mysql - 是否可以使用 2 个不同的表更新某个列值并删除它？

Question

  For k As Integer = Me.DataGridView1.SelectedRows.Count - 1 To 0 Step -1
                    Dim Query1 As String
                    Query1 = "Update librarydb.blist SET quantity=(quantity + 1) where quantity = '" & Me.DataGridView1.SelectedRows(k).Cells(0).Value.ToString & "'"
                    command1 = New MySqlCommand(Query1, MysqlConn1)
                    SDA1.SelectCommand = command1
                    SDA1.Fill(dbDataSet1)
                    bSource1.DataSource = dbDataSet1
                    Me.DataGridView1.DataSource = bSource1
                    SDA1.Update(dbDataSet1)
                    Dim Query2 As String
                    For j As Integer = Me.DataGridView1.SelectedRows.Count - 1 To 0 Step -1
                        Query2 = "delete from returnlist where student_id= '" & Me.DataGridView1.SelectedRows(j).Cells(1).Value.ToString & "'"
                        command1 = New MySqlCommand(Query1, MysqlConn1)
                        SDA1.SelectCommand = command1
                        SDA1.Fill(dbDataSet1)
                        bSource1.DataSource = dbDataSet1
                        Me.DataGridView1.DataSource = bSource1
                        SDA1.Update(dbDataSet1)
                    Next
                Next

我想做的是在第一个查询中它将在 blist 表的第 0 列中更新。在第二个查询中它将删除 returnlist 表中的选定行。

Answer 1

您可以执行任意数量的查询。您可以像这样组合查询字符串:

"UPDATE tableA set fieldA = value; " +
"DELETE tableB WHERE fieldB = value"

因此您可以放置​​多个查询并执行它们，您需要用分号分隔它们。

因此，您可以将 2 个查询组合到一个查询变量中:

Dim Query As String
Query = "delete from returnlist where quantity= '" & Me.DataGridView1.SelectedRows(k).Cells(0).Value.ToString & "'; " &
"delete from returnlist where quantity= '" & Me.DataGridView1.SelectedRows(k).Cells(0).Value.ToString & "'"

然后您可以同时执行这两个命令。