MySQL非常简单的连接示例请求子表

Question

I keep falling back into questions with MySQL joining. And I would like to request a very simple example I could use to continue my journey of understanding learning the MySQL syntax.

Let's say I got the following table's

test_testtable

• testtable_id
• testtable_name
• testtable_user
• testtable_option
• testtable_textfield

test_testlink

• testlink_id
• testlink_link
• testlink_address

test_address

• address_id
• address_name
• address_phone
• address_email
• address_street
• address_city
• address_zip

I would like to make a selection like :

SELECT * (lets say I would define the fields) FROM `test_testable` 
JOIN `test_testtable`.`testtable_id` = `test_testlink`.`testlink_link`
AND
JOIN `test_testlink`.`testlink_addres` = `test_address`.`address_id`
WHERE `user_id` = 5

Hence the linking structure is like:

test_testtable.testtable_id = leading

table test_testlink is a table to link the table test_testtable and test_address

And linking table test_testlink uses the field testlink_link to link to the table test_testtable, and uses the field testlink_address to link to the table test_address

This does not work. FOR ME.. Since I continuously seem to fail of catching the correct syntax logic.

So I hope that someone could give me a small example of how to correctly implement such a simple yet critical query!

TIAD!!

Answer 1

A general approach :

SELECT table1.* FROM table1
JOIN table2 ON table2.id_table1 = table1.id
JOIN table3 ON table3.id_table2 = table2.id
WHERE table1.id = 10

For your purpose :

SELECT * (lets say I would define the fields) FROM `test_testable` 
JOIN `test_testlink` ON `test_testtable`.`testtable_id` = `test_testlink`.`testlink_link`
JOIN `test_address` ON `test_testlink`.`testlink_addres` = `test_address`.`address_id`
WHERE `user_id` = 5

Please read the reference