I am trying to create a new table that will consist of selected data from three existing tables.
The three existing tables are set up as following, and my desired result is at the bottom:
people
id last_name first_name email
1 Smith Fred Fred@..
2 Jones Tom Tom@..
3 Doe Jane Jane@..
taxonomy
id taxonomy
1 age
2 gender
3 height
details
id person_id detail_id content
1 1 1 36
2 1 2 M
3 1 3 5'10"
4 2 1 29
5 2 2 M
6 2 3 6'3"
7 3 1 27
8 3 2 F
9 3 3 5'8"
New Table
id last_name first_name email age
1 Smith Fred Fred@.. 36
2 Jones Tom Tom@.. 29
3 Doe Jane Jane@.. 27
Thanks in advance for your help!
You need to do a 3-way JOIN:
CREATE TABLE new_table AS
SELECT p.*, d.content AS age
FROM people AS p
JOIN details AS d ON d.person_id = p.id
JOIN taxonomy AS t ON t.id = d.detail_id
WHERE t.taxonomy = 'age'
Or if you've already created the table, you can do:
INSERT INTO new_table (id, last_name, first_name, email, age)
SELECT p.id, p.last_name, p.first_name, p.email, d.content AS age
FROM people AS p
JOIN details AS d ON d.person_id = p.id
JOIN taxonomy AS t ON t.id = d.detail_id
WHERE t.taxonomy = 'age'
To get multiple attributes, you have to join with the details and taxonomy tables separately for each attribute:
CREATE TABLE new_table AS
SELECT p.*, d1.content AS age, d2.content AS gender, d3.content AS height
FROM people AS p
JOIN details AS d1 ON d1.person_id = p.id
JOIN taxonomy AS t1 ON t1.id = d1.detail_id
JOIN details AS d2 ON d2.person_id = p.id
JOIN taxonomy AS t2 ON t2.id = d2.detail_id
JOIN details AS d3 ON d3.person_id = p.id
JOIN taxonomy AS t3 ON t3.id = d3.detail_id
WHERE t1.taxonomy = 'age' AND t2.taxonomy = 'gender' AND t3.taxonomy = 'height'
来源：https://stackoverflow.com/questions/26665499/mysql-create-a-new-table-using-data-and-columns-from-three-tables