How can I join multiple SQL tables using the IDs

Question

I have 4 different tables that I want to join  The tables are structured with columns as follows   TableA - aID   nameA   dID  TableB - bID   nameB   cID   aID  TableC - cID   nameC   date  TableD - dID   nameD   Starting with Table A  I understand how to JOIN tables a and c using b  since b has the Primary Keys for those tables  I want to be able to join table TableD on TableA as well  Below is my SQL statement that first joins tables A and B  then joins that to C   SELECT TableA    TableB    TableC   FROM  TableB INNER JOIN TableA ON TableB aID  TableA aID  INNER JOIN TableC ON TableB cID  Tablec cID  WHERE  DATE TableC date  date now        When I attempt to add another join  to include D  I get an error that  TableD  is unknown    SELECT TableA    TableB    TableC    TableD   FROM  TableB INNER JOIN TableA     ON TableB aID  TableA aID      INNER JOIN TableC ON TableB cID  Tablec cID      INNER JOIN TableA ta ON ta dID  TableD dID      WHERE  DATE TableC date  date now

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

You have not joined TableD  merely selected the TableD FIELD  dID  from one of the tables

[mysql] How can I join multiple SQL tables using the IDs?

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