Get complex response from Android Room with sqlite query - android-sqlite

Question

Based on response to my question here
I have simple table:
id, name, city
and I created a class for it:
#Entity(tableName = "table2")
data class Table2 #JvmOverloads constructor(
#PrimaryKey #ColumnInfo(name = "id") val id: Int? = 0,
#ColumnInfo(name = "name") val name: String? = "",
#ColumnInfo(name = "city") val city: String? = ""
)
I entered next rows:
1 John London
2 Mary Paris
3 John Paris
4 Samy London
I want to get such a result:
London Paris
John 1 1
Mary 0 1
Samy 1 0
Total 2 2
It's not important to get Total row together with John, Mary and Samy lines, now I just want to get a simple response without complex query.
Since I want to get response list of classes containing 3 fields:
city, Int, Int
I created a class for it:
data class CityName constructor(
val name: String? = "",
val countLondon: Int? = 0,
val countParis: Int? = 0
)
Next I tried to create a SQLite query to get a result from Android Room.
#Query("SELECT name,
COUNT(CASE WHEN city = :london THEN 1 ELSE 0 END) 'London',
COUNT(CASE WHEN city = :paris THEN 1 ELSE 0 END) 'Paris'
FROM table2 GROUP BY name")
fun getPivot_CityNameList(london: String, paris: String): List<CityName>
I excluded/included from the query 'London' and 'Paris', I swapped some words etc.
but I always get a result like this:
John, countLondon: null, countParis: null
Mary, countLondon: null, countParis: null
Samy, countLondon: null, countParis: null
It's easy to get subset from a table, like city and id or to get only a count of some field but
I have no idea how to combine subset (name) with two counts in one response.
What is wrong: my query or CityName class response?
How to fix it?
ANSWER
The correct query is
SELECT name,
COUNT(CASE WHEN city = :london THEN 1 END) as countLondon,
COUNT(CASE WHEN city = :paris THEN 1 END) as countParis
FROM table2 GROUP BY name
as mentioned in the accepted answer I missed as countLondon
but also I deleted ELSE 0 from CASE statement

Answer 1

Your CityName fields' names should match your query's columns' aliases.
That's how Room then copies values from SQLite cursor to fields of this class.
So change aliases for columns, and your code should work:
#Query("SELECT name,
COUNT(CASE WHEN city = :london THEN 1 ELSE 0 END) as countLondon, // <- change here
COUNT(CASE WHEN city = :paris THEN 1 ELSE 0 END) as countParis // <- change here
FROM table2 GROUP BY name")
fun getPivot_CityNameList(london: String, paris: String): List<CityName>