VBA - 创建基于条件的 SQL 查询

Question

我对 VBA 很陌生，我想找到一种更简单的方法来创建 SQL 查询。 我有 4 个组合框，查询取决于它们是否被填充。其中一个组合框链接到带有多个复选框的用户表单，这些复选框将添加到查询中。

这是我目前拥有的代码，我想增加用户表单条件：

If Sheets("Home Page").opecbbx.Value <> "" And Sheets("Home Page").wellchk.Value = False Then 'contractor only
        op = Sheets("Home Page").opecbbx.Value

                If Sheets("Home Page").sizcbbx.Value <> "" Then 'contractor and size
                    'Create SQL statement for filtering.
                    siz = Sheets("Home Page").sizcbbx.Value
                    SQL = "SELECT * FROM Filter Where contractor Like '%" & op & "%' And size_sec Like '%" & siz & "%';"

                Else

                    SQL = "SELECT * FROM Filter Where contractor Like '%" & op & "%';"

                End If

    ElseIf Sheets("Home Page").wellchk.Value = True And Sheets("Home Page").opecbbx.Value <> "" Then 'contractor and well
    op = Sheets("Home Page").opecbbx.Value

                If Sheets("Home Page").sizcbbx.Value <> "" Then 'contractor, size and well

                            siz = Sheets("Home Page").sizcbbx.Value
                            SQL = "SELECT * FROM Filter Where contractor Like '%" & op & "%' And size_sec Like '%" & siz & "%' And ID_NOC = '" & well & "';"

                Else

                    SQL = "SELECT * FROM Filter Where contractor Like '%" & op & "%' and ID_NOC='" & well & "';"

                End If

    ElseIf Sheets("Home Page").wellchk.Value = True Then

                If Sheets("Home Page").sizcbbx.Value <> "" Then 'size and well

                    siz = Sheets("Home Page").sizcbbx.Value
                    SQL = "SELECT * FROM Filter Where size_sec Like '%" & siz & "%' And ID_NOC = '" & well & "';"

                Else

                     SQL = "SELECT * FROM Filter Where ID_NOC='" & well & "';"

                End If

    ElseIf Sheets("Home Page").sizcbbx.Value <> "" And Sheets("Home Page").wellchk.Value = False And Sheets("Home Page").opecbbx.Value = "" Then 'size only

                siz = Sheets("Home Page").sizcbbx.Value
                SQL = "SELECT * FROM Filter Where size_sec Like '%" & siz & "%';"

    'Formation only
    ElseIf Sheets("Home Page").wellchk.Value = False And Sheets("Home Page").opecbbx.Value = "" And Sheets("Home Page").sizcbbx.Value = "" Then

                SQL = "SELECT * FROM Filter"

    End If

如何在不添加大量新条件的情况下做到这一点？

谢谢

Answer 1

我可以在这里给出一个一般性的答案，这可能需要一些按摩才能在 VBA 中工作。您可以像这样使用灵活的预处理语句：

SELECT *
FROM Filter
WHERE
    (contractor LIKE ? OR contractor IS NULL) AND
    (size_sec LIKE ? OR size_sec IS NULL) AND
    (ID_NOC = ? OR ID_NOC IS NULL);

对于每个占位符?，您可以绑定组合框中的值（如果已定义），或者仅绑定NULL。例如，对于contractor 占位符，如果已定义，您将绑定op，否则绑定NULL。这种方法的工作方式是，如果给定的标准是NULL，那么它就会被忽略。因此，如果您只有组合框中的三个可用值之一，那么只有它会用于在 WHERE 子句中进行过滤。