mysql - query three tables
I have a relational database with three tables. The first containts id's that relate to the second. The second contains id's that relate to the third. The third contains the results I am after.
Is it possible with a single query to query an id in the first table which gives all results from the开发者_Go百科 third table that relate to it?
Sorry I am new to mySQL.
Mysql Join
Try this
select * from table1 t1
join table2 t2 on t1.t2ref = t2.id
join table3 t3 on t2.t3ref = t3.id
Add a where clause to search for certain rows in table1
where t1.field = 'value'
yes
SELECT t3.*
FROM t1, t2, t3
WHERE t1.id = t2.id
AND t2.otherid = t3.id
AND t1.id = XXXX
you want to use a join:
SELECT `t3`.`id`
FROM `table3` `t3`
LEFT JOIN `table2` `t2`
ON `t3`.`foreign_id` = `t2`.`id`
LEFT JOIN `table1` `t1`
ON `t2`.`foreign_id` = `t1`.`id`
WHERE `t1`.`id` = 'some_id'
Use the JOIN command to link your tables to oneantother.
Additionally I'd recommend this tutorial by Keith Brown.
You want to do a join. There is a lot of tutorials about this and various ways of doing it.
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