SQL 内连接三表

Inner Join Three Tables

提问by Usman YousafZai

I am working in Oracle APEX.i want to make a report from three tables through INNER JOIN.The Tables are as Fallows.

我在 Oracle APEX 工作。我想从三个表到 .TheINNER JOIN表作为休耕做一个报告。

PATIENT (Par_Id(Pk),Pat_Name,Pat_Gender)

HISTORY (His_Id(Pk),Pat_id(Fk),Treated_By)

患者 (Par_Id(Pk),Pat_Name,Pat_Gender)

历史（His_Id(Pk),Pat_id(Fk),Treated_By）

and

和

Treatment ( Treat_Id, His_id(Fk),Pat_id(Fk) ,Treat_Type ,Charges)

治疗 ( Treat_Id, His_id(Fk), Pat_id(Fk) ,Treat_Type , Charges)

I want to display all the columns in Report mentioned in the above three Tables.

我想显示上面三个表中提到的Report中的所有列。

Thanks.

谢谢。

回答by Rhumborl

You should always specify the columns to return, especially as the tables contain identical column names

您应该始终指定要返回的列，尤其是当表包含相同的列名时

SELECT p.Par_Id, p.Pat_Name, p.Pat_Gender,
    h.His_Id, h.Treated_By,
    t.Treat_Id, t.Treat_Type, t.Charges
FROM Patient p 
INNER JOIN History h 
    ON p.PAR_ID = h.PAT_ID
INNER JOIN Treatment t
    ON h.HIS_ID = t.HIS_ID AND p.PAR_ID = h.PAT_ID

回答by Tikkes

This should do the trick

这应该可以解决问题

SELECT * FROM Patient p 
    INNER JOIN History h 
        ON p.PAR_ID = h.PAT_ID
    INNER JOIN Treatment t
        ON h.HIS_ID = t.HIS_ID AND p.PAR_ID = h.PAT_ID

回答by Muhammad Raheel

It is too simple in mysql

在mysql中太简单了

SELECT 
    * 
FROM PATIENT as p
LEFT JOIN HISTORY as h ON h.Pat_id = p.Pat_Id
LEFT JOIN Treatment as t ON t.His_id = h.His_Id

回答by Pranay Rana

Try this

尝试这个

Select * from 
PATIENT  inner join HISTORY  on par_id=HISTORY.Pat_id
inner join Treatment  on par_id=Treatment.Pat_id