实时更改子窗体数据源的代码中like语句该如何写?

Private Sub Command13_Click()
      Dim strsql As String '设置一个SQL变量
      Dim sm As String '设置一个目录变量
     
      If Combo9 = "必备" Then
         strsql = "select * from 必备查询(有订数) where 书名 Like " * " sm " * ""
         Me.总体查询子窗体.Form.RecordSource = strsql
         Me.总体查询子窗体.Requery
      ElseIf Combo9 = "闽版" Then
         strsql = "select * from 闽版查询(有订数) where 书名 Like " * " sm " * ""
         Me.总体查询子窗体.Form.RecordSource = strsql
         Me.总体查询子窗体.Requery
      ElseIf Combo9 = "外版1" Then
         strsql = "select * from 外版1查询(有订数) where 书名 Like " * " sm " * ""
         Me.总体查询子窗体.Form.RecordSource = strsql
         Me.总体查询子窗体.Requery
      ElseIf Combo9 = "外版2" Then
         strsql = "select * from 外版2查询(有订数) where 书名 Like " * " sm " * ""
         Me.总体查询子窗体.Form.RecordSource = strsql
         Me.总体查询子窗体.Requery
      ElseIf Combo9 = "音像" Then
         strsql = "select * from 音像查询(有订数) where 书名 Like " * " sm " * ""
         Me.总体查询子窗体.Form.RecordSource = strsql
         Me.总体查询子窗体.Requery
      End If
End Sub

以上代码运行后，提示strsql = "select * from 必备查询(有订数) where 书名 Like " * " sm " * ""一行出错，我不知道like后要用什么表达式，能帮我改改吗，我的目的是根据sm书名变量和combo9组合框的值，来判断子窗体内的数据源指向哪个查询，并查询符合sm书名的记录有多少条，在子窗体中显示出来。另外总体代码应该没有错吧?请大侠们帮帮我，谢谢了