联盟与多台不同的列如何

Question

结合我有一个表牙科 列是（标题，出版社，关键词，主题）和另一 表，我有爱思唯尔 列是（作者，标题，期刊，出版社，抽象，关键字 和第三表圣人 列是（作者，标题，期刊，出版商，摘要，关键字）。 问题是我怎样才能将这些表通过union组合起来，以便我可以从所有三个表中的数据库中获取数据。 我不能使用只能加入我有工会所以建议如果，如果有对此

当我使用任何解决方案选项：

select null author, Title, null journal, publisher, subject as abstract, keyword from table1 
    union 
select author, title, journal, publisher, abstract,keyword from table2 

select null author,Title,null journal,publisher,null abstract,subject as abstract,keyword from dental 
    where (Author LIKE '%Bastone%' or Title LIKE '%Bastone%' or Journal LIKE '%Bastone%' 
     or Publisher LIKE '%Bastone%' or abstracts LIKE '%Bastone%' or Keyword LIKE '%Bastone%' 
     or Title LIKE '%Bastone%' or Publisher LIKE '%Bastone%' or Keyword LIKE '%Bastone%' 
     or Subject LIKE '%Bastone%') 
    union 
select author, title, journal, publisher, abstract,keyword, null subject from elsevier 
    where(Author LIKE '%Bastone%' or Title LIKE '%Bastone%' or Journal LIKE '%Bastone%' 
     or Publisher LIKE '%Bastone%' or abstracts LIKE '%Bastone%' or Keyword LIKE '%Bastone%' 
     or Title LIKE '%Bastone%' or Publisher LIKE '%Bastone%' or Keyword LIKE '%Bastone%' 
     or Subject LIKE '%Bastone%') 

收到此错误

#1054 - Unknown column 'Author' in 'where clause'

Answer 1

一种可行的方法可能是：

select null author, Title, null journal, publisher, null abstract, keyword, subject 
    from table1 
union all 
select  author, title,  journal, publisher,  abstract,keyword, null subject 
    from table2 
union all 
select  author, title,  journal, publisher, abstract,keyword, null subject 
    from table3 

如果其中的一些领域都只是“同义词”（例如抽象和主题），你可以通过别名将它们返回到同一列（例如“抽象为主题”）。见下面的例子：

select null author, Title, null journal, publisher, subject as abstract, keyword 
    from table1 
union all 
select  author, title,  journal, publisher,  abstract,keyword 
    from table2 
union all 
select  author, title,  journal, publisher, abstract,keyword 
    from table3 

澄清后的查询

的结构如果需要则申请一个where条件生成的表，你最好将它们包装成一个查询。

例子：

select * from (
    select null author, Title, null journal, publisher, subject as abstract, keyword 
     from table1 
    union all 
    select  author, title,  journal, publisher,  abstract,keyword 
     from table2 
    union all 
    select  author, title,  journal, publisher, abstract,keyword 
     from table3 
) as table_union 
where author like '%string%' 

如果由于某种原因，你不能完成整个查询（即您的查询框架的限制），你可以换单的查询。

所以，你的原始查询可以写成：

select * from (
select null author, Title, null journal, publisher, null abstract, keyword, subject 
    from dental 
union all 
select  author, title,  journal, publisher,  abstract,keyword, null subject 
    from elsevier 
) as table_union 
where (Author LIKE '%Bastone%' 
     or Title LIKE '%Bastone%' 
     or Journal LIKE '%Bastone%' 
     or Publisher LIKE '%Bastone%' 
     or abstract LIKE '%Bastone%' 
     or Keyword LIKE '%Bastone%' 
     or Subject LIKE '%Bastone%' 
) 

或：

select * from (
select null author, Title, null journal, publisher, null abstract, keyword, subject 
    from dental 
) as dental_2 
where (Author LIKE '%Bastone%' 
     or Title LIKE '%Bastone%' 
     or Journal LIKE '%Bastone%' 
     or Publisher LIKE '%Bastone%' 
     or abstract LIKE '%Bastone%' 
     or Keyword LIKE '%Bastone%' 
     or Subject LIKE '%Bastone%' 
) 

union all 

select * from (
select  author, title,  journal, publisher,  abstract,keyword, null subject 
    from elsevier 
) as elsevier_2 
where (Author LIKE '%Bastone%' 
     or Title LIKE '%Bastone%' 
     or Journal LIKE '%Bastone%' 
     or Publisher LIKE '%Bastone%' 
     or abstract LIKE '%Bastone%' 
     or Keyword LIKE '%Bastone%' 
     or Subject LIKE '%Bastone%' 
) 

Answer 2

第二个表格和第三个表格使用别名作为第一个表格字段名称