how to remove "[]" in an json output using php
<p>how can i convert the following json format</p>

<pre><code>[
    [{
        "product_id": 1,
        "name": "Cotton Shirt",
        "sku": "abcdef"
    }],
    [{
        "product_id": 2,
        "name": "Silk Shirt",
        "sku": "csfddef"
    }]
]
</code></pre>

<p>to like below</p>

<pre><code>[{
    "product_id": 1,
    "name": "Cotton Shirt",
    "sku": "abcdef"
}, {
    "product_id": 2,
    "name": "Silk Shirt",
    "sku": "csfddef"
}]
</code></pre>

<p>I just want to remove the extra square bracket.How it is possible</p>