Question

我有一个网站供用户查看，让我们说“水果”和“蔬菜”。我有一个fruit_review和一个vegetable_review表。两者都有reviewId，fruitName / vegetableName，reviewText和date字段。

我想在我的索引页面上做一个“最后5条评论”部分。例如。

为此，我使用以下查询：

SELECT reviewId AS id, fruitName AS name, reviewText AS text, date FROM fruit_review
UNION
SELECT reviewId AS id, vegetableName AS name, reviewText AS text, date FROM vegetable_review
ORDER BY date DESC LIMIT 5;

这很有效，但我想将这些结果用作评论的链接。

如何确定我刚收到的评论是属于水果还是蔬菜？（href =“vegetablereview.php？id = $ id”或href =“fruitreview.php？id = $ id“为每个案例？”

我可以在查询中包含一些内容，例如，我可以在php中处理表格的名称吗？

我不想在表中添加任何额外的列（例如，类型列对于水果总是0，对于蔬菜总是1）。

Answer 1

您也可以使用union all。效率更高：

SELECT 'fruit' as which, reviewId AS id, fruitName AS name, reviewText AS text, date FROM fruit_review
UNION ALL
SELECT 'vegetable' as which, reviewId AS id, vegetableName AS name, reviewText AS text, date FROM vegetable_review
ORDER BY date DESC
LIMIT 5;

换句话说，你必须明确地处理它。除非您明确指定，否则MySQL无法识别特定列的表。

Answer 2

您可以添加自定义字段（类型）并使用每行的文本水果或蔬菜填充它。

SELECT reviewId AS id, fruitName AS name, 'fruit' as type, reviewText AS text, date FROM fruit_review
UNION
SELECT reviewId AS id, vegetableName AS name, 'vegetable' as type, reviewText AS text, date FROM vegetable_review
ORDER BY date DESC LIMIT 5;

MySQL在常见查询中分隔两个表

2 个答案: