Need support with mySQL PDO JOIN statements - mysql

Question

I need an SELECT with JOIN but have at this moment no idea how to do this. I read already a few tutorials but it does not help me with my problem.
I have 2 tables in 2 databases:
DATABASE A
-> CONTENT
--> | PARTNERID | PAYSITE |
--> | 1 | siteA.com |
--> | 2 | siteA.com |
--> | 3 | siteA.com |
--> | 3 | siteB.com |
DATABASE B
-> WMIDPP
--> | WMID | PARTNERID | PARTNERURL | PAYSITE | ACTIVE
--> | 1 | 1 | AFFLINK 1 | siteA.com | 1
--> | 1 | 2 | AFFLINK 2 | siteA.com | 1
--> | 2 | 1 | AFFLINK 1 | siteA.com | 1
The above tables contains more fields, but with these fields I need to work with.
I know already the variables $WMID and $PAYSITE if I enter the website. When I enter the website, it should be show only the following data:
The complete data from table CONTENT and the field PARTNERURL from table WMIDPP when
CONTENT.PARTNERID = WMIDPP.PARTNERID
and
WMIDPP.WMID = $WMID
and
WMIDPP.PAYISTE = $PAYSITE
but only if
WMIDPP.ACTIVE = 1
Can anybody help with my problem?
Thanks in advance
Torsten
EDIT:
Here a little bit more information about the databases and tables:
Table CONTENT is located in DATABASE A and table WMIDPP is located in DATABASE B.
I access to these databases like this:
$DB_HOST = "localhost";
$DB_NAME1 = "database1";
$DB_NAME2 = "database2";
$DB_USER = "username";
$DB_PASS = "password";
$OPTION = array(PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES utf8");
try {
$dbAS = new PDO("mysql:host=" . $DB_HOST . ";dbname=" . $DB_NAME1, $DB_USER, $DB_PASS, $OPTION);
$dbEC = new PDO("mysql:host=" . $DB_HOST . ";dbname=" . $DB_NAME2, $DB_USER, $DB_PASS, $OPTION);
}
catch (PDOException $e) { exit("Verbindung fehlgeschlagen! " . $e->getMessage()); }
User has permissions to access to both databases.
I have 2 different databases, because there are 2 different projects. If it not work with these configuration, I can move the table(s) from DATABASE B to DATABASE A - but this should only the worst case option. I prefer a solution to merge the data of the tables in 2 different databases.

Answer 1

You use One PDO connection.
The signon details must allow access to both databases you want to access.
The full 'path' to any column is:
<database name> . <table name> . <column name>.
Here is tested code that joins tables from two separate databases.
Database 1) is called: 'testmysql'
Database 2) is called: 'rags1'
They are just databases i have setup here with similar structured tables on them.
Join two tables from separate databases
/* --------------------------------------------------------------------
* Query testmysql and rags1
*/
$sqlTest = 'SELECT rags1.user.id as RagsRowId,
rags1.user.userid as RagsUserId,
testmysql.customer.id as TestRowId,
testmysql.customer.custid as TestCustId,
testmysql.customer.address as TestCustAddress
FROM testmysql.customer
JOIN rags1.user
ON testmysql.customer.custid = rags1.user.userid
AND testmysql.customer.custid = :testCustId';
$stmt = $dbTest->prepare($sqlTest);
$stmt->bindValue(':testCustId', 'rfv123', PDO::PARAM_STR);
$stmt->execute();
$testResult = $stmt->fetchAll();
$stmt->closeCursor();
echo '<pre>';
print_r($testResult);
echo '<pre>';
Connection Details:
/**
* Two databases :
* 1) testmysql
* 2) rags1
*
* Use the 'database' name that you want to refer to in the queries.
*/
/**
* must have access rights to both db's
*/
// db connection to TestMysql and Rags1
$dsn = 'mysql:host=localhost;dbname=testmysql';
$username = 'rfv123';
$password = 'rfv123';
$options = array(
PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES utf8',
);
$dbTest = new PDO($dsn, $username, $password, $options);
$dbTest->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
Output:
Array
(
[0] => Array
(
[RagsRowId] => 1
[0] => 1
[RagsUserId] => rfv123
[1] => rfv123
[TestRowId] => 3
[2] => 3
[TestCustId] => rfv123
[3] => rfv123
[TestCustAddress] => 123 Somewhere Street, Cheshire
[4] => 123 Somewhere Street, Cheshire
)
)