It appears the class constants only cover PDO::PARAM_BOOL, PDO::PARAM_INT and PDO::PARAM_STR for binding. Do you just bind decimal / f
You have to use PDO::PARAM_STR, but for SQLite and other engines this can have unpredictable behaviors. See this issue for one example: SQLite HAVING comparison error
AFAIK PDO::PARAM_STR is the way to go.
If you really want to use PDO you'll have to enter it as an PARAM_INT, but I never use a specification for double.
It is an optional parameter to specify the PDO type.
I guess you would better not set the PDO type for doubles.