How can I search using 3 fields on vb.net
Usually we use something like:
Dim query As String = "Insert into () values () Where id=1"
I am not really good in access or sql, so I asked.
week, sow order and piglet# are different fields, because I need to segregate in the future if the user searches only on weeks.
What I want is, get the data which is the same as what the user inputs and display it in the DGV. Is something like this possible:
Dim query As String = "Insert into (FarrowDate) values (dtpFarrow.Text) Where week=1,soworder=1,pigletnumber=0"
' display the data in the DGV '
Help please, they only gave me a 2 week deadline >.<
In your query you cannot use where in insert statement.Use update statement
Update tablename set FarrowDate='' where PigletNumber='0' And Week='1' And SowOrder='1'
Related
I'm trying to retrieve the values from an existing query and assign variable to it using VBA (Access 2016), to be able to use it in the further code.
And I'm totally stuck in that step, a very simple one, but I'm a newbie in VBA.
I have a query, which in SQL looks like that:
SELECT Max(CatalogConditions.DefConditionID) AS MaxDefConditionID, Max(ImplantCondition.InteractionID) AS MaxImplantCondition_InterationID, Max(Results_Epilepsy_BSL.ResultEpilepsyBSL_ID) AS MaxBSLresultsID, Max(Results_Epilepsy_Post.ResultEpilepsyPost_ID) AS MaxPOSTresultsID
FROM ((CatalogConditions INNER JOIN ImplantCondition ON CatalogConditions.DefConditionID = ImplantCondition.DefConditionID) INNER JOIN Results_Epilepsy_BSL ON ImplantCondition.InteractionID = Results_Epilepsy_BSL.InteractionID) INNER JOIN Results_Epilepsy_Post ON ImplantCondition.InteractionID = Results_Epilepsy_Post.InteractionID;
So, I'd like to assign all these Max... IDs to variables in my code, which I'm going to use later.
If anyone could help me, it would be great. Thx
You open a recordset, and then read the values from its fields.
Dim rst As DAO.Recordset
Dim DefConditionID As Long
Dim InteractionID As Long
' ...
Set rst = CurrentDb.OpenRecordset("myQuery")
' Read values into variables
DefConditionID = rst!MaxDefConditionID
InteractionID = rst!MaxImplantCondition_InterationID
' ...
rst.Close
Note that this reads the values from the first record of the query, so this assumes that the query only returns a single record.
To read one single value from a query or table, you can also use the DLookup function.
I have an MS Access db. I am writing an application in C# to access it. I have a field "FileName" of type "Short Text in MS Access. Data in FileName field is like "Test 11-12-2004 15.11.15".
Using a Date Range, I got to search records based on FileName field. I am not able to get - How do I compare the date of this format and retrieve the records ? FileName is a Text type and date is a substring of it. Retrieving only the date part and comparing with >= beginDate && <= endDate seems like a puzzle to me.
Can anyone suggest how do I write SQL query to perform this date range comparision and retrieve those records - "Select * from TestHead where FileName......" ????
Any help is appreciated.
Thanks a lot,
In your C# code, as you are going through the records, I'd split the string like this:
char[] delimiters = {' '};
string[] FileNameParts = FileName.Split(delimiters);
This will result in an array FileNameParts, the second element of which will contain the date, which you can convert to an actual date for use in the query:
DateTime FileNameDate = Convert.ToDateTime(FileNameParts(1))
Something along the lines of:
sSQL = "SELECT * FROM Table WHERE " & beginDate & " <= " & FileNameDate
I see this as preferable to adding a column to your table that contains the date substring of the FileName field, because then you constantly need to be updating that column whenever existing records are modified or new records are added. That means more clutter on the C# side, or an UPDATE query on the Access side which at least needs to get called periodically. Either way it would be more communication with the database.
I have a question concerning a "serie of queries". After searching the internet for hours, I am really lost!
I want to make 200 queries with changing criteria (the values from the field "City"). How can I tell Access "please repeat the query on the fields "X", "Y" and "Z" by grouping by the field "City". Is there a simple way to make Access pull the Values of "City" from a list and creating a query having the same name like the Value in "City". And doing that for all 200 Cities?
Unfortunately, I am fairly new to Access and VBA. Any help would be HIGHLY APPRECIATED :)
Thanks in advance
A few options. You could open a recordset containing all your Cities, then loop through it and you get a buncha queries:
dim s as string
dim sql as string
dim r as new adodb.recordset
'populate r with SELECT * FROM tblCities (code not shown here)
s = r![City]
sql = "SELECT * FROM tbl1 WHERE City = '" & s & "';"
debug.print sql
'do whatever you want with the contents of sql
I have a Data Access Layer class that has a method (GetPeople) that will retrieve records from a SQL Server table (people). This table has more than 20 fields, including varbinary type.
Right now, SQL query is something like
SELECT * FROM people
From my BLL class, I will call DAL.GetPeople(), which will return all columns.
What would be the best way to specify which columns to return, so I could improve performance? For example, sometimes I would like to return all fields, other times, just one or two.
UPDATE
To explain it better:
In DAL I have a method GetPeople() which calls a SQL Server function GetPeople.
In BLL I have a method GetPeople() which calls DAL.GetPeople(), after doing some business logic.
In my presentation layer, I call BLL.GetPeople().
This is working, but on SQL function, I have "SELECT * FROM people". Sometimes I would like to retrieve only one column (eg. name) from table, but in this case all columns are returned, which I think is affects performance.
So, I would like to have a kind of dynamic SELECT query on this SQL Server function, whose columns returned would depend on how I call the function...
I think you are after something like this where you can pass in a comma-seperated list of column names
Private Function GenerateQuery(ByVal columnNames As String) As String
' columnNames in the following format 'column1,column2,column3'
Dim lstColumnNames As String() = Split(columnNames, ",")
Dim strSQL As New StringBuilder
strSQL.Append("SELECT ")
For intColNumber As Integer = 0 To lstColumnNames.GetUpperBound(0)
strSQL.Append("[")
strSQL.Append(lstColumnNames(intColNumber))
strSQL.Append("]")
If intColNumber < lstColumnNames.GetUpperBound(0) Then
strSQL.Append(", ")
End If
Next
strSQL.Append(" FROM People ")
Return strSQL.ToString
End Function
You can use it like this: SqlCommand.CommandText = GenerateQuery("column1,column2,column3")
The column names are wrapped in [] symbols so you don't have to worry about reserved words causing the database to error.
Change your SQL-query to something like
SELECT column1, column2, column3 FROM people;
EDIT:
What you are going to need to do is create function that will put your SQL string together for you. When i did this before, I had all of the available fields in a checked-list control, and if i wanted them pulled, I checked them. The checked items were then put through the function to assemble the string. It should be pretty simple since there are not any joins going on.
I've got a tablea such as below, I know its bad design having multifield value column but I'm really looking for a hack right now.
Student | Age | Classes
--------|------|----------
foo | 23 | classone, classtwo, classthree, classfour
bar | 24 | classtwo, classfive, classeight
When I run a simple select query as below, I want the results such a way that even occurrence of classtwo is displayed as class2
select student, classes from tablea;
I tried the replace() function but it doesnt work on multivalued fields >_<
You are in a tough situation and I can't think of a SQL solution for you. I think your best option would be to write a VB function that will take the string of data, parse it out (replacing) the returning you the updated string that you can update your data with.
I can cook up quite a few ways to solve this.
You can explode the mv by using Classes.Value in your query. This will cause one row to appear for each value in the query and thus you now can use replace on that. However, this will result in one separate row for each class.
So use this:
Select student, classes.Value from tablea
Or, for this example:
Select student, replace(classes.Value,"classtwo","class2") as myclass
from tablea
If you want one line, AND ALSO the multi value classes are NOT from another table (else they will be returning ID not text), then then you can use the following trick
Select student, dlookup("Classes","tablea","id = " & [id]) as sclasses
from tablea
The above will return the classes separated by a space as a string if you use dlookup(). So just add replace to the above SQL. I suppose if you want, you could also do replace on the space back to a "," for display.
Last but not least, if this those classes are coming from another table, then the dlookup() idea above will not work. So just simply create a VBA function.
You query becomes:
Select student, strClass([id]) as sclasses from tablea
And in a standard code module you create a public function like this:
Public Function strClass(id As Variant) As String
Dim rst As DAO.Recordset
If IsNull(id) = False Then
Set rst = CurrentDb.OpenRecordset("select Classes.Value from tableA where id = " & id)
Do While rst.EOF = False
If strClass <> "" Then strClass = strClass & ","
strClass = strClass & Replace(rst(0), "classtwo", "class2")
rst.MoveNext
Loop
rst.Close
Set rst = Nothing
End If
End Function
Also, if you sending this out to a report, then you can DUMP ALL of the above ideas, and simply bind the above to a text box on the report and put the ONE replace command around that in the text box control. It is quite likely you going to send this out to a report, but you did ask how to do this in a query, and it might be the wrong question since you can "fix" this issue in the report writer and not modify the data at the query level. I also think the replace() command used in the report writer would likely perform the best. However, the above query can be exported, so it really depends on the final goal here.
So lots of easy ways to do this.