SELECT data from 2 databases

[dragon52]

Hello,

I hope someone can help me!

I have 'payment' data in two databases. One db contains old/archived data. Each db contains the exact same table "PmtsTbl" but obviously the data is different.

I want to select all payment data from both db within a date range. I have the following sql which works in "Mysql Workbench"

SELECT * FROM 
(SELECT * FROM DB1.PmtsTbl where DB1.PmtsTbl.Date=x
UNION
SELECT * FROM DB2.PmtsTbl where DB2.PmtsTbl.Date=x)
RESULTS ORDER BY Date

Using PDO PHP I don't know how to combine the single SQL statement above with two PDO connection objects as show below.

$this->pdo = new PDO ("mysql:host=".DB_HOST.";dbname=".DB_1."; charset=utf8", DB_USER, DB_PASSWORD);
 
$this->pdo = new PDO ("mysql:host=".DB_HOST.";dbname=".DB_2.";charset=utf8", DB_USER, DB_PASSWORD);

How do I use PHP code like
$this->stmt = pdo->prepare($sql)

Thank you in advance