Datatables + PHP: Server-Side Processing on Multiple Tables

Question

How can I get Datatables Server-Side Processing script to work with a custom query? I need to select columns from multiple tables and have Datatables render them.

Datatables.net's Server-Side Processing (SSP) with PHP is summarized here: https://datatables.net/examples/server_side/simple.html

I found this SO question, but the original poster never provided his solution. I don't have sufficient reputation to ask him to provide more detail.

Here is my raw SQL without using Datatable's SSP

SELECT tbl_houses.style, tbl_houses.roomCount, tbl_residents.firstName, tbl_residents.lastName
FROM tbl_houses, tbl_residents
WHERE tbl_houses.houseID = tbl_residents.residentID

/* 
* # Equivalent query using JOIN suggested by @KumarRakesh
* # Note: JOIN ... ON is a synonym for INNER JOIN ... ON
* # Using JOIN conforms to syntax spec'd by ANSI-92 https://stackoverflow.com/a/894855/946957
*
* SELECT tbl_houses.style, tbl_houses.roomCount, tbl_residents.firstName, tbl_residents.lastName 
* FROM tbl_houses 
* JOIN tbl_residents ON tbl_houses.houseID = tbl_residents.residentID
*/

How can I get Datatables to run queries off the above using SSP?

It appears server_processing.php only accepts 1 table and no custom filtering (i.e., WHERE clauses).

// DB table to use
$table = 'datatables_demo';

// Table's primary key
$primaryKey = 'id';

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * If you just want to use the basic configuration for DataTables with PHP
 * server-side, there is no need to edit below this line.
 */

require( 'ssp.class.php' );

echo json_encode(
    SSP::simple( $_GET, $sql_details, $table, $primaryKey, $columns )
);

However, ssp.class.php does support filtering using WHERE. I'm thinking I need to modify ssp.class.php to force in my WHERE clause

UPDATE

Found a solution. Will post when I have free time.

Solution 1

TL;DR: I ended up using a modification of the original Datatables ssp.class.php called ssp.php implemented by Emran Ul Hadi: https://github.com/emran/ssp

His modification accepts JOIN, WHERE, GROUP BY and column aliases. Although the file hasn't been updated in over a year, it still works with DataTables 1.12.x. I made some modifications to his version that increases its robustness and improves the documentation with clearer examples.

Will post my mods/updates here when I have a bit more time. Eventually I hope to put in a pull-request to get my updates into his repository.

Solution 2

SOLUTION

Class ssp.class.php doesn't support joins and sub-queries, but there is a workaround. The trick is to use sub-query as shown below in $table definition. Replace table with your actual table name in the sub-query.

$table = <<<EOT
 (
    SELECT 
      a.id, 
      a.name, 
      a.father_id, 
      b.name AS father_name
    FROM table a
    LEFT JOIN table b ON a.father_id = b.id
 ) temp
EOT;

$primaryKey = 'id';

$columns = array(
   array( 'db' => 'id',          'dt' => 0 ),
   array( 'db' => 'name',        'dt' => 1 ),
   array( 'db' => 'father_id',   'dt' => 2 ),
   array( 'db' => 'father_name', 'dt' => 3 )
);

$sql_details = array(
   'user' => '',
   'pass' => '',
   'db'   => '',
   'host' => ''
);

require( 'ssp.class.php' );
echo json_encode(
   SSP::simple( $_GET, $sql_details, $table, $primaryKey, $columns )
);

You also need to edit ssp.class.php and replace all instances of FROM `$table` with FROM $table to remove backticks.

Make sure all column names are unique otherwise use AS to assign an alias.

NOTES

There is also github.com/emran/ssp repository that contains enhanced ssp.class.php supporting JOINs.

LINKS

See jQuery DataTables: Using WHERE, JOIN and GROUP BY with ssp.class.php for more information.

Solution 3

It looks like the scripts from DataTables are indeed not designed for your particular use case. But there is a method that allows for custom where clauses and from reading the source of ssp.class.php#complex I think that this configuration should work for your by using the WHERE method. The JOIN method will not work here.

Long story short: edit your server_processing.php to that:

<?php
// DB table to use
$table = 'tbl_houses, tbl_residents';

// First table's primary key
$primaryKey = 'tbl_houses.id';

$columns = [
    [ 'db' => 'tbl_houses.style'],
    [ 'db' => 'bl_houses.roomCount'],
    [ 'db' => 'tbl_residents.firstName'],
    [ 'db' => 'tbl_residents.lastName']

);

// connection details
$sql_details = [

];

$whereAll = 'tbl_houses.houseID = tbl_residents.residentID';

require( 'ssp.class.php' );

echo json_encode(
    SSP::complex( $_GET, $sql_details, $table, $primaryKey, $columns , null, $whereAll);
);

The complex method accepts your custom WHERE clause. But the tricky thing is the usage of 2 tables. This is what the script does not seem to be designed for. I took a look on how it is building the final sql query and it appears that you may just use this table_name.field_name notation in the config, as well as the table_name, table_name notation for the $table and $primaryKey variables.

As mentioned, the usage of 2 tables is not intended by the DataTables script. I don't know if all features of DataTables will work with that.

Comments

[Kumar Rakesh]

You can also do it .. with SELECT tbl_house.style, tbl_house.roomCount, tbl_residents.firstName, tbl_residents.lastName FROM tbl_house JOIN tbl_resident ON tbl_house.houseID = tbl_resident.residentID

[Christian]

Thanks for the deep dive! I implemented your suggestion and you are correct! The datatables ssp.class.php does not support multiple tables out-of-the-box. That is, $table = 'tbl_houses, tbl_residents' produces a Base table or view not found: 1146 error. However, I did find a solution and will post when I have a free minute.

[Milson]

Have you tried to modify it for supporting "UNION ALL"?

[Christian]

@Milson been meaning to post a draft up to Github with a pull-request to Emran. My mods were mainly simplification of syntax used to call ssp functions/procedures and documentation clarity. Adding UNION functionality should be trivial. Taking a look at the changes Emran made to turn on JOIN gives context on how to implement other SQL functions