是否可以在[ID]中添加条件而不在左连接中的[TypeID]中添加标准?
SQL = "SELECT " & _
"ADate As NewDate, " & _
"tblA.TypeID as ID, " & _
"tblAB.TypeControl as ControlID " & _
"FROM tblA " & _
"LEFT OUTER JOIN tblAB " & _
"ON tblAB.TypeID = tblA.TypeID " & _
"WHERE tblA.TypeID = " & Counter & " " & _ => Delete this one.
"UNION ALL SELECT " & _
"BDate As NewDate, " & _
"tblB.TypeID as ID, " & _
"tblAB.TypeControl as ControlID " & _
"FROM tblB " & _
"LEFT OUTER JOIN tblAB " & _
"ON tblAB.TypeID = tblB.TypeID " & _
"WHERE tblB.TypeID = " & Counter & " " & _ => Delete this one.
===
and place one WHERE on ID here
"WHERE ID = " & Counter & " " & _ => Like this one. But I am getting an error.
===
"ORDER BY NewDate;"
从tblA和tblB中删除两个WHERE。 最后在ID中添加一个。 并创建这个。
SQL = "SELECT " & _
"ADate As NewDate, " & _
"tblA.TypeID as ID, " & _
"tblAB.TypeControl as ControlID " & _
"FROM tblA " & _
"LEFT OUTER JOIN tblAB " & _
"ON tblAB.TypeID = tblA.TypeID " & _
"UNION ALL SELECT " & _
"BDate As NewDate, " & _
"tblB.TypeID as ID, " & _
"tblAB.TypeControl as ControlID " & _
"FROM tblB " & _
"LEFT OUTER JOIN tblAB " & _
"ON tblAB.TypeID = tblB.TypeID " & _
"WHERE tblB.TypeID = " & Counter & " " & _
"WHERE ID = " & Counter & " " & _
"ORDER BY NewDate;"
提前谢谢。
答案 0 :(得分:1)
只能通过将整个查询包装在子查询中来检查ID,然后检查外部查询中的ID,例如:
SELECT * FROM (
SELECT " & _
"ADate As NewDate, " & _
"tblA.TypeID as ID, " & _
"tblAB.TypeControl as ControlID " & _
"FROM tblA " & _
"LEFT OUTER JOIN tblAB " & _
"ON tblAB.TypeID = tblA.TypeID " & _
"UNION ALL SELECT " & _
"BDate As NewDate, " & _
"tblB.TypeID as ID, " & _
"tblAB.TypeControl as ControlID " & _
"FROM tblB " & _
"LEFT OUTER JOIN tblAB " & _
"ON tblAB.TypeID = tblB.TypeID "
) WHERE ID = " & Counter & "
但是,根据数据库引擎如何优化它,可能需要更长时间才能执行。我建议您不要这样做,并按原样保留查询。
(另外,我把引号弄得乱七八糟,因为你的问题不管怎么说都没有。)