Java Android数据库的组合查询

我有一个连接查询，可以从三个表中查找数据，所以如何知道数据是从哪个表中创建的

select text from table1 where title ='Vishal'  union all select text from table2 where title ='Vishal'  union all select text from table3 where title ='Vishal'

此查询为我提供了所需的输出，但我想知道

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标题匹配从哪个表和我想得到的表名这不是一个聪明的解决方案，但是怎么样

select text as text1, null as text2, null as text3 from table1 where title ='Vishal'
union all
select null as text1, text as text2, null as text3 from table2 where title ='Vishal'
union all
select null as text1, null as text2, text as text3 from table3 where title ='Vishal'


// Run your sql query

for (results){
    if (results[i].text1 != null){
        // match table1
    }
    else if (results[i].text2 != null){
        // match table2
    }
    else if (results[i].text3 != null){
        // match table3
    }
}

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可以向结果中添加具有常量值的列：

select text, 'table1' as source from table1 where title ='Vishal'
union all
select text, 'table2'           from table2 where title ='Vishal'
union all
select text, 'table3'           from table3 where title ='Vishal'

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你需要更清楚地回答你的问题。您的答案可以是联合、联接、子查询或其他。没有足够的信息。详细描述这三个表的模式以及您想要做的事情。您可以用数据返回一些提示来识别，并用一些示例简要说明您的问题现在感觉舒服了吗？