我有一个完全可以工作的mysql查询，它提取所有订单、用户、地址和从woocommerce购买的商品，但是它只单独列出产品，我想为每个显示的产品添加数量。
当前显示“订购的项目”
跑步鞋
步行鞋
显示“订购物品”的位置
3双跑鞋
4双步行鞋

SELECT
  p.ID AS 'Order ID',
  p.post_date AS 'Purchase Date',
  MAX( CASE WHEN pm.meta_key = '_billing_email'       AND p.ID = pm.post_id THEN pm.meta_value END ) AS 'Email Address',
  MAX( CASE WHEN pm.meta_key = '_billing_first_name'  AND p.ID = pm.post_id THEN pm.meta_value END ) AS 'First Name',
  MAX( CASE WHEN pm.meta_key = '_billing_last_name'   AND p.ID = pm.post_id THEN pm.meta_value END ) AS 'Last Name',
  MAX( CASE WHEN pm.meta_key = '_billing_address_1'   AND p.ID = pm.post_id THEN pm.meta_value END ) AS 'Address',
  MAX( CASE WHEN pm.meta_key = '_billing_city'        AND p.ID = pm.post_id THEN pm.meta_value END ) AS 'City',
  MAX( CASE WHEN pm.meta_key = '_billing_state'       AND p.ID = pm.post_id THEN pm.meta_value END ) AS 'State',
  MAX( CASE WHEN pm.meta_key = '_billing_postcode'    AND p.ID = pm.post_id THEN pm.meta_value END ) AS 'Post Code',
    CASE p.post_status
      WHEN 'wc-pending'    THEN 'Pending Payment'
      WHEN 'wc-processing' THEN 'Processing'
      WHEN 'wc-on-hold'    THEN 'On Hold'
      WHEN 'wc-completed'  THEN 'Completed'
      WHEN 'wc-cancelled'  THEN 'Cancelled'
      WHEN 'wc-refunded'   THEN 'Refunded'
      WHEN 'wc-failed'     THEN 'Failed'
    ELSE 'Unknown'
    END AS 'Purchase Status',
  MAX( CASE WHEN pm.meta_key = '_order_total'         AND p.ID = pm.post_id THEN pm.meta_value END ) AS 'Order Total',
  MAX( CASE WHEN pm.meta_key = '_paid_date'           AND p.ID = pm.post_id THEN pm.meta_value END ) AS 'Paid Date',
  ( select group_concat( order_item_name separator '</p>' ) FROM wp_woocommerce_order_items where order_id = p.ID ) AS 'Items Ordered'
FROM  wp_posts AS p
JOIN  wp_postmeta AS pm ON p.ID = pm.post_id
JOIN  wp_woocommerce_order_items AS oi ON p.ID = oi.order_id
WHERE post_type = 'shop_order'
GROUP BY p.ID

我相信woocommerce将数量存储在下表/条目中：

wp_woocommerce_order_itemmeta
  order_item_id
    SELECT wp_woocommerce_order_itemmeta.meta_value
    WHERE wp_woocommerce_order_itemmeta.meta_value = '_qty' and wp_woocommerce_order_itemmeta.order_item_id =

我需要加入到这一部分：

( select group_concat( order_item_name separator '</p>' ) FROM wp_woocommerce_order_items where order_id = p.ID ) AS 'Items Ordered'

提前谢谢。
更新答案：lucek
谢谢lucek，绝对完美。
我已经合并了完整的查询，以防其他人想要复制它。

SELECT
  p.ID AS 'Order ID',
  p.post_date AS 'Purchase Date',
  MAX( CASE WHEN pm.meta_key = '_billing_email'       AND p.ID = pm.post_id THEN pm.meta_value END ) AS 'Email Address',
  MAX( CASE WHEN pm.meta_key = '_billing_first_name'  AND p.ID = pm.post_id THEN pm.meta_value END ) AS 'First Name',
  MAX( CASE WHEN pm.meta_key = '_billing_last_name'   AND p.ID = pm.post_id THEN pm.meta_value END ) AS 'Last Name',
  MAX( CASE WHEN pm.meta_key = '_billing_address_1'   AND p.ID = pm.post_id THEN pm.meta_value END ) AS 'Address',
  MAX( CASE WHEN pm.meta_key = '_billing_city'        AND p.ID = pm.post_id THEN pm.meta_value END ) AS 'City',
  MAX( CASE WHEN pm.meta_key = '_billing_state'       AND p.ID = pm.post_id THEN pm.meta_value END ) AS 'State',
  MAX( CASE WHEN pm.meta_key = '_billing_postcode'    AND p.ID = pm.post_id THEN pm.meta_value END ) AS 'Post Code',
    CASE p.post_status
      WHEN 'wc-pending'    THEN 'Pending Payment'
      WHEN 'wc-processing' THEN 'Processing'
      WHEN 'wc-on-hold'    THEN 'On Hold'
      WHEN 'wc-completed'  THEN 'Completed'
      WHEN 'wc-cancelled'  THEN 'Cancelled'
      WHEN 'wc-refunded'   THEN 'Refunded'
      WHEN 'wc-failed'     THEN 'Failed'
    ELSE 'Unknown'
    END AS 'Purchase Status',
  MAX( CASE WHEN pm.meta_key = '_order_total'         AND p.ID = pm.post_id THEN pm.meta_value END ) AS 'Order Total',
  MAX( CASE WHEN pm.meta_key = '_paid_date'           AND p.ID = pm.post_id THEN pm.meta_value END ) AS 'Paid Date',
  ( SELECT GROUP_CONCAT(CONCAT(m.meta_value, ' x ', i.order_item_name) separator '</br>' )
    FROM wp_woocommerce_order_items i
    JOIN wp_woocommerce_order_itemmeta m ON i.order_item_id = m.order_item_id AND meta_key = '_qty'
    WHERE i.order_id = p.ID AND i.order_item_type = 'line_item') AS 'Items Ordered',
  MAX( CASE WHEN pm.meta_key = 'post_excerpt'         AND p.ID = pm.post_id THEN pm.meta_value END ) AS 'User Comments'
FROM  wp_posts AS p
JOIN  wp_postmeta AS pm ON p.ID = pm.post_id
JOIN  wp_woocommerce_order_items AS oi ON p.ID = oi.order_id
WHERE post_type = 'shop_order'
GROUP BY p.ID