如何将子数组数据归并至对应父数组？PHP实现需求

Here's a cleaned-up version of your code that will produce the exact structure you're looking for. I've fixed redundant queries, corrected structural issues, and aligned the output with your desired JSON format:

<?php
// Fetch all parent categories in a single query (no need to re-fetch inside the loop)
$parents = $this->db->get('dynamic_parent_category')->result_array();

// Iterate over each parent to attach its corresponding subcategories
foreach ($parents as &$parent) {
    // Use CodeIgniter's query builder to get subcategories linked to this parent
    $subcategories = $this->db
        ->where('parent_cat_id', $parent['df_cat_id'])
        ->get('dynamic_sub_category')
        ->result_array();
    
    // Add the subcategories as a 'childData' property directly to the parent object
    $parent['childData'] = $subcategories;
}

// Construct the final response matching your desired output structure
$finalResponse = [
    'status' => 200,
    'message' => 'Success',
    'child' => [
        'Parent' => $parents
    ]
];

return $finalResponse;
?>

Key improvements made: #

1. Eliminated redundant queries: Your original code was re-fetching the same parent category inside the loop (which also used the wrong query variable $query instead of $parentQuery). We now fetch all parents once upfront.
2. Structured output correctly: Instead of creating a separate array with the typo parnet and child keys, we directly add the childData array to each parent object to match your desired JSON structure.
3. Safer querying: Used CodeIgniter's query builder methods (where(), get()) instead of concatenating SQL strings, which helps prevent SQL injection vulnerabilities.
4. Cleaner code flow: The logic is straightforward - get parents, attach their subcategories, wrap in the required response structure.

This code will return exactly the JSON output you provided in your "期望输出结构" section.

内容的提问来源于stack exchange，提问作者Gaurav Jariwala