访问SELECT语句和硬编码值

Question

这是我的VB SQL语句，它应用于Form_Current上未绑定列表框的rowsource：

SelectionSQL = "SELECT tbl_Patches_Cisco_SAs_Applicability.PatchID, tbl_Patches_Cisco_SAs_Applicability.OS 
      FROM tbl_Patches_Cisco_SAs_Applicability 
      WHERE (((tbl_Patches_Cisco_SAs_Applicability.PatchID)=[Forms]![Patch_Management_Cisco_Stage2]![Publication_ID]));"

效果很好，唯一的问题是我希望rowsource包含＆＃34; NA＆＃34;的硬编码值，而不必创建关联的记录。这可能吗？怎么样？即以某种方式将NA添加到rowsource？

Answer 1

您可以使用UNION查询，该查询会为您现有的内容添加一行伪造值。

SELECT a.PatchID, a.OS
FROM tbl_Patches_Cisco_SAs_Applicability AS a
WHERE a.PatchID=[Forms]![Patch_Management_Cisco_Stage2]![Publication_ID]
UNION ALL
SELECT 0 AS PatchID, 'NA' AS OS
FROM Dual;

Dual 可以是任何只返回一行的表或查询。我为此目的使用自定义表：CreateDualTable()

Answer 2

一种可能性是使用UNION查询：

SelectionSQL = "SELECT tbl_Patches_Cisco_SAs_Applicability.PatchID,
    tbl_Patches_Cisco_SAs_Applicability.OS FROM tbl_Patches_Cisco_SAs_Applicability WHERE
    (((tbl_Patches_Cisco_SAs_Applicability.PatchID)=[Forms]![Patch_Management_Cisco_Stage2]![Publication_ID])) 
    UNION SELECT TOP 1 0, 'NA' FROM tbl_Patches_Cisco_SAs_Applicability"