假设我有一张表格看起来像这样：
+----+--------------+-------+----------------+------------+
| id | product_name | price | bulk_reference | bulk_count |
+----+--------------+-------+----------------+------------+
| 1 | xxxx | 11.99 | 0 | 0 |
+----+--------------+-------+----------------+------------+
| 2 | zzzz | 22.99 | 0 | 0 |
+----+--------------+-------+----------------+------------+
| 3 | | | 2 | 10 |
+----+--------------+-------+----------------+------------+
我可以选择所有产品等,没问题.但是 – 我需要做的是返回所有产品,但行WHERE bulk_reference> 0需要返回product_name&的引用行值.行中未设置的价格…在同一结果集中.
例如,我的结果集看起来应该是这样的：
[0] => [id] = 1
[product_name] = xxxx
[price] = 11.99
[bulk_reference] = 0
[bulk_count] = 0
[1] => [id] = 2
[product_name] = zzzz
[price] = 22.99
[bulk_reference] = 0
[bulk_count] = 0
[2] => [id] = 3
[product_name] = zzzz
[price] = 22.99
[bulk_reference] = 2
[bulk_count] = 10
我怎么能只用MySQL做这个？
最佳答案 我认为这样你的情况会很好：
select
P1.id,
IF(bulk_reference>0,(select product_name from Products P2 where P2.id=P1.bulk_reference),P1.product_name) as product_name,
IF(bulk_reference>0,(select price from Products P2 where P2.id=P1.bulk_reference), P1.price) as price,
P1.bulk_reference,
P1.bulk_count
from Products P1;
