环境:

    CentOS 7.4 x64
    Nignx 1.14
    PHP 7.2.6
   

配置文件 Nginx.conf 根/root 为 /web/public, phpmyadmin 放在 /web/phpmyadmin，

location /phpmyadmin/ {
    alias /web/phpmyadmin/;
    index index.php index.html index.htm;
    location ~ ^/phpmyadmin/(.+?\.php)(/.*)?$ {
        alias /web/phpmyadmin/;
        fastcgi_split_path_info ^(.+?\.php)(/.*)?$;
        fastcgi_pass 127.0.0.1:9000;
        fastcgi_index index.php;
        fastcgi_param SCRIPT_FILENAME /web/phpmyadmin/$fastcgi_script_name;
        include fastcgi_params;
    }
    location ~ ^/phpmyadmin/(.+)\.(gif|jpg|jpeg|png|bmp|swf|flv|ico)(/.*)?$ {
        alias /web/phpmyadmin/;
        expires 6d;
    }
}

配置代码如上，总是提示 404 错误。
Nignx 错误信息： FastCGI sent in stderr: "Primary script unknown" while reading response header from upstream

使用 root 设置的话就没有问题，无语了。

location /phpmyadmin/ {
    root /web;
    index index.php index.html index.htm;
    location ~ ^/phpmyadmin/(.+?\.php)(/.*)?$ {
        root /web;
        fastcgi_split_path_info ^(.+\.php)(/.+)$;
        fastcgi_pass 127.0.0.1:9000;
        fastcgi_index index.php;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        include fastcgi_params;
    }
    location ~ ^/phpmyadmin/.*\.(gif|jpg|jpeg|png|bmp|swf|flv|ico|js|css)$ {
        root /web;
        expires 7d;
    }
}