VBA-数据库查询实例

1.首先我们得做一个窗体，其布局和运行效果如下

2.我们要理清思路，首先窗体在运行时就应该将部门加载进去，并且将重复的部门剔除掉

Private Sub UserForm_Initialize()
Set con = New ADODB.Connection
With con
.Provider = "microsoft.ace.oledb.12.0"
.ConnectionString = "data source=" & ThisWorkbook.Path & "\学生管理.accdb"
.Open
End With
'提取
Dim sql As String
sql = "select distinct 部门 from 员工"
Set rs = New ADODB.Recordset
rs.Open sql, con, adOpenKeyset, adLockOptimistic '产生记录集
Dim i As Integer
'将记录集中的部门名称显示到listbox1 列表框中
With ListBox1
    .Clear
    For i = 1 To rs.RecordCount
    .AddItem rs("部门")
    rs.MoveNext '将记录集中的指针指向下一条记录
    Next i
End With
rs.Close
End Sub

3.我们要实现的是在选择部门中选择部门后，将这个部门的员工编号，姓名显示在选择员工的列表框中

'单击列表框，查询员工信息
Private Sub ListBox1_Click()
    Dim sql As String
    sql = "select 编号,姓名 from 员工 where 部门='" & ListBox1.Value & " 'order by 编号"
    rs.Open sql, con, adOpenKeyset, adLockOptimistic '产生记录集
    Dim i As Integer
    With ListBox2
    .Clear
    For i = 1 To rs.RecordCount
    .AddItem rs("编号") & Space(2) & rs("姓名")
    rs.MoveNext '将记录集中的指针指向下一条记录
    Next i
End With
rs.Close
End Sub

 4.将选择员工后，把员工的对应信息显示在对应的文本框中，便可以实现查询功能

'单击列表框，将对应的信息显示在对应的文本框中
Private Sub ListBox2_Click()
Dim sql As String
sql = "select * from 员工 where 编号='" & Left(ListBox2.Value, 6) & "'"
rs.Open sql, con, adOpenKeyset, adLockOptimistic
Dim arr, i As Integer
arr = Array("TextBox1", "TextBox2", "TextBox3", "TextBox4", "TextBox5", "TextBox6", "TextBox7", "TextBox8", "TextBox9", "TextBox10")
For i = 0 To 7
Me.Controls(arr(i)).Value = rs.Fields(i)
Next i
rs.Close
End Sub

5.完整代码及解释如下

Option Explicit
Dim con As ADODB.Connection
Dim rs As ADODB.Recordset
'关闭数据库连接，关闭窗体，释放变量空间
Private Sub CommandButton1_Click()
con.Close
Set rs = Nothing
Set con = Nothing
Unload Me
End Sub
'单击列表框，查询员工信息
Private Sub ListBox1_Click()
    Dim sql As String
    sql = "select 编号,姓名 from 员工 where 部门='" & ListBox1.Value & " 'order by 编号"
    rs.Open sql, con, adOpenKeyset, adLockOptimistic '产生记录集
    Dim i As Integer
    With ListBox2
    .Clear
    For i = 1 To rs.RecordCount
    .AddItem rs("编号") & Space(2) & rs("姓名")
    rs.MoveNext '将记录集中的指针指向下一条记录
    Next i
End With
rs.Close
End Sub
'单击列表框，将对应的信息显示在对应的文本框中
Private Sub ListBox2_Click()
Dim sql As String
sql = "select * from 员工 where 编号='" & Left(ListBox2.Value, 6) & "'"
rs.Open sql, con, adOpenKeyset, adLockOptimistic
Dim arr, i As Integer
arr = Array("TextBox1", "TextBox2", "TextBox3", "TextBox4", "TextBox5", "TextBox6", "TextBox7", "TextBox8", "TextBox9", "TextBox10")
For i = 0 To 7
Me.Controls(arr(i)).Value = rs.Fields(i)
Next i
rs.Close
End Sub
Private Sub UserForm_Initialize()
Set con = New ADODB.Connection
With con
.Provider = "microsoft.ace.oledb.12.0"
.ConnectionString = "data source=" & ThisWorkbook.Path & "\学生管理.accdb"
.Open
End With
'提取
Dim sql As String
sql = "select distinct 部门 from 员工"
Set rs = New ADODB.Recordset
rs.Open sql, con, adOpenKeyset, adLockOptimistic '产生记录集
Dim i As Integer
'将记录集中的部门名称显示到listbox1 列表框中
With ListBox1
    .Clear
    For i = 1 To rs.RecordCount
    .AddItem rs("部门")
    rs.MoveNext '将记录集中的指针指向下一条记录
    Next i
End With
rs.Close
End Sub