I need to make a query using 3 tables and i having some trouble with that.
I have 3 tables in my project:
projects, projects_categories and categories
projects
id_project
title
date
projects_categories
id_proj_cat
id_project
id_category
categories
id_category
name
I already made a join query but the result is a array with the same project_id showing several times.
What i need is a more efficient query that can list for each project_id a array inside, with it´s categories and names. Something like that.
I can make a separate query but im trying to achieve that in one single query.
Try this
$this->db->from("projects p");
$this->db->select("p.id_project,c.categories,c.name");
$this->db->join("projects_categories pc","pc.id_project = p.id_project","LEFT");
$this->db->join("categories c","c.id_category = pc.id_category","LEFT");
$result=$this->db->get()->result_array();
Now $result is your array.
Try this one:
$this->db->select('p.id_project,c.categories,c.name');
$this->db->from('projects p');
$this->db->join("projects_categories pc","p.id_project = pc.id_project","INNER");
$this->db->join("categories c","pc.id_category = c.id_category","INNER");
$query = $this->db->get();
return $query->result_array();
Related
"Table1":
id
name
1
Ulrich
2
Stern
"Table2":
id
school
tid
1
A
1
2
B
1
I want to join 2 table to get all information. With SQL query like this:
SELECT Table1.id,
name,
school
FROM `Table1`
INNER JOIN `Table2`
ON Table1.id = Table2.tid
It gives me all information as I expect (I mean 2 rows with name 'Ulrich').
But when I do with Yii2 query:
$query = self::find();
$query -> alias('t1')
-> innerJoin(['t2'=>'Table2'], 't1.id=t2.tid')
$result = NULL;
if($total = $query->count()) {
$result = $query
-> select([t1.*, t2.school])
->asArray()
->all()
;
$result[0]['count'] = $total;
}
it only gives me 1 row with name 'Ulirch'.
Can anyone help me with this problem. Thank you very much.
If you use ActiveRecord::find() method to create query you will get instance of yii\db\ActiveQuery. This is query designed to load ActiveRecord models. Because of that if you do any type of join and your result set contains primary key of your main model (The model which find() method was called to create query) the ActiveQuery will remove any rows it considers duplicate.
The duplicates are recognised based on main model primary key so the rows in resultset will be considered duplicate even if the data from joined table are different. That's exactly what happened in your case.
To avoid that you have to use query builder instead of ActiveQuery.
Your query can look for example like this:
$query = (new \yii\db\Query())
->from(['t1' => self::tableName()])
->innerJoin(['t2'=>'Table2'], 't1.id=t2.tid');
Ok, so, my problem is I have a table with posts, each post has a category id but not the category name. i have another table of category id's with the category name. so i want to loop through the posts and echo the category name. I was thinking I'd just put another mysqli query inside the while loop so
while($row_post = mysqli_fetch_array($result_post)){
query_post_cat = "SELECT category_name FROM categories WHERE category_id = " . $row_post["category_id"];
result_post_cat = mysqli_query($link, $query_post_cat);
$category_name = something here not sure
echo $row_post["post_title"] . $category_name;
}
Can't figure out where to go from there. The other way I thought is to do the category table outside the while loop and somehow make an assoc array with the cat id as the key and cat name as the value and just echo
category_name[$row_post["category_id"]]
etc in the while loop.
Aside from this I'm pretty sure the way I'm using mysqli is not ideal, when I see other peoples code it seems they are using the -> object operator a lot and I have no idea what that is or how it works and cant find any information on it. So I'm pretty lost as you can see
Thanks your help
If you run a query with a join, you can get the data from both tables at once, like this:
SELECT post_table.*, categories.category_name FROM post_table INNER JOIN categories ON post_table.category_id = categories.category_id;
You can look up more on this at: http://www.w3schools.com/sql/sql_join.asp
Your code should be as below:-
while($row_post = mysqli_fetch_array($result_post)){
// missed $ below line
$query_post_cat = "SELECT category_name FROM categories WHERE category_id = {$row_post['category_id']}";
$result_post_cat = mysqli_query($link, $query_post_cat);
// use mysqli_fetch_row below
$category_name = mysqli_fetch_row($result_post_cat));
echo $row_post["post_title"] . $category_name;
}
Better way is to use mysql JOIN in your query to get desired records in single shot.
can you help I have two tables images and note. I would like to get all items from these tables and order by date. It is possible I am using active record in codeigniter. Tables are independent.
Thank you for replies.
this should work:
$this->db->orderby("date", "ASC"); //or desc
$query = $this->db->get('images'); //or $query = $this->db->get('note');
$result=$query->result_array();
print_r($result);
or if you want use union all
$this->db->query('SELECT * FROM (SELECT id, date FROM images UNION ALL SELECT id, date FROM note) result ORDER BY result.date');
Notice that each SELECT statement within the UNION must have the same number of columns. The columns must also have similar data types. Also, the columns in each SELECT statement must be in the same order from http://www.w3schools.com/sql/sql_union.asp.
I think you want a Cross Join.
Here is your codeigniter code
$this->db->from("images ,note");
$this->db->select("images.*,note.*);
//make sure both dont have same column name other wise use this
//$this->db->select("images.column1,images.column2,note.column1);
$this->db->orderby("images.date", "DESC");
//you can add more orderby
//you can add where condition too
$result=$this->db->get()->result_array();
Now you will get the cross product.
Hope it will help you.
In which table do you have date column? I assume you have it in images table.
$this->db->select('images.coulmn1, images.culmn2, images.date_col, note.col1, note.col2');
$this->db->from('images');
$this->db->join('note', 'note.key1 = images.key1); //key1 is key field to relate both table.
$this->db->order_by("images.date_col", "desc");
$result = $this->db->get()->result_array();
Hope it will help.
Try this:
$this->db->select('*');
$this->db->from('images');
$this->db->join('note');
$this->db->orderby("date column name", "ASC");
$query = $this->db->get();
$result=$query->result_array();
print_r($result);
I am learning how to work with MySQL, and at the moment I succeed to show data from my table, using:
while($objResult2 = mysqli_fetch_assoc($objQuery_product)) {
Results are shown by using this variable $objResult2["id_product"]; this way i can take from DB any field I want like: $objResult2["name"]; $objResult2["email"]; etc.
But what i do if i have in the table more rows with the same id_product?
I want to write a if statment, which counts if id_product repeats. How to do that? If it is a lot of work, atleast please give me an idea of the right tutorial that I must read. Because i am trying second day to fix this, and searched google but i didnt find what i need, or maybe i coulndt understand it....
This is my query
$sql_product = "SELECT * FROM ps_product AS prod";
$join_product = " LEFT JOIN ps_product_lang AS lang ON lang.id_product = prod.id_product";
$join2_product = " LEFT JOIN ps_stock_available AS stok ON stok.id_product = prod.id_product";
$where_product =" WHERE prod.id_category_default = $idp AND lang.id_lang = 8";
$sql_product = $sql_product.$join_product.$join2_product.$where_product;
$objQuery_product = mysqli_query($objConnect, $sql_product) or die ("Error Query [".$sql_product."]");
You can simple remove the same id_product using DISTINCT keyword in your query. Such as:
SELECT DISTINCT id_product FROM my_table
This will give you results with different ids only.
The second way of doing it is taking the output values inside an array.
In your while loop:
$my_array[] = $objResult2["id_product"];
Then using array_filter remove all the duplicates inside the array.
YOu can also use array_count_values() if you want to count the duplicate values.
Ok here we go. For example you are fetching data with this query.
select id_product, name from PRODUCTS;
Suppose above query gives you 5 records.
id_product name
1 bat
2 hockey
2 hockey
3 shoes
4 gloves
Now you got 2,2 and hockey, hockey. Instead of thinking this way that you have to introduce an if statement to filter repeating records or same name or id_product records.
Rewrite your sql query like this.
select distinct id_product, name from PRODUCTS;
Or if you need count of each then my friend you will write your query something like this...
Graham Ritchie, if Andrei needs count of each repeating record then we will do something like this in our query.
SELECT PRODUCT_ID,
COUNT(PRODUCT_ID) AS Num_Of_Occurrences
FROM PRODUCTS
GROUP BY PRODUCT_ID
HAVING ( COUNT(PRODUCT_ID) > 1 );
SELECT id_product,COUNT(*) AS count
FROM tablename
GROUP BY id_product;
This query will then return you two items in your query
$objResult2["id_product"] //and
$objResult2["count"]
The if statement is then just
if($objResult2["count"] > 1){
//Do whatever you want to do with items with more than 1 occurence.
//for this example we will echo out all of the `product_id` that occur more than once.
echo $objResult2["id_product"] . " occurs more than once in the database<br/>";
}
I have two tables 'accounts_transactions' and 'accounts_bills_transactions'.
I have to left join these two using active record of codeigniter.But the names of key columns used to join are different.So I am not getting the key column from the left table in the output .What query should I write to get the key column from the left table included in the result.
My code is
$this->db->select('*');
$this->db->from('accounts_transactions');
$this->db->join('accounts_bills_transactions', 'accounts_transactions.id = accounts_bills_transactions.transaction_id','left');
$query = $this->db->get();
So, as you see the key columns used to join here are , id from left table and transaction_id from second table.The problem is that I am not getting the id from left table in the result.But I am getting all other columns.I assume the problem is because of difference in column names used to join.ie both the column names are not named 'id' .So how can I get the id from left table included in the result.
You could alias them:
$this->db->select('accounts_transatctions.*, account_transactions.id AS a_id,
accounts_bills_transactions.*,
account_bills_transactions.id AS ab_id');
$this->db->from('accounts_transactions');
$this->db->join('accounts_bills_transactions', 'accounts_transactions.id = accounts_transactions.transaction_id','left');
$query = $this->db->get();
The two IDs will now be available as a_id and ab_id (or whatever alias you choose)
Note: I'm not sure if you can alias in AR without avoiding escaping (haven't been using CI for a while). Should you get any error for that reason, just pass false as second parameter of $this->db->select():
$this->db->select('...', false);
you can try this if you confuse of using $this->where or $this->join
$query = $this->db->query("select ......");
return $query;
You problem is so simple. You can use this query
$query = $this->db
->select('at.*')
->select('abt.id as abt_id');
->from('accounts_transactions at');
->join('accounts_bills_transactions abt', 'at.id = abt.transaction_id','left');
->get()
->result();
When same column are used in join it selects only one. You need to give alise to the other column in second table. The best practice is to use a structure like this
accounts_transatctions
--------------------------
accounts_transatctions_id
other_columns
accounts_bills_transactions
---------------------------
accounts_bills_transactions_id
accounts_transatctions_id
other_columns