system.db.runScalarPrepQuery(query, args, database, tx)
String query - A SQL query (typically a SELECT) to run as a prepared statement with placeholders (?) denoting where the arguments go, that should be designed to return one row and one column.
Object args - A list of arguments. Will be used in order to match each placeholder (?) found in the query.
String database - The name of the database connection to execute against. If omitted or "", the project's default database connection will be used.
String tx - A transaction identifier. If omitted, the query will be executed in its own transaction.
Object - The value from the first row and first column of the results. Returns None if no rows were returned.