Simple joint query

[Razvan Bunea]

Hi,

Been playing around with trying to write a simple joint typed query between 2 collection but for the hell of me couldn't figure out form the documentation or the AggregateTest 

I have these 2 collections objects

data class UserDb(@BsonId val login: String, val password: String)
data class EmailDb(@BsonId val login: String, val email: String)

And I want to have in return

data class UserWithEmail(val login: String, val password: String, val email: String?)

I came this far: 

aggregate<UserWithEmail>(

        lookup(

            from = "emails",

            localField = UserDb::login.name,

            foreignField = EmailDb::login.name,

            newAs = UserWithEmail::email.name

        ),

        UserWithEmail::email.unwind(),

        project(

            UserWithEmail::login to UserDb::login,

            UserWithEmail::password to UserDb::password,

            UserWithEmail::email to "?"

        )

    )

But don't know what to put instead if "?"  and each entry is repeted twice

I tried to write the lookup with a variables, result, pipeline as in your Test exemple but didn't manage to make it work at all. 

Thanks in advance.

[zigzago]

Hi,

This code should work:

aggregate<UserWithEmail>(

        lookup(

            from = "emails",

            localField = UserDb::login.name,

            foreignField = EmailDb::login.name,

            newAs = UserWithEmail::email.name

        ),

        UserWithEmail::email.unwind(),

        project(

            UserWithEmail::login from UserDb::login,

            UserWithEmail::password from UserDb::password,

            UserWithEmail::email from UserWithEmail::email

        )

    )

HTH