从2个表中选择*，其中CatergoryID为1

Question

我有这些表：

table : _newapp_shop_products_events
+-------+-----------+-----------+-------------------+
|   EventID  |   categoryID    |   Price  |
+-------+-----------+-----------+-------------------+
|   9050    |   1    |   15.00 |
|   5048  |   2    |    12.00  |
+-------+-----------+-----------+-------------------+

table : _newapp_shop_products_categories
+-------+-----------+-----------+-------------------+
|   CategoryID  |   Category_Name    |   photo    |
+-------+-----------+-----------+-------------------+
|   1   |   Tickets    |    one.jpg   |
|   2   |   Voucher    |    two.jpg   |
+-------+-----------+-----------+-------------------+

table : _newapp_shop_products_activitys
+-------+-----------+-----------+-------------------+
|   ActivityID  |   categoryID    |   Price  |
+-------+-----------+-----------+-------------------+
|   80    |   1    |   13.00 |
|   95  |   2    |    18.00  |
+-------+-----------+-----------+-------------------+

这些是通过关系，类别->事件，类别->活动链接的。

我想在一个列表中显示事件和活动（“事件和活动表”而不是_newapp的事件），并且仅显示categoryID = 1的两个表中的项目。我该如何解决？

我试图加入它们或将它们全部选择为一个联合，它返回的行很好，但mysql中的内部链接已损坏。当我单击“活动”的第二个结果集时，id是正确的且价格正确，但是当我单击ID转到相应的ID时，它会生成0行结果，因为它会生成查询：SELECT * FROM representin_nl_-_1.Events WHERE Id = 5但是错误的表格，应改为在SELECT * FROM representin_nl_-_1._newapp_shop_products_activitys WHERE Id = 5中搜索。结果：当我单击它的第一个9050时，它将转到正确的行，但其后的ID为not found。结果：

Answer 1

您可能想要一个UNION

SELECT 'Event' AS Type, EventID AS Id, Price
FROM Events
WHERE CategoryId = 1
UNION ALL
SELECT 'Activity' AS Type, ActivityID AS Id, Price
FROM Activity
WHERE CategoryId = 1

您是什么意思ID冲突？您可以改成这样

SELECT EventID, null AS ActivityId, Price
FROM Events
WHERE CategoryId = 1
UNION ALL
SELECT null, ActivityID, Price
FROM Activity
WHERE CategoryId = 1