a single value: the number of rows in the query.
This is similar to what I'm using in my project and works well for me.
local query = "SELECT content FROM playerData WHERE name = 'myTable' LIMIT 1"
local queryResultTable = {}
local queryFunction = function(userData, numberOfColumns, columnValues, columnTitles)
for i = 1, numberOfColumns do
queryResultTable[columnTitles[i]] = columnValues[i]
end
end
db:exec(query, queryFunction)
for k,v in pairs(queryResultTable) do
print(k,v)
end
You can even concatenate values into the query to place inside a generic method/function.
local query = "SELECT * FROM ZQuestionTable WHERE ConceptNumber = "..conceptNumber.." AND QuestionNumber = "..questionNumber.." LIMIT 1"
Okay guys. I'm a noob. I know (some) programming, a little SQL, and scant LINQ to SQL.
GOAL: Bind nested ListViews to LINQ generated iQueryable of anonymous type. I want to use LINQ because you can use GroupBy and bind the nested ListView to the 'it' keyword.
SETUP: I have groups of sets of conditions. Each set of conditions is stored in the BillingCodes table. Each group of BillingCodes is stored in the BillingGroups table.
I have a custom object that stores the ID, Name, and NumCodes for each BillingGroup that the user has chosen.
I have a collection of these objects called GroupsList that has a list of the groups that the user has chosen.
Problem 1: I can iterate through GroupsList and grab all the IDs. How do I translate the SQL 'WHERE ID IN(a string of comma delineated IDs)' for LINQ to SQL? Is that the best way to do that?
Problem 2: Once I have the list of BillingGroups I need to iterate through each group. For each group, I need to iterate through the BillingCodes. For each BillingCode I need to generate a WHERE clause that has all of the conditions in the BillingCode. I propose something like so:
for each BillingGroup in BillingGroups
for each BillingCode in BillingGroup.BillingCodes
where1 = "..."
next
next
Problem 3: Here's the part where I don't have a clue. I need to dynamically create a query in LINQ to SQL. Keep in mind that I don't know how many groups there'll be or how many codes are in each group.
There are 2 tables:
**transactions**
transaction_id
patient_id
svc_date
code
charge
description
**v_patients**
first_name
last_name
patient_id
date_of_birth
insname
active
provider_name
I imagine a query that looks something like this:
[Group1] Select MAX(svc_date), patient_id, transaction_id
From (
Select transaction_id, patient_id, svc_date
From transactions join v_patients on patient_id
[Code1] Where code=”” and description contains “” and insurance contains “” and charge >= PriceFloor and charge <= PriceCeiling
UNION
Select transaction_id, patient_id, svc_date
From transactions join v_patients on patient_id
[Code2]Where code=”” and description contains “” and insurance contains “” and charge >= PriceFloor and charge <= PriceCeiling
)
Group By patient_id
UNION
[Group2] Select MAX(svc_date), patient_id, transaction_id
From (
Select transaction_id, patient_id, svc_date
From transactions join v_patients on patient_id
[Code1]Where code=”” and description contains “” and insurance contains “” and charge >= PriceFloor and charge <= PriceCeiling
UNION
Select transaction_id, patient_id, svc_date
From transactions join v_patients on patient_id
[Code2]Where code=”” and description contains “” and insurance contains “” and charge >= PriceFloor and charge <= PriceCeiling
)
Group By patient_id
Problem 4: Lastly, I want to wrap that query in one that groups by patient_id. Something that end in Select as New With {key, it as transactions, num as count()}
I have pieced together this knowledge with endless reading and searches. I'll continue to look for answers, but any help would be GREATLY appreciated.
Thanks.
EDIT - ANSWER:
Here's the code that ended up working for me:
Dim chosenIDs() As Short = (From p In GroupsList _
Select p.ID).ToArray()
GroupMatchListView.DataSource = Nothing
If chosenIDs.Length > 0 Then
Dim db As New AudioRxInternalDataContext
Dim vf As New VersaformDataContext
Dim chosenGroups() As BillingGroup = (db.BillingGroups.Where(Function(m) chosenIDs.Contains(m.ID))).ToArray()
Dim wholeResults As List(Of transaction) = Nothing
For Each chosenGroup As BillingGroup In chosenGroups
Dim groupResults As List(Of transaction) = Nothing
For Each chosenCode As BillingCode In chosenGroup.BillingCodes
Dim codePredicate = PredicateBuilder.True(Of transaction)()
codePredicate = codePredicate.And(Function(i) i.code.Equals(chosenCode.Code))
If Not chosenCode.Description Is Nothing Then codePredicate = codePredicate.And(Function(i) i.description.ToUpper().Contains(chosenCode.Description.ToUpper()))
If Not chosenCode.Insurance Is Nothing Then codePredicate = codePredicate.And(Function(i) i.v_patient.insname.ToUpper().Contains(chosenCode.Insurance.ToUpper()))
If Not chosenCode.PriceFloor Is Nothing Then codePredicate = codePredicate.And(Function(i) i.charge >= chosenCode.PriceFloor)
If Not chosenCode.PriceCeiling Is Nothing Then codePredicate = codePredicate.And(Function(i) i.charge <= chosenCode.PriceCeiling)
If groupResults Is Nothing Then
groupResults = vf.transactions.Where(codePredicate).ToList()
Else
groupResults.AddRange(vf.transactions.Where(codePredicate).ToList())
End If
Next
groupResults = groupResults.GroupBy(Function(r) r.patient_id).SelectMany(Function(g) g.Where(Function(r) r.svc_date = g.Max(Function(a) a.svc_date))).ToList()
If wholeResults Is Nothing Then
wholeResults = groupResults
Else
wholeResults.AddRange(groupResults)
End If
Next
Dim conditionsPredicate = PredicateBuilder.True(Of transaction)()
conditionsPredicate = conditionsPredicate.And(Function(i) i.v_patient.active = "Y")
conditionsPredicate = conditionsPredicate.And(Function(i) i.svc_date >= StartDateBox.Text)
conditionsPredicate = conditionsPredicate.And(Function(i) i.svc_date <= EndDateBox.Text)
If Not OfficeDropDownList.SelectedValue = "Both" Then conditionsPredicate = conditionsPredicate.And( _
Function(i) (If(i.v_patient.provider_name, "").ToUpper().Contains(OfficeDropDownList.SelectedValue.ToUpper())))
wholeResults = wholeResults.Where(conditionsPredicate.Compile()).ToList()
Dim goliath = From f In wholeResults _
Group f By f.v_patient Into Group _
Order By v_patient.last_name, v_patient.first_name, v_patient.date_of_birth _
Select New With {.PatientID = v_patient.patient_id, .LastName = v_patient.last_name, .FirstName = v_patient.first_name, _
.DOB = v_patient.date_of_birth, .Ins = v_patient.insname, .MatchCount = Group.Count(), .Matches = Group}
GroupMatchListView.DataSource = goliath
theMatchesLabel.Text = goliath.Count()
Else
theMatchesLabel.Text = "0"
End If
Don't ask me why I used goliath for the final variable. I created that bit of code late at night, and the previous attempt had been named david.
Thanks for everyone's suggestions!
EDIT : Shame on me : I didn't use VB, but c#. But I hope some answers should help a bit...
Problem 1 : grab a list or array of int (or string) named Ids, for example and use
.Where(m => Ids.Contains(m.Id)
If the list of Ids comes from Database, I think you have to make 2 queries...
Problem 2 : not really clear with the infos you give, but the use of
SelectMany(x => blabla)
somewhere should do the trick (but once again hard to say like so)
Problem 3 : here also not really clear : what's the interest of you union in same groups ? If the difference are only codes, why not use the system of Problem 1 ?
To build "dynamic queries", I can just say that IQueryable can be build "on demand", like classic code, for example
var query = blabla;
if (searchCriterion.Name != null)
query = query.Where(m => m.Name == searchCriterion.Name);
Problem 4 : I use a "ToDictionary()" extension, as you seem to need a KeyValuePair, but they are of course other ways.
GroupBy(m => m.TransactionId).ToDictionary(m => m.Key, m => m.Count)
But... if you could be a little bit more concrete, maybe ;)
Edit Problem 4 :
didn't read well, rather something like that
GroupBy(m => m.TransactionId).Select(g => new {
patientId = g.Key,
transaction = g.SelectMany(p => p.Transactions),
num = g.Count());
I'm having issues with a rather complex Linq query and I need some advice. This involves VB syntax so I need specific answers for that platform, as I have a lot of trouble translating the C# syntax to VB at times.
I have to join two main tables, and I need to filter the results by elements in an ASP.NET web form. These filters are created on the fly so I have to use a lot of where extensions to filter the query. I want to execute the query with as optimized SQL as possible.
I am first doing a simple join between TW_Sites and TW_Investigators. Then there are two sub-tables that are involved. TW_InvestigatorToArea and TW_InvestigatorToDisease. While most of the where clauses are working fine, I have found a performance issue that won't be an issue right now, but will be an issue as the table gets bigger.
The arrays DiseaseCategories and DiseaseAreas would be the results of a CheckBoxList result.
Protected Sub LoadResults()
' Get Dictionary of Filters
Dim FilterDictionary As OrderedDictionary = Session.Item("InvestigatorFilterDictionary")
' Initialize LinqToSql
Dim LinqDbHandler As TrialWatchDC = New TrialWatchDC(WebConfigurationManager.ConnectionStrings("DataSourceName").ConnectionString)
' Create List of Categories to Filter By
Dim DiseaseCategories() As Integer = {1, 2, 3, 4, 5, 6, 11, 22, 361, 77, 82, 99, 400}
Dim CategorySubQuery = From ic In LinqDbHandler.TW_InvestigatorsToDiseases Where DiseaseCategories.Contains(ic.DiseaseCategoryID) Select ic.InvestigatorID Distinct
' Dim CategorySubArray = CategorySubQuery.ToArray()
' Create List of Areas to Filter By
Dim AreaCategories() As Integer = {17, 1, 3, 5}
Dim AreaSubQuery = From ic In LinqDbHandler.TW_InvestigatorsToAreas Where AreaCategories.Contains(ic.AreaID) Select ic.InvestigatorID Distinct
Dim AreaSubArray = AreaSubQuery.ToArray()
Dim dc As DbCommand
Dim ThisQuery = From Site In LinqDbHandler.TW_Sites _
Join Investigator In LinqDbHandler.TW_Investigators On Site.TrialSiteID Equals Investigator.TrialSiteID _
Join SiteType In LinqDbHandler.TW_SiteTypes On Site.SiteTypeID Equals SiteType.SiteTypeID _
Order By Site.ResearchCenterName, Investigator.InvestigatorName
Select New With {.TrialSiteID = Site.TrialSiteID, _
.InvestigatorID = Investigator.InvestigatorID, _
.ResearchCenterName = Site.ResearchCenterName, _
.SiteTypeID = SiteType.SiteTypeID, _
.TypeLabel = SiteType.TypeLabel, _
.CenterState = Site.CenterState, _
.CenterCountry = Site.CenterCountry, _
.ContactName = Site.ContactName, _
.ContactEMail = Site.ContactEMail, _
.ContactPhone = Site.ContactPhone, _
.IsRcppSubscriber = Site.IsRcppSubscriber, _
.InvestigatorName = Investigator.InvestigatorName, _
.IsPublicationSubscriber = Investigator.IsPublicationSubscriber, _
.HasPhase01 = Investigator.HasPhase01, _
.HasPhase02 = Investigator.HasPhase02, _
.HasPhase03 = Investigator.HasPhase03, _
.HasPhase04 = Investigator.HasPhase04, _
.AreaList = String.Join(",", (From ia In LinqDbHandler.TW_InvestigatorsToAreas Join a In LinqDbHandler.Disease_Areas On ia.AreaID Equals a.Area_Number Where ia.InvestigatorID = Investigator.InvestigatorID Order By a.Area_Name Select a.Area_Name Distinct).ToArray()), _
.CategoryList = String.Join(",", (From id In LinqDbHandler.TW_InvestigatorsToDiseases Join d In LinqDbHandler.Disease_Categories On id.DiseaseCategoryID Equals d.Category_Number Where id.InvestigatorID = Investigator.InvestigatorID Order By d.Category_Name Select d.Category_Name Distinct).ToArray())}
If Not String.IsNullOrEmpty(FilterDictionary.Item("CountryFilter")) Then
ThisQuery = ThisQuery.Where(Function(s) s.CenterCountry = FilterDictionary.Item("CountryFilter").ToString())
End If
If Not String.IsNullOrEmpty(FilterDictionary.Item("SiteType")) Then
ThisQuery = ThisQuery.Where(Function(s) s.SiteTypeID = Convert.ToInt32(FilterDictionary.Item("SiteType")))
End If
dc = LinqDbHandler.GetCommand(ThisQuery)
If Not String.IsNullOrEmpty(FilterDictionary.Item("StateFilter")) Then
ThisQuery = ThisQuery.Where(Function(s) s.CenterState = FilterDictionary.Item("StateFilter").ToString())
End If
dc = LinqDbHandler.GetCommand(ThisQuery)
ThisQuery = ThisQuery.Where(Function(i) CategorySubArray.Contains(i.InvestigatorID))
ThisQuery = ThisQuery.Where(Function(i) AreaSubArray.Contains(i.InvestigatorID))
dc = LinqDbHandler.GetCommand(ThisQuery)
Trace.Warn("Command", dc.CommandText)
For Each dcp As SqlParameter In dc.Parameters
Trace.Warn(dcp.ParameterName.ToString(), dcp.Value.ToString())
Next
Dim ThisLinqResult = ThisQuery
InvestigatorResultGrid.DataSource = ThisLinqResult
InvestigatorResultGrid.DataBind()
End Sub
The big problem is, when you look at the code, basically I am first converting the filtered subqueries into an array and then passing it into the SQL code. The result ends up making an SQL Query with a lot of parameters, as seen below.
SELECT [t0].[TrialSiteID], [t1].[InvestigatorID], [t0].[ResearchCenterName], [t2].[SiteTypeID], [t2].[TypeLabel], [t0].[CenterState], [t0].[CenterCountry], [t0].[ContactName],
[t0].[ContactEMail], [t0].[ContactPhone], [t0].[IsRcppSubscriber], [t1].[InvestigatorName], [t1].[IsPublicationSubscriber], [t1].[HasPhase01], [t1].[HasPhase02], [t1].[HasPhase03],
[t1].[HasPhase04]
FROM [dbo].[TW_Sites] AS [t0]
INNER JOIN [dbo].[TW_Investigators] AS [t1] ON [t0].[TrialSiteID] = [t1].[TrialSiteID]
INNER JOIN [dbo].[TW_SiteTypes] AS [t2] ON [t0].[SiteTypeID] = ([t2].[SiteTypeID])
WHERE ([t1].[InvestigatorID] IN (#p0, #p1, #p2, #p3, #p4, #p5, #p6, #p7, #p8, #p9, #p10, #p11, #p12, #p13, #p14, #p15, #p16, #p17, #p18, #p19, #p20, #p21, #p22, #p23, #p24, #p25, #p26, #p27,
#p28, #p29, #p30, #p31, #p32, #p33, #p34, #p35, #p36, #p37, #p38, #p39, #p40, #p41, #p42, #p43, #p44, #p45, #p46, #p47, #p48, #p49, #p50, #p51, #p52, #p53, #p54, #p55, #p56, #p57, #p58,
#p59, #p60, #p61, #p62, #p63, #p64, #p65, #p66, #p67, #p68, #p69, #p70, #p71, #p72, #p73, #p74, #p75, #p76, #p77, #p78, #p79, #p80, #p81, #p82, #p83, #p84, #p85, #p86, #p87, #p88, #p89,
#p90, #p91, #p92, #p93, #p94, #p95, #p96, #p97, #p98, #p99, #p100, #p101, #p102, #p103, #p104, #p105, #p106, #p107, #p108, #p109, #p110, #p111, #p112, #p113, #p114, #p115)) AND
([t1].[InvestigatorID] IN (#p116, #p117, #p118, #p119, #p120, #p121, #p122, #p123, #p124, #p125, #p126, #p127, #p128, #p129, #p130, #p131, #p132, #p133, #p134, #p135, #p136, #p137, #p138,
#p139, #p140, #p141, #p142, #p143, #p144, #p145, #p146, #p147, #p148, #p149, #p150, #p151, #p152, #p153, #p154, #p155, #p156, #p157, #p158, #p159, #p160, #p161, #p162, #p163, #p164, #p165,
#p166, #p167, #p168, #p169, #p170, #p171, #p172, #p173, #p174, #p175, #p176, #p177, #p178, #p179, #p180, #p181, #p182, #p183, #p184, #p185, #p186, #p187, #p188, #p189, #p190, #p191, #p192,
#p193, #p194, #p195, #p196, #p197, #p198, #p199, #p200, #p201, #p202, #p203, #p204, #p205))
ORDER BY [t0].[ResearchCenterName], [t1].[InvestigatorName]
This is a lot of parameters and will just get worse. Basically, instead of having a small IN clause with the conditions, I have a much larger IN clause with the investigator ids.
So, what I am trying to do is figure out how to, instead of converting the Area and Category queries into an array and then appending them to the third query, to get the queries to include the sub-tables and directly search for the matching ids of the areas and categories. I need to be able to use the predicate syntax since areas and categories are two sub-tables, and sometimes both or neither will be included. I know it has to do with either the .Any(), .Join(), or .Where() predicates, I just don't know how to get it to work.
Basically, I'm trying to change the SQL to make it look more like this.
WHERE ([t1].[InvestigatorID] IN (SELECT InvestigatorID FROM TW_InvestigatorsToAreas
WHERE DiseaseCategoryID IN (#p101, #p102, #p103)))
Any help or guidance would be appreciated.
Is this LINQ to SQL or EF?
Most ORMs will generate dynamic SQL with each ID for the IN statement as a parameter. Some smarter ones will create a temp table and join against that instead or use a nested subquery (or if you're really creative you might extend an ORM to do this).
I know DataObjects .NET does the temp table thing and LLBLGen can use nested subqueries for joins (aka prefetch pathes) and I'm sure there are at least a couple of others that do too.
One thing to note: Your mileage may vary. One big plus with a temp table is that you get around the 2400 parameter limit in SQL Server (though I'm not sure if that's an issue for you...). However, certain, maybe 1 in 20 queries will actually perform much much slower joining against a temp table (even an indexed one) vs. just passing in each ID as a parameter. Still, in general though, you'll have much better performance because the execution plan doesn't need to get re-compiled for each query.
It looks like it just came down to a syntax statement. I guess you just have to invoke the subquery from the LinqToSql object itself.
If DCHash.Count > 0 Then
ThisQuery = ThisQuery.Where(Function(i) (From ic In LinqDbHandler.TW_InvestigatorsToDiseases Where DiseaseCategories.Contains(ic.DiseaseCategoryID) Select ic.InvestigatorID).Contains(i.InvestigatorID))
End If
If AreaHash.Count > 0 Then
ThisQuery = ThisQuery.Where(Function(i) (From ia In LinqDbHandler.TW_InvestigatorsToAreas Where DiseaseAreas.Contains(ia.AreaID) Select ia.InvestigatorID).Contains(i.InvestigatorID))
End If