Laravel中使用DB::raw统计含null值的provider数据并生成图表问题

Got it, let's get those NULL provider values showing up in your stats! The issue here is that while some databases do group NULLs as a distinct group, they might not be captured cleanly in your query, or the resulting "null" label in your chart isn't very user-friendly. Here's how to adjust your code to count those records properly:

Modified Query #

$providercounter = DB::table('users')
    ->select(
        DB::raw('count(*) as count'),
        // Replace NULL values with a readable label (e.g., "No Provider")
        DB::raw('COALESCE(provider, "No Provider") as provider')
    )
    // Group by the same COALESCE expression to include NULLs
    ->groupBy(DB::raw('COALESCE(provider, "No Provider")'))
    ->orderBy('count','desc')
    ->get();

What's Changed? #

• COALESCE(provider, "No Provider"): This SQL function checks if the provider value is NULL. If it is, it replaces it with the string "No Provider" (you can change this to any label you prefer, like "Unspecified"). This ensures NULLs are treated as a valid, named group instead of being overlooked.
• Group by the same expression: We group by the modified provider value (the COALESCE result) to make sure all NULL records are grouped together under our custom label.

The Rest of Your Code Stays the Same #

Your existing loop and chart setup will work perfectly with this adjusted query:

foreach($providercounter as $provider){ 
    $name[] = $provider->provider; 
    $count[] = $provider->count; 
}

$providerUsers = Charts::create('bar', 'highcharts')
    ->title('Providers users')
    ->labels($name)
    ->values($count)
    ->responsive(true);

Now your bar chart will include a bar for all users with no provider set, labeled clearly as "No Provider" (or whatever you chose in the COALESCE function).

Note for Different Databases #

If you're using PostgreSQL instead of MySQL, just swap the double quotes around the label to single quotes:

COALESCE(provider, 'No Provider')

内容的提问来源于stack exchange，提问作者mafortis