Compare data from two different Bds

Question

Good morning, everyone,

I have the following scenario: BD1 from third parties where I can only perform queries. I created a web page to display BD1 data, in case it would be a table where I have a field with a combobox that I have some options to be selected.

Problem: I need to save the status of the combobox according to the table ID so that every time it is loaded it shows the information that was selected.

Trying: I created a BD2 local, to record the information in this case it records the BD1 ID and the selected option of the combobox, I thought to do an INNER JOIN between the banks but I did not find anything that can help me and also not sure if this would be the best solution.

Codes:

$q_db2 = $conn2->query("SELECT monitor.infos.iStatus, monitor.infos.iCliente FROM monitor.infos");

$data = array();   

while($rows2 = $q_db2->fetch_assoc()){

    $q_db1 = $conn->query("SELECT OS.OS, OS.DATA, OS.CONTRA, OS.TIPO, OS.EQUIPE, OS.TECNICO, OS.TECNICO_AUX1, OS.DTAGEN, OS.UF, EQ.NOME AS EQNOME, TP.NOME AS TPNOME, TC.NOME AS TCNOME, TCX.NOME AS TCXNOME 
    FROM dados.tva1710 AS OS 
    INNER JOIN dados.tva1800 AS EQ 
    ON EQ.CODIGO = OS.EQUIPE 
    INNER JOIN dados.at_os AS TP 
    ON TP.CODIGO = OS.TIPO 
    INNER JOIN dados.tva1900 AS TC 
    ON TC.CODIGO = OS.TECNICO 
    INNER JOIN dados.tva1900 AS TCX 
    ON TCX.CODIGO = OS.TECNICO_AUX1
    WHERE OS.DTAGEN != '0000-00-00' AND OS.DTAGEN > '2018-01-01' AND OS.UF = 'SP'");
    while($rows = $q_db1->fetch_assoc()){

       $arrayData = array();
       $arrayData[] = utf8_encode($rows['OS']);
       $arrayData[] = utf8_encode($rows2['iCliente']);
       $arrayData[] = utf8_encode($rows['CONTRA']);
       $arrayData[] = utf8_encode($rows['TPNOME']);
       $arrayData[] = utf8_encode($rows['EQNOME']);
       $arrayData[] = utf8_encode($rows['TCNOME']);
       $arrayData[] = utf8_encode($rows['TCXNOME']);
       $arrayData[] = utf8_encode($rows['DTAGEN']);
       $arrayData[] = utf8_encode($rows2['iStatus']);

       $data[] = $arrayData;         
 }  
}
 $results = array(
"sEcho" => 1,
"iTotalRecords" => count($data),
"iTotalDisplayRecords" => count($data),
"aaData" => $data);

echo json_encode($results, JSON_UNESCAPED_UNICODE)  ;
exit;

I tried to create a Where by matching the BD1 ID field with the BD2 ID field but it returned me only the data that was recorded, so it didn’t work either.

 WHERE OS.DTAGEN != '0000-00-00' AND OS.DTAGEN > '2018-01-01' AND OS.UF = 'SP' AND OS.OS = '{$rows2['iCliente']}'");