SQL连接语句(SQL join statement)

SQL连接语句(SQL join statement)

我有两张桌子需要加在一起，我不确定该怎么做。 我还在努力学习如何加入，我知道有很多不同的类型。 这是我的表格：

laser feature1 feature2 feature laser1 1 1 0 laser2 1 0 1 laser 1 1 0 feature_name feature_text Feature #1 Text 1 Feature #2 Text 2 Feature # Text

如何将这两个表连接在一起，这样我只得到feature_names和feature_texts，其中顶部表中有1？

I have two tables I need to join together and I'm unsure how to do it. I'm still trying to learn how join works and I know there are a bunch of different kinds. Here are my tables:

laser feature1 feature2 feature laser1 1 1 0 laser2 1 0 1 laser 1 1 0 feature_name feature_text Feature #1 Text 1 Feature #2 Text 2 Feature # Text

How do I join these two tables together so I get only the feature_names and feature_texts where there is a 1 in the top table?

最满意答案

这是一个更好的结构：

laser (Table) ------------- laser_name, laser_id feature (Table) --------------- feature_name, feature_texts, feature_id feature_laser (Table) --------------------- laser_id, feature_id

编辑

如果你想看看与feature_id = 1相关的激光器，你可以像这样加入：

select laser_name from laser inner join feature_laser on feature_laser.laser_id = laser.laser_id where feature_id = 1;

如果您想查看与laser_id = 1相关的功能，那么您可以像这样加入：

select feature_name from features inner join feature_laser on feature_laser.feature_id = features.feature_id where laser_id = 1;

Here's a better structure:

laser (Table) ------------- laser_name, laser_id feature (Table) --------------- feature_name, feature_texts, feature_id feature_laser (Table) --------------------- laser_id, feature_id

Edit

If you want to see what lasers are associated with feature_id = 1, then you can join like this:

select laser_name from laser inner join feature_laser on feature_laser.laser_id = laser.laser_id where feature_id = 1;

If you want to see what features are associated with laser_id = 1, then you can join like this:

select feature_name from features inner join feature_laser on feature_laser.feature_id = features.feature_id where laser_id = 1;