SQL列合并和聚合函数

Question

我有一个简单的表，有两列（两列感兴趣，只有一个ID）...我有一个ajax搜索，只是寻找关键字...然后发送到我的真实搜索.. ajax搜索不关心它们是什么，但它们需要区别......

如何将两列合并在一起：

City, Country

Krakow, Poland
Warsaw, Poland
Austin, USA
New York, USA
Prague, Czech Republic

所以我会得到

Keyword, Sideinfo

Krakow, Poland
Warsaw, Poland
Austin, USA
Prague, Czech Republic
USA, Country (only once)
Poland, Country
Czech Republic, Country

我试过做一个UNION，但我不确定我怎么做'WHERE LIKE'关键字''

希望有道理......

Answer 1

试试这个。

SELECT Keyword, SideInfo
FROM
(
    SELECT
        DISTINT City as Keyword, Country as SideInfo
    FROM Table

    UNION
    SELECT 
        DISTINCT Country, 'Country'
    FROM Table
) AS InnerQuery
Where Keyword LIKE '%blah%'

Answer 2

这应该这样做：

select distinct country Keyword,'Country' SideInfo from Cities
union all
select City Keyword,Country SideInfo from Cities