android中的不明确的列名

Question

如果我有两个表,有列

TABLE 1: [_id,info]

TABLE 2: [_id,date]

并创建一个连接如何解决生成的Cursor中的_id列的模糊,并只访问表2的列_id？

Answer 1

通常,如果您有不明确的列名,可以使用别名来区分它们.

SELECT
    t1._id as t1_id,
    t2._id as t2_id
FROM ...
JOIN ...

在这种情况下,我猜你正在加入_id字段是平等的.然后你只能选择一次:

SELECT
    T2._id as id
    T1.info,
    T2.date
FROM table1 AS T1
JOIN table2 AS T2
ON T1._id = T2._id