MySQL: 4 Table "has-many-through" Join?

Posted by Nebs on Stack Overflow See other posts from Stack Overflow or by Nebs
Published on 2010-04-14T19:57:09Z Indexed on 2010/04/14 20:03 UTC
Read the original article Hit count: 200

Filed under:

mysql

|

join

|

has-many-through

|

php

Let's say I have the following 4 tables (for examples' sake): Owners, Trucks, Boxes, Apples.

An owner can have many trucks, a truck can have many boxes and a box can have many apples.

Owners have an id. Trucks have an id and owner_id. Boxes have an id and truck_id. Apples have an id and box_id.

Let's say I want to get all the apples "owned" by an owner with id = 34. So I want to get all the boxes that are in boxes that are in trucks that owner 34 owns.

There is a "hierarchy" if you will of 4 tables that each only has reference to its direct "parent". How can I quickly filter boxes while satisfying conditions across the other 3 tables?

I hope that made sense somewhat.

Thanks.

© Stack Overflow or respective owner

Related posts about mysql

How to remove MySQL completely with config and library files on ubuntu 12.04 gnome 3.0

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I tried everything till now: sudo apt-get remove mysql-server mysql-client mysql-common sudo apt-get purge mysql-server mysql-client mysql-common sudo apt-get autoremove and even more commands... But whenever I am trying to locate mysql. I get a no. of files related to mysql command: shell>>… >>> More
mysql: Cannot load from mysql.proc. The table is probably corrupted

as seen on Server Fault - Search for 'Server Fault'
Mysql was started: /usr/bin/mysqld_safe --datadir=/srv/mysql/myDB --log-error=/srv/mysql/logs/mysqld-myDB.log --pid-file=/srv/mysql/pids/mysqld-myDB.pid --user=mysql --socket=/srv/mysql/sockets/mysql-myDB.sock --port=3700 but when I'm trying to do something: ERROR 1548 (HY000) at line 1: Cannot… >>> More
Why is there a /etc/init.d/mysql file on this Slackware machine? How could it have gotten there?

as seen on Server Fault - Search for 'Server Fault'
A client of my IT-consulting service owns a web-development shop. He's been having problems with a Slackware 12.0 server running MySQL 5.0.67. The machine was set up by the client's sysadmin, who left on bad terms. My client no longer employs a sysadmin. As far as I can tell, the only copy of MySQL… >>> More
mysql: Bind on unix socket: Permission denied

as seen on Server Fault - Search for 'Server Fault'
Can't start mysql with: sudo /usr/bin/mysqld_safe --datadir=/srv/mysql/myDB --log-error=/srv/mysql/logs/mysqld-myDB.log --pid-file=/srv/mysql/pids/mysqld-myDB.pid --user=mysql --socket=/srv/mysql/sockets/mysql-myDB.sock --port=3700 120222 13:40:48 mysqld_safe Starting mysqld daemon with databases… >>> More
MySQL – Learning MySQL Online in 6 Hours – MySQL Fundamentals in 320 Minutes

as seen on SQL Authority - Search for 'SQL Authority'
MySQL is one of the most popular database language and I have been recently working with it a lot. Data have no barrier and every database have their own place. I have been working with MySQL for quite a while and just like SQL Server, I often find lots of people asking me if I have a tutorial which… >>> More

Related posts about join

Improving Partitioned Table Join Performance

as seen on SQL Blog - Search for 'SQL Blog'
The query optimizer does not always choose an optimal strategy when joining partitioned tables. This post looks at an example, showing how a manual rewrite of the query can almost double performance, while reducing the memory grant to almost nothing. Test Data The two tables in this example use… >>> More
MS SQL 2008, join or no join?

as seen on Stack Overflow - Search for 'Stack Overflow'
Just a small question regarding joins. I have a table with around 30 fields and i was thinking about making a second table to store 10 of those fields. Then i would just join them in with the main data. The 10 fields that i was planning to store in a second table does not get queried directly, it's… >>> More
SQL Server 2008, join or no join?

as seen on Stack Overflow - Search for 'Stack Overflow'
Just a small question regarding joins. I have a table with around 30 fields and i was thinking about making a second table to store 10 of those fields. Then i would just join them in with the main data. The 10 fields that i was planning to store in a second table does not get queried directly, it's… >>> More
Simple join gives unnecessary rows,How to get join properly with only matches in both tables

as seen on Stack Overflow - Search for 'Stack Overflow'
Table 1 Field1 Field2 AA 20 AA 20 AB 12 AC 13 Table2 field3 field4 AA 20 AA 20 AC 13 AD 23 AW 21 output required: newfield field2 field4 AA 20 20 AA 20 20 AC 13 13 I used: select field1 as newfield, t1.field2,t2.field4 from table1 t1 join table2 t2 on t1.field1=t2.field3 This… >>> More
Mulitple full joins in Postgres is slow

as seen on Stack Overflow - Search for 'Stack Overflow'
I have a program to use the IMDB database and am having very slow performance on my query. It appears that it doesn't use my where condition until after it materializes everything. I looked around for hints to use but nothing seems to work. Here is my query: SELECT * FROM name as n1 FULL JOIN… >>> More