codeigniter join 2 table data - php

Question

hi everyone i am new to codeigniter and currently working on a small project in the project i am trying to join two tables and display there data in single table. i looked at the user guide that codeigniter has an i am not sure how this work
$this->db->join();
what table should be first and what id key should be firs. Can someone explain me more in detail about this please use examples if u can. I am trying to join credential table and tblanswers. Tnx for answering.
i have tried to code a function using this example:
$this->db->select('*');
$this->db->from('blogs');
$this->db->join('comments', 'comments.id = blogs.id');
$query = $this->db->get();
EDIT:
instead of using join method in codeigniter is it possible to use a simple function to retrieve the two table data separately? all i want is to echo the data from database table on to a html table in my website page to be displayed is it possible to write two get functions to retrieve two tables separately ?

Answer 1

It doesn't matter what table is first... Simply:
<?php
$this->db->select('t1.name, t2.something, t3.another')
->from('table1 as t1')
->where('t1.id', $id)
->join('table2 as t2', 't1.id = t2.id', 'LEFT')
->join('table3 as t3', 't1.id = t3.id', 'LEFT')
->get();
?>

Answer 2

here is how it works:
suppose we have two tables namely student, library.
note: but remember that one of the column should match if you want to use where condition/ here we assume that both tables have std_id column
Write the the select query as follows, in the brackets write what are all the things you want
note:write as shown below don't put quotes to each single one put it on whole at once.
*note: suppose we want name, phone_no. from student table and book_name form library table.*
$this->db->select('name, phone_number, book_name');
Now write the from query and write one of the table name(No rule)
$this->db->from('student');
Now join this with the another table with join query
$this->db->join('library', 'students.std_id=library_std_id');
Now write the where condition that like you want book name form library table where std id=1(in practical you need to fetch this id from view/database)
$this->db->where('std_id', 1);
$q= $this->db->get();
That's it it's done now you can print and check the result.

Answer 3

$this->db->join('comments', 'comments.id = blogs.id');
With this line you tell: search me inside comments all comments with id equal blogs.id.
Usually is something like that I think:
$this->db->join('comments', 'comments.blogs_id = blogs.id');
You have to insert into your table a field named blogs_id (int value unisgned) because blogs can have more comments.
Isn't important the position of first or second value

Answer 4

Hi this will work for joining two tables in codeIgnator.
$this->db->select("chat.id,chat.name,chat.email,chat.phone,chat.date,post.post");
$this->db->from('chat');
$this->db->join('post', 'chat.id = post.id');
$query = $this->db->get();
if($query->num_rows() != 0)
{
return $query->result();
}
else
{
return false;
}
You can change to the query as you like do trail and error method to get your appropriate results.

Answer 5

This is my code for joint many tables as possible.
I have 3 tables professeurs,publications and support.
public function toutesdonnées(){
$this->db->select("*");
$this->db->from('publication');
$this->db->join('support', 'publication.idsup = support.idsup');
$this->db->join('professeurs', 'publication.emailprof = professeurs.emailprof');
$query = $this->db->get();
if($query->num_rows() != 0)
{
return $query->result();
}
else
{
return false;
}