Multiple Database Query MYSQL

Question

I have two databases, database A and B which each have a table named general_table. How can I write a query that will do a cross search on both general_tables depending on Barcode Number (Each table contains Barcode Number) with connection:

$connect = mysqli_connect('localhost', 'pharmana_general', '123456', 'A');

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Then just write the query as normal but prefix the table names with the database name. `database.table.column` — Patrick Q, Sep 29 '17 at 14:42
SELECT * FROM `pharmana_Hareket_db`.`general_Table` HDB, `pharmana_urun_db`.`general_Table` UDB Where HDB.EczaneID = '101' AND HDB.Yil = '2017' AND HDB.Barkod = UDB.Barkod Group by UDB.Ana_Kategori gives me unknow field Ana_Kategori error but i have that field — shiv zuh, Sep 29 '17 at 14:46
Please do not dump code in commments, it is unreadable. Edit your original question to add any new information. — Jay Blanchard, Sep 29 '17 at 14:51
Possible duplicate of [How do I construct a cross database query in PHP?](https://stackoverflow.com/questions/1999235/how-do-i-construct-a-cross-database-query-in-php) — Alex Blex, Sep 29 '17 at 16:39

score 1 · Accepted Answer · answered Sep 29 '17 at 14:57

It sounds like, based on what you're trying, the best solution would be a union:

SELECT a.* FROM pharmana_Hareket_db.`general_Table` a 
UNION
SELECT b.* FROM pharmana_urun_db.`general_Table` b

Building on the above example, you could do:

SELECT a.* FROM pharmana_Hareket_db.`general_Table` a 
WHERE a.barCodeField = 1234567980
UNION
SELECT b.* FROM pharmana_urun_db.`general_Table` b
WHERE b.barCodeField = 1234567980

You could of course a use JOIN, depending on the data set up, but it sounds like a UNION would work for you.

Edit: I have just read that you want both, so you could try a join

SELECT * FROM pharmana_Hareket_db.`general_Table` a 
INNER JOIN pharmana_urun_db.`general_Table` b
ON a.barCodeField = b.barCodeField

...which should only return rows that have matching barcodes in both DBs

Multiple Database Query MYSQL

1 Answers1