MySQL: joining two tables

Question

I have two tables in the database, one is transactions table:

id    mac            timestamp     siteid


1     C8BCC8BD7684   1365987620      5


2     8C2DAA4CB9E6   1365995414      4

another one is equipment_details table:

id       mac_address       organization 


1        00:00:0E          Fujitsu limited


2        00:00:00          Xerox corporation


3        C8:BC:C8          Apple, inc.


4        8C:2D:AA:         Apple, inc.

I need to join these two tables. So the output table should be like,

 id   mac            timestamp     siteid      organization

1     C8BCC8BD7684   1365987620      5         Apple, inc.


2     8C2DAA4CB9E6   1365995414      4         Apple, inc.

Can I use something like wordwrap(substr(transactions.mac, 0, 6),2,":",true) to retreive the first 6 letters from the transactions.mac? I have tried the below code, but I am getting mysql error:

"SELECT transactions.mac,equipment_details.mac_address,equipment_details.organization FROM `transactions`, `equipment_details` WHERE transactions.mac LIKE equipment_details.mac_address+'%' "

Any help much be appreciated!

Answer 1

SELECT  a.*,
        b.Organization
FROM    transactions a
        INNER JOIN equipment_details b
            ON SUBSTRING(a.mac, 1,6) = REPLACE(b.mac_address, ':', '')

• SQLFiddle Demo

OUTPUT

╔════╦══════════════╦════════════╦════════╦══════════════╗
║ ID ║     MAC      ║ TIMESTAMP  ║ SITEID ║ ORGANIZATION ║
╠════╬══════════════╬════════════╬════════╬══════════════╣
║  1 ║ C8BCC8BD7684 ║ 1365987620 ║      5 ║ Apple, inc.  ║
║  2 ║ 8C2DAA4CB9E6 ║ 1365995414 ║      4 ║ Apple, inc.  ║
╚════╩══════════════╩════════════╩════════╩══════════════╝

The only problem with this one is that it doesn't uses index and will perform very slow if you have large database. The best way you can do is to normalize properly the tables :)

Answer 2

Try like this

SELECT transactions.mac,equipment_details.mac_address,equipment_details.organization
FROM `transactions`
JOIN 'equipment_details'
ON equipment_details.mac_address = REPLACE(SUBSTRING('transactions.mac',6),":","")

you dont need like statement for this now...if you want to compare with LIKE then its syntax should be

WHERE transactions.mac LIKE equipment_details.mac_address = 'my_string%'

Answer 3

How about this?

SELECT tr.mac,ed.mac_address,ed.organization
FROM `transactions` tr
JOIN 'equipment_details' ed
ON ed.mac_address = REPLACE(SUBSTRING('tr.mac',6),":","")  

With Replace you can directly compare the mac address with the ":" and the ones with no ":"

hope it's helps.

Answer 4

You can Try this too. Inner Join may help you to join two tables. I guess your Primary key is 'id' in both tables & you've referenced 'id' as a foreign key in equipment_details table.

select tr.id,tr.mac,tr.timestamp,tr.siteid,ed.organisation from transactions tr inner join equipment_details ed ON ed.mac_address = SUBSTRING('transactions.mac',6) where tr.id = ed.id