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How can I join multiple SQL tables using the IDs?

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sql

join

mysql

People also ask

How do I combine multiple tables into one in SQL?

The simplest way to combine two tables together is using the keywords UNION or UNION ALL. These two methods pile one lot of selected data on top of the other. The difference between the two keywords is that UNION only takes distinct values, but UNION ALL keeps all of the values selected.

Can we join more than 3 tables in SQL?

It is possible to use multiple join statements together to join more than one table at the same time. To do that you add a second INNER JOIN statement and a second ON statement to indicate the third table and the second relationship.


You want something more like this:

SELECT TableA.*, TableB.*, TableC.*, TableD.*
FROM TableA
    JOIN TableB
        ON TableB.aID = TableA.aID
    JOIN TableC
        ON TableC.cID = TableB.cID
    JOIN TableD
        ON TableD.dID = TableA.dID
WHERE DATE(TableC.date)=date(now()) 

In your example, you are not actually including TableD. All you have to do is perform another join just like you have done before.

A note: you will notice that I removed many of your parentheses, as they really are not necessary in most of the cases you had them, and only add confusion when trying to read the code. Proper nesting is the best way to make your code readable and separated out.


SELECT 
    a.nameA, /* TableA.nameA */
    d.nameD /* TableD.nameD */
FROM TableA a 
    INNER JOIN TableB b on b.aID = a.aID 
    INNER JOIN TableC c on c.cID = b.cID 
    INNER JOIN TableD d on d.dID = a.dID 
WHERE DATE(c.`date`) = CURDATE()

You have not joined TableD, merely selected the TableD FIELD (dID) from one of the tables.


Simple INNER JOIN VIEW code....

CREATE VIEW room_view
AS SELECT a.*,b.*
FROM j4_booking a INNER JOIN j4_scheduling b
on a.room_id = b.room_id;