In CakePHP 3.X using addCase how should I define a value as a fallback? [duplicate] - cakephp

Question

I'm trying to get a query working using a case statement, and can't figure out how to get the case to return a column value instead of a constant. I have the query working perfectly, except that the column names I'm providing for the results are being quoted or otherwise mishandled by Cake or maybe PDO somewhere down in a layer that I can't dig my way through. I got as far down as bindValue, but none of the documentation I encountered along the way tells me how to do this.
I have found this example comment:
$statement->bindValue(1, 'a title');
$statement->bindValue(2, 5, PDO::INT);
$statement->bindValue('active', true, 'boolean');
$statement->bindValue(5, new \DateTime(), 'date');
but in all these cases, the value provided is a constant. I need to pass in a string that is the name of the column that I want returned.
I tried both 'string' (resulted in quoted column name) and 'integer' (resulted in 0). I tried PDO::FETCH_COLUMN (seemed highly unlikely, but looked like the next best bet from http://php.net/manual/en/pdo.constants.php, and easy to try it...). I tried 'literal', inspired by the way you can put literal strings into expressions (resulted in Error: unknown type "literal"). That error message led me to src/Database/Type.php, but nothing in there helped me either.
So, I'm pretty much stumped. Here's a simple version of the code I have (leaving out a couple of conditions and unrelated columns):
$query = $this->Games->find();
$team_id = $query->newExpr()->addCase(
[$query->newExpr()->eq('Games.status', 'home_default')],
['home_team_id', 'away_team_id'],
['string', 'string']
);
$defaulting = $query
->select([
'id' => $team_id,
'count' => 'COUNT(Games.id)',
])
->where([
'Games.status IN' => ['home_default', 'away_default'],
])
->group('id')
->toArray();
This generates this SQL:
SELECT
(CASE WHEN Games.status = 'home_default'
THEN 'home_team_id' ELSE 'away_team_id' END) AS `id`,
COUNT(Games.id) AS `count`
FROM games Games
WHERE Games.status in ('home_default','away_default')
GROUP BY id
Note that THEN 'home_team_id' ELSE 'away_team_id' END should be simply THEN home_team_id ELSE away_team_id END. This will then allow me to read the list of ids of teams that have defaulted games along with the number of games they defaulted.

Answer 1

By default the values passed to the second argument of QueryExpression::addCase() are being treated as to be converted to literal values, not as identifiers. If you need the latter, then you should use an expression, an IdentifierExpression.
use Cake\Database\Expression\IdentifierExpression;
// ...
$team_id = $query->newExpr()->addCase(
[
$query->newExpr()->eq('Games.status', 'home_default')
],
[
new IdentifierExpression('Games.home_team_id'),
new IdentifierExpression('Games.away_team_id')
]
);
Also ditch the third argument in this case, you don't want the values to be string literals (for expressions the types would be ignored anyways).