Parent-child sorting

Question

I am trying to sort a table that has parent- and child-rows. Sorting should always be performed based on the parent rows, but the childrows should always immediately follow the parent. Table data is in format of

[
{name: 'xxx', group: 'A', type: 'parent'},
{name: 'yyy', group: 'B', type: 'parent'},
{name: 'zzz', group: 'A', type: 'child'},
{name: 'qqq', group: 'A', type: 'child'}
]

So, sorted by name the correct order would be xxx,qqq,zzz,yyy.

The data comes from a Laravel/Eloquent ajax query and is displayed in a datatables table, so sorting it either client or server side would be fine.

Not related to multisort (comment below)

Answer 1

Use orderFixed option to always apply ordering to a certain column before/after any other columns.

For example:

var table = $('#example').DataTable({       
    ajax: {
       url:'https://api.myjson.com/bins/4n6ey',
       dataSrc: ''
    },
    orderFixed: {
       pre: [[1, 'asc'], [2, 'desc']]
    },
    columns: [
        { data: 'name' },
        { data: 'group' },
        { data: 'type'}
    ]
});

See this jsFiddle for code and demonstration.

Answer 2

Couldn't figure out how to do it in SQL, DataTables callbacks/sorters (although a plugin would be an workable option), Eloquent callbacks or Yajra DataTables adapter options. So I just went the brute force way.

1. sort by intended column using sql
2. separate master/child (debt/guarantee) lines

3. look up each child lines' master record for the correct sorting index and create a new indexing column for the "true" order

     $dataTable_column_map = $claimPortfolio->getColumnMap(); $claimPortfolioLines = $claimPortfolio->lines()->orderBy($dataTable_column_map[$request->get('order')[0]['column']]['name'], $request->get('order')[0]['dir'])->get(); $claimPortfolioLines = ClaimPortfolioService::orderGuarantees($claimPortfolioLines); $claimPortfolioLines = ClaimPortfolioService::filterLines($claimPortfolioLines, Input::get('search.value')); Session::put('claimPortfolioLineIdList', $claimPortfolioLines->lists('id')->toArray()); return Datatables::of($claimPortfolioLines) ->order(function() { return true; // cancel built-in ordering & filtering }) ->filter(function() { return true; }) ->make(true); public static function orderGuarantees(Collection $claimPortfolioLines) { $claimPortfolioLinesGuarantees = $claimPortfolioLines->filter(function ($claimPortfolioLine) { return $claimPortfolioLine->line_type == 'GUARANTEE'; }); $claimPortfolioLines = $claimPortfolioLines->filter(function ($claimPortfolioLine) { return $claimPortfolioLine->line_type == 'DEBT'; }); foreach ($claimPortfolioLines as $idx_line => $claimPortfolioLine) { $claimPortfolioLine->sortOrder = $idx_line; foreach ($claimPortfolioLinesGuarantees as $idx_guaranteeLine => $claimPortfolioLineGuarantee) { if ($claimPortfolioLineGuarantee->contract_no == $claimPortfolioLine->contract_no && $claimPortfolioLine->line_type == 'DEBT') { $claimPortfolioLineGuarantee->sortOrder = "{$idx_line}.{$idx_guaranteeLine}"; $claimPortfolioLines->push($claimPortfolioLineGuarantee); } } } $claimPortfolioLines = $claimPortfolioLines->sortBy('sortOrder'); return $claimPortfolioLines; } 

Answer 3

The general solution for this in SQL is to self join and order by multiple columns, including whether it's a parent. In OP's case, assuming a table of data d ( t an alias meaning table , and s meaning sort ):

SELECT t.*
FROM d AS t
INNER JOIN d AS s
    ON s.group = t.group
    AND t.type = 'parent'
ORDER BY s.name, t.type = 'parent' DESC, t.name