VB 2012 - Help Finding Specific Numbers in a Database Column and Count the Number of Times They Appear.

Question

Hello,
I am doing a project that uses MS Access to access data about a baseball team . The MS Access Database provides the names, addresses, and age of the players. All the players are 12, 13, or 14 years old. I need to display the average age for the team on a
label, which was easy. The problem is that I also have to display the number of players who are 12, 13, and 14 years old and I have no idea how to do that.
Here is my code so far:
Public Class frmBaseball
Private Sub TeamBindingNavigatorSaveItem_Click(sender As Object, e As EventArgs) Handles TeamBindingNavigatorSaveItem.Click
Me.Validate()
Me.TeamBindingSource.EndEdit()
Me.TableAdapterManager.UpdateAll(Me.LittleLeagueDataSet)
End Sub
Private Sub frmBaseball_Load(sender As Object, e As EventArgs) Handles MyBase.Load
'TODO: This line of code loads data into the 'LittleLeagueDataSet.Team' table. You can move, or remove it, as needed.
Me.TeamTableAdapter.Fill(Me.LittleLeagueDataSet.Team)
End Sub
Private Sub btnAges_Click(sender As Object, e As EventArgs) Handles btnAges.Click
Dim strSql As String = "SELECT * FROM Team"
Dim strPath As String = "Provider=Microsoft.ACE.OLEDB.12.0 ;" & "Data Source=e:\LittleLeague.accdb"
Dim odaTeam As New OleDb.OleDbDataAdapter(strSql, strPath)
Dim datAge As New DataTable
Dim intCount As Integer = 0
Dim intTotalAge As Integer
Dim decAverageAge As Decimal
odaTeam.Fill(datAge)
odaTeam.Dispose()
For intCount = 0 To datAge.Rows.Count - 1
intTotalAge += Convert.ToInt32(datAge.Rows(intCount)("Age"))
decAverageAge = Convert.ToDecimal(intTotalAge / datAge.Rows.Count)
Next
lblAverage.Visible = True
lblAverage.Text = "The average age of the team is " & decAverageAge.ToString("N2")
lbl12.Text = "The number of 12 year olds is "
lbl13.Text = "The number of 13 year olds is "
lbl14.Text = "The number of 14 year olds is "
lbl12.Visible = True
lbl13.Visible = True
lbl14.Visible = True
End Sub
End Class
I think I should use a For..Next loop but I don't know how to identify and match using this database, and then count how many repeated 12, 13, 14 years old there are.
Any help would be really appreciated.

Answer 1

Hello,
Conceptually speaking you would group the data and count. Beings this is school work the demo below is a static example and not suitable for your assignment, its to show a point. Now if you have learned about LINQ and Lambda this logic can apply to your
question but need to work out using this your data which can be done. If not look at using SQL Grouping.
Example of SQL grouping and count
select country, count(country) as count from customers group by country
Module Module1
Public Sub GroupingDemo()
Dim dt As DataTable = SimulateLoadFromDatabase()
Dim TeamData = dt.AsEnumerable.GroupBy(
Function(student) student.Field(Of Integer)("Age")) _
.Select(Function(group) New With
Key .Value = group.Key,
Key .Info = group.OrderByDescending(
Function(x) x.Field(Of String)("Name"))}) _
.OrderBy(
Function(group) group.Info.First.Field(Of Integer)("age"))
Dim dictData As New Dictionary(Of String, String)
For Each group In TeamData
Console.WriteLine("Group: {0} count: {1} ", group.Value, group.Info.Count)
dictData.Add(group.Value.ToString, group.Info.Count.ToString)
' The following is not needed but good to show
For Each item In group.Info
Console.WriteLine(" {0} {1}",
item.Field(Of Integer)("Identifier"),
item.Field(Of String)("Name"))
Next
Next group
Console.WriteLine()
Console.WriteLine("This data can be used to populate control text")
For Each Item As KeyValuePair(Of String, String) In dictData
Console.WriteLine("{0} {1}", Item.Key, Item.Value)
Next
End Sub
Private Function SimulateLoadFromDatabase() As DataTable
Dim dt As New DataTable With {.TableName = "MyTable"}
dt.Columns.Add(New DataColumn With {.ColumnName = "Identifier", .DataType = GetType(Int32),
.AutoIncrement = True, .AutoIncrementSeed = 1})
dt.Columns.Add(New DataColumn With {.ColumnName = "Name", .DataType = GetType(String)})
dt.Columns.Add(New DataColumn With {.ColumnName = "Age", .DataType = GetType(Int32)})
dt.Rows.Add(New Object() {Nothing, "Bill", 13})
dt.Rows.Add(New Object() {Nothing, "Karen", 14})
dt.Rows.Add(New Object() {Nothing, "Jim", 13})
dt.Rows.Add(New Object() {Nothing, "Paul", 15})
dt.Rows.Add(New Object() {Nothing, "Mike", 14})
dt.Rows.Add(New Object() {Nothing, "Jill", 13})
Return dt
End Function
End Module
Output in the IDE output window
Group: 13 count: 3
3 Jim
6 Jill
1 Bill
Group: 14 count: 2
5 Mike
2 Karen
Group: 15 count: 1
4 Paul
This data can be used to populate control text
13 3
14 2
15 1
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