Remove bracket and quotations in JSON_AGG (Aggregate Functions) - sql

Question

public function fetchdrug(Request $search_drug){
$filter_drug = $search_drug->input('search_drug');
$all_drugs = HmsBbrKnowledgebaseDrug::selectRaw('DISTINCT ON (drug_code)
drug_code,
drug_name,
JSON_AGG(drug_dosage) AS dosage_list')
->GroupBy('drug_code', 'drug_name')
->orderBy('drug_code', 'ASC')
->get();
return response()->json([
'all_drugs'=>$all_drugs,
]);
}
I am using JSON_AGG to retrieve multiple lines of drug_dosage and combine them into one, but I am getting a bracket and quotation in my output, how do I take it out?
UPDATE:
I am getting errors in the examples because I am trying solutions using str_replace and preg_replace. my problem is that the target is in an SQL statement so I am suspecting that has something to do with the error since there is other data in the result
Error:
Uncaught TypeError: Cannot use 'in' operator to search for 'length' in
{"drug_code":"CFZU",
"drug_name":"Cefazolin",
"dosage_list":"[\"<=4 mg\/L\", \"<=3 mg\/L\"]"},
{"drug_code":"TZPD","drug_name":"Pip\/Tazobactam",
"dosage_list":"[\"Pip\/Tazobactam\"]"}

Answer 1

You can try string_agg instead JSON_AGG
public function fetchdrug(Request $search_drug){
$filter_drug = $search_drug->input('search_drug');
$all_drugs = HmsBbrKnowledgebaseDrug::selectRaw('DISTINCT ON (drug_code)
drug_code,
drug_name,
string_agg(drug_dosage, ', ') AS dosage_list')
->GroupBy('drug_code', 'drug_name')
->orderBy('drug_code', 'ASC')
->get();
return response()->json([
'all_drugs'=>$all_drugs,
]);
}

Answer 2

Because: JSON_AGG returns JSON ARRAY as STRING. After that you returned json encoded result from controller. This adds unwanted characters for make valid json encoding. (nested quotes must be escaped).
So;
Before sending result, you must json_decode for each record's drug_dosage field.
Example code:
public function fetchdrug(Request $search_drug){
$filter_drug = $search_drug->input('search_drug');
$all_drugs = HmsBbrKnowledgebaseDrug::selectRaw('DISTINCT ON (drug_code)
drug_code,
drug_name,
string_agg(drug_dosage, ', ') AS dosage_list')
->GroupBy('drug_code', 'drug_name')
->orderBy('drug_code', 'ASC')
->get();
foreach($all_drugs as $drug){
//decode postgresql 'json array like string presentation' to array.
$decoded = json_decode($drug->drug_dosage);
// if you want to remove null/empty values use array_filter
$filtered = array_filter($decoded); // default behavior removes falsy values.
// use same field to hold wanted, structured values
$drug->drug_dosage = $filtered;
}
// And return as json response like before.
return response()->json([
'all_drugs'=>$all_drugs,
]);
}