Question

如果当前表的field等于某个特定值，我想加入另一个表例如:(这不是mysql语法）

SELECT * FROM `products` ( IF products.is_package IS NOT NULL THEN INNER JOIN `packages` )

表产品：

 +----+-----------+
 | id | is_package|
 +----+-----------+
 | 1  |   1       | // which joins package with id 1
 +----+-----------+
 | 2  | NULL      |
 +----+-----------+
 | 3  |   2       | // which joins package with id 2
 +----+-----------+

是否可以在mysql中执行此操作？

Answer 1

 SELECT * FROM `products` LEFT JOIN `packages` 
  ON products.is_package = packages.id

Answer 2

你的if条件你可以把它放在WHERE子句.try this。

  SELECT * FROM `products` LEFT JOIN `packages` 
  ON your_clause_here

使用if语句加入另一个表

2 个答案: