在 SQLite iPhone 中加入查询 [英] Join query in SQLite iPhone

问题描述

我有两个表 Visits 和 Labs
访问具有以下字段:id,patientID
实验室有这些字段:id、VisitID
And Visit.id = Labs.VisitID

I have two tables Visits and Labs
Visit has these fields: id,patientID
Labs has these fields: id, VisitID
And Visit.id = Labs.VisitID

我想获取一位患者的所有旧实验室报告.但是在实验室表中我没有 patientID 字段，因此，我需要使用 visitID 字段，使用它我可以连接到访问表，然后我有 patientID

I want to get all old lab reports of a patient. But in lab table I don't have patientID field, so for that I need to make use of visitID field, using which I can connect to Visit table and there I have patientID

所以现在使用 visitID(一个常见字段)我想找出一个病人的所有旧实验室报告

So now using visitID(a common field) I want to find out all old lab reports of a patient

现在我想得到一个病人的所有实验室(我知道patientID)

Now I want to get all labs of a patient (I know patientID)

有人可以建议我加入查询吗?

Can anyone suggest me join query for this?

推荐答案

这是一个简单的INNER JOIN，对吧?

It's a simple INNER JOIN, right?

SELECT labs.* FROM labs INNER JOIN visit ON visit.id = labs.visitID AND patientID = ?

或者你可以做一个子选择:

Or you can do a subselect:

SELECT labs.* FROM labs WHERE visitID IN (SELECT visit.id FROM visit WHERE patientID = ?)

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