这是今天的大喜事！ 我企盼已经久的一个问题终于得到解决了！ 以前需要对一个企业网站进行全站搜索的时候，如果是sql server，那就用临时表，把产品表和新闻填充到临时表然后再从临时表中搜索，如果是access，那就没有办法了，因为很多资料都说了access不支
这是今天的大喜事！
我企盼已经久的一个问题终于得到解决了！
以前需要对一个企业网站进行全站搜索的时候，如果是sql server，那就用临时表，把产品表和新闻填充到临时表然后再从临时表中搜索，如果是access，那就没有办法了，因为很多资料都说了access不支持临时表。
昨天下午，在用asp.net做一个access的项目，其中Repeater不支持分页，access也不支持存储过程。DataSet也不支持分页，最后只好在sql语句上寻找办法了。经过反复的研究，最后找到一个办法并且成功通过了。在这个过程中，用到一个UNION，在这个应用中，UNION是把同一个表的两个查询结果合并在一起的。我在反复的思考过程中想到了，能不能把两个不同的表合并到一起呢？
想过了之后，就决定动手做一下，找到以前某个网站的数据里，里面有[News]和[Products]两个表。然后分别从两个各自取出几个字段尝试合并，第一次出现个问题，就是两个查询的列数不同，不能合并，这是我的疏忽，改正之后竟然成功了。心中大喜。马上继续试验，再用AS添加了一个名称为‘t’的列，用来标识每一列的来源，因为，对于这两个表的数据查询结果虽然需要合并，但是查询之后再显示到网页上，点击之后应该链接到不同的程序上显示详细的地址，所以还要是需要区分的。于是最后的结果就是下面这条：
select Id,[P_Name],[P_Update],'product' AS t From [product]
UNION ALL
select id,N_title,N_Update,'news' AS t From [News]
需要注意的就是，这样的结果，会是4列，4列的名称分别是id,P_Name,P_Update,t。N_title这个名称就不再使用了。所以是下面的结果
如果想要得到更理想的结果那就给列用AS起上相应的别名：
select Id,[P_Name] AS [Title],[P_Update] AS [PubDate],'product' AS t From [product]
UNION ALL
select id,N_title,N_Update,'news' AS t From [News]
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