Question

检查科学复选框时。 Science将在DataGridView中显示但是当我检查Reading和Science时，这两个主题无法在DataGridView上显示。解决此问题的最佳方法（代码）是什么？提前谢谢。

`Public com As New MySql.Data.MySqlClient.MySqlCommand
 Public da As New MySql.Data.MySqlClient.MySqlDataAdapter
 Public dr As MySql.Data.MySqlClient.MySqlDataReader
 Public dt As New DataTable
 Public dt2 As New DataTable
 Public ds As DataSet
 Dim strSQL As String
 Dim strSQL2 As String

 Private Sub gbsubject_Enter(sender As Object, e As EventArgs) Handles gbsubject.Enter

 Dim SDA As New MySql.Data.MySqlClient.MySqlDataAdapter
 Dim dbDataSet As New DataTable
 Dim bSource As New BindingSource

 If cbxscience.Checked = True Then

        con.Close()
        con.Open()

        strSQL2 = "SELECT subject_tbl.subject, lessonplan_tbl.lessontitle, kind_tbl.kind FROM kind_tbl INNER JOIN(lessonplan_tbl INNER JOIN(subject_tbl INNER JOIN skul_tbl ON subject_tbl.subjectID = skul_tbl.subjectID) ON lessonplan_tbl.lessonplanID = skul_tbl.lessonplanID) ON kind_tbl.kindID = skul_tbl.kindID WHERE subject_tbl.subject = '" & "SCIENCE" & "'"

        dgvlessonplan.AutoSizeRowsMode = _
   DataGridViewAutoSizeRowsMode.None


        com = New MySql.Data.MySqlClient.MySqlCommand(strSQL2, con)
        SDA.SelectCommand = com
        SDA.Fill(dbDataSet)
        bSource.DataSource = dbDataSet
        dgvlessonplan.DataSource = bSource
        SDA.Update(dbDataSet)
        con.Close()

    End If

    If cbxreading.Checked And cbxscience.Checked Then

        con.Close()
        con.Open()

        strSQL2 = "SELECT subject_tbl.subject, lessonplan_tbl.lessontitle, kind_tbl.kind FROM kind_tbl INNER JOIN(lessonplan_tbl INNER JOIN(subject_tbl INNER JOIN skul_tbl ON subject_tbl.subjectID = skul_tbl.subjectID) ON lessonplan_tbl.lessonplanID = skul_tbl.lessonplanID) ON kind_tbl.kindID = skul_tbl.kindID WHERE subject_tbl.subject = '" & "READING" & "' and subject_tbl.subject = '" & "SCIENCE" & "'"

        dgvlessonplan.AutoSizeRowsMode = _
   DataGridViewAutoSizeRowsMode.None


        com = New MySql.Data.MySqlClient.MySqlCommand(strSQL2, con)
        SDA.SelectCommand = com
        SDA.Fill(dbDataSet)
        bSource.DataSource = dbDataSet
        dgvlessonplan.DataSource = bSource
        SDA.Update(dbDataSet)
        con.Close()

    End If`

Answer 1

您需要在OR变量中使用AND而不是strSQL2。

所以，改变一下：

 strSQL2 = "SELECT subject_tbl.subject, lessonplan_tbl.lessontitle, kind_tbl.kind FROM kind_tbl INNER JOIN(lessonplan_tbl INNER JOIN(subject_tbl INNER JOIN skul_tbl ON subject_tbl.subjectID = skul_tbl.subjectID) ON lessonplan_tbl.lessonplanID = skul_tbl.lessonplanID) ON kind_tbl.kindID = skul_tbl.kindID WHERE subject_tbl.subject = '" & "READING" & "' and subject_tbl.subject = '" & "SCIENCE" & "'"

到此：

 strSQL2 = "SELECT subject_tbl.subject, lessonplan_tbl.lessontitle, kind_tbl.kind FROM kind_tbl INNER JOIN(lessonplan_tbl INNER JOIN(subject_tbl INNER JOIN skul_tbl ON subject_tbl.subjectID = skul_tbl.subjectID) ON lessonplan_tbl.lessonplanID = skul_tbl.lessonplanID) ON kind_tbl.kindID = skul_tbl.kindID WHERE subject_tbl.subject = 'READING' OR subject_tbl.subject = 'SCIENCE'"

无法解决此查询复选框 - VB.net MYSQL查询

1 个答案: