Coverting MySQL查询火力数据库

Question

任何人都可以知道如何这个MySQL查询转换为火力数据库查询（安卓）

SELECT * FROM chat_info 
WHERE receiver = '$sender' 
    and sender= '$receiver' 
UNION 
    SELECT * 
    FROM chat_info 
    WHERE sender='$sender' 
     and receiver='$receiver' 
ORDER BY sno 
DESC 

Answer 1

也从没编码任何Android应用程序，但这里是文档和示例：

documentation.firebase

quickstart-for-android.github

read-&-write-data.firebase

sort-data.firebase

structure-your-database-correctly.firebase

compile 'com.google.firebase:firebase-database:10.2.6' // put this inside the 'build.gradle'-file 

// Configure your database-rules => 

// Read from database and sort => 

private DatabaseReference mDatabase; 
// ... 
mDatabase = FirebaseDatabase.getInstance().getReference(); 

// My top posts by number of stars 
String myUserId = getUid(); 
Query myTopPostsQuery = databaseReference.child("user-posts").child(myUserId) 
     .orderByChild("starCount"); 
myTopPostsQuery.addChildEventListener(new ChildEventListener() { 
    // TODO: implement the ChildEventListener methods as documented above 
    // ... 
}); 

// All examples are copied from firebase.google.com/docs