My database structure looks like this ,
-posts
    -postId1
        -tags
            1:A
            2:B
            3:D
        -text:Hello
    -postId2
        -tags
            1:B
            2:D
        -text:How are you?
    -postId3
        -tags   
            1:A
            2:C
        -text:Hello World
Now, I want to retrieve the text of those postIds which contains tags B or D, Which one will be the best approach to achieve this ?
