PHP processing data and create array - php

Question

I have a mysql query with result like this:
ID | index | Mapping index | Date
1 | 27 | value27 | 2019-04
2 | 28 | value28 | 2019-05
3 | 28 | value28 | 2019-05
4 | 32 | value32 | 2019-07
5 | 32 | value32 | 2019-05
The results should be prepared to display stacked charts. As result i need in php:
// array to display google chart
['2019-04', 1, 0, 0,],
['2019-05', 0, 2, 1,],
['2019-07', 0, 0, 1,],
// explanation
ID | value27 | value28 | value 32 | Date
1 | 1 | 0 | 0 | 2019-04
2 | 0 | 2 | 1 | 2019-05
2 | 0 | 0 | 1 | 2019-07
This is my php script:
$preparevar = array();
foreach($data["timechart"] as $date){
array_push($preparevar,[$date->date, $date->count , '\''.$date->repcontent.'\'' ]);
}
$googleChartArray = array(); //Use this array to group the results using date.
foreach( $preparevar as $d ) {
$date = $d[0];
$value = $d[1];
if( !isset( $googleChartArray[$date] ) ) {
$googleChartArray[$date] = array( "'". $date. "'" ); //Date needs to be enclosed in quote.
}
$googleChartArray[$date][] = $value;
}
$f = array(); //Format the above array to split value in a comma separated format.
foreach( $googleChartArray as $g ) {
$f[] = implode( ',' , $g );
}
$json_out = json_encode(array_values($googleChartArray));
The problem with this format is, that the zero values will be ignored:
[
['2019-04',1],
['2019-05',2,1],
['2019-07',1]
]
should be:
[
['2019-04',1,0,0],
['2019-05',0,2,1],
['2019-07',0,0,1]
]
Here an example of $data["timechart"]:
array(11) {
[0]=>
object(stdClass)#43 (14) {
["id"]=>
string(2) "46"
["index"]=>
string(2) "31"
["index2"]=>
string(1) "0"
["keynr"]=>
string(2) "31"
["repcontent"]=>
string(41) "Value31"
["count"]=>
string(1) "1"
["date"]=>
string(7) "2007-06"
}
And here an example of my query. I can´t use SUM(CASE) for example beacause index are variable.
SELECT
orders.id,
positions_list.index,
RepK.keynr,
RepK.content AS repcontent,
RepK.p_company,
COUNT(positions_list.index) AS count,
DATE_FORMAT(orders.date_placement, '%Y-%m') AS date
from orders
JOIN tools
ON tools.id=orders.tool_id
JOIN positions_list ON positions_list.order_id = orders.id
LEFT JOIN repkey as RepK
ON RepK.keynr=positions_list.index
AND RepK.p_company=orders.comp_id
WHERE
tools.id =:id
AND RepK.keynr IS NOT NULL
group by DATE_FORMAT(orders.date_placement, '%Y-%m'),positions_list.index

Answer 1

MySQL doesn't currently offer variable width pivots, so you can either:
make two queries, the first to collect the unique repcontent columns, then build a second query to implement a pivot technique by writing a SELECT clause with dynamic CASE WHEN statements for each column or
make one query, and let php prepare the results (this can be scripted up in a few different ways, but I'll recommend this one)
Code: (Demo)
$resultSet = [
['repcontent' => 'Value 27', 'date' => '2019-04'],
['repcontent' => 'Value 28', 'date' => '2019-05'],
['repcontent' => 'Value 28', 'date' => '2019-05'],
['repcontent' => 'Value 32', 'date' => '2019-07'],
['repcontent' => 'Value 32', 'date' => '2019-05'],
];
$columns = array_unique(array_column($resultSet, 'repcontent'));
$lookupKeys = range(1, count($columns));
$lookup = array_combine($columns, $lookupKeys);
$defaults = array_fill_keys($lookupKeys, 0);
foreach ($resultSet as $row) {
if (!isset($result[$row['date']])) {
$result[$row['date']] = array_merge([$row['date']], $defaults);
}
++$result[$row['date']][$lookup[$row['repcontent']]];
}
echo json_encode(array_values($result));
Output:
[["2019-04",1,0,0],["2019-05",0,2,1],["2019-07",0,0,1]]
For simplicity, generate a result set as an array of arrays.
Extract the unique repcontent values
Generate an array with values ranging from 1 to the unique repcontent count
Forge a lookup array consisting of #1 as keys and #2 as values -- this will determine where each "count" will stored when looping later
Create a default array consisting of #2 as keys and zeros as values
Now, loop through the result set and if a given row has a repcontent value which is encountered for the first time, create a new row in the output array using the date as the first element and the elements from #4 to follow.
Unconditionally, add 1 to the row's column that corresponds with with the repcontent value
If you don't quite understand why any of the variables ($columns, $lookupKeys, $lookup, $defaults) are generated or what they contain, call var_export() on my variables before entering the loop -- that should clear up any confusion.
I have a feeling that I could refine your query, but I won't venture a guess without having some realistic sample data to play with.
I don't see why you would need to add additional quotes to your json for the Google chart to work. If the chart doesn't render without the additional quotes, this is probably a symptom that you are passing the php variable to javascript in an improper fashion.
p.s. I see that you some development with Joomla, if this is a Joomla script and you are not able to craft your query with Joomla's query building methods, please post your best effort on Joomla Stack Exchange and I'll see if I can help.