Get results from two tables - asp.net/SQL Server 2008R2 - asp.net

Question

I have a search form with 2 fields(first name and last name) from one table (Just has person's information) and 4 (Incident number, date, place, created by) from the other (has one or more incidents for the person in the first table) linked through foreign key(nameID). I think the problem is what kind of join to use and how to use the WHERE clause.
Thanks.
More information:
#Tim - Isn't the user input into one or more fields the filter or it is the WHERE Clause? The user doesn't have to fill in all the fields. Thats where I am getting lost. The user is trying to find the incident to update it. Does this help?
Also I have to use "Like%LName%" in the Where clause to get all the names if they don't enter the entire name.
My query looks like this:
Protected Sub BtnSearch_Click(sender As Object, e As EventArgs) Handles BtnSearch.Click
Dim strSearch As String
strSearch = "SELECT tblPatron.LName, tblPatron.FName, tblIncident.CreatedBy, "
strSearch = strSearch + "tblIncident.Inci_ID, tblIncident.Inci_date, tblIncident.Inci_type, tblIncident.Library, "
strSearch = strSearch + "tblIncident.PatronName, tblIncident.Location "
strSearch = strSearch + "FROM tblPatron INNER JOIN tblIncident ON tblPatron.PatronID = tblIncident.PatronID "
strSearch = strSearch + "WHERE "
strSearch = strSearch + "(tblPatron.LName Like '%" + txtLName.Text.ToString() + "%') "
strSearch = strSearch + "AND (tblPatron.FNAME Like '%" + txtFName.Text.ToString() + "%')"
strSearch = strSearch + "AND (tblIncident.Inci_ID ='" + strInciNum.Text.ToString() + "')"
strSearch = strSearch + "AND (tblIncident.Inci_date = '" + txtInciDate.Text.ToString() + "')"
strSearch = strSearch + "AND (tblIncident.Inci_type = '" + ddInciCat.SelectedValue.Trim + "')"
strSearch = strSearch + "AND (tblIncident.Library = '" + ddLib.SelectedValue.Trim + "')"
SearchPDS.SelectCommand = strSearch
SearchPDS.DataBind()
GridSearchResults.DataBind()
GridSearchResults.Visible = True
End Sub

Answer 1

do this:
SELECT A.FirstName, A.LastName, B.IncidentNumber, B.Date, B.Place, B.CreatedBy
FROM Name A INNER JOIN Incident B
ON A.NameID = B.NameID

Answer 2

SELECT firstname, lastname, incidentnumber, date, place, createdby
FROM name n
INNER JOIN incident i ON n.nameID = i.nameID
WHERE firstname LIKE '%'+#firstname+'%'
AND lastname LIKE '%'+#lastname+'%'
Where #firstname and #lastname are parameters containing values from the search fields
In your string concatenation style, just add txtFName.Text.ToString() and txtLName.Text.ToString() into the string in place of those parameters.

Answer 3

I took the suggestion of logixologist. On the click event I added multiple if statements to check for the null value and then add build the query string. At the same time I made one of the dropdown to be a default value instead of "Select" and that would be my starting Where parameter. This works for me now. There might be a better way of writing the query, I am just beginner with asp.net
Thanks for all your replies. I love this forum.

Answer 4

What you need is dynamic sql. Basically you start by declaring a varchar(max)
DECLARE #Sql as varchar(max)
Then you will set it to the base SQL Statement:
SET #SQL = 'SELECT A.FirstName, A.LastName, B.IncidentNumber, B.Date, B.Place, B.CreatedBy
FROM Name A INNER JOIN Incident B
ON A.NameID = B.NameID where lastname IS NOT null ' -- PUT IN A WHERE CLAUSE THAT WILL ALWAYS BE TRUE
---Here is the concept in pseudo code
IF #lastname is not null
BEGIN
SET #SQL = #SQL + 'and lastname = '%' + #lastname + '%'
END
IF #FIRSTNAMEis not null
BEGIN
SET #SQL = #SQL + 'and FIRSTNAME = '%' + #FIRSTNAME+ '%'
END
At the end
EXEC (#SQL)
This will give you any option they put in.