MySQL select from table depending to other table values

Question

I am sorry for disturbing, but I need little help from you professionals...

I have two tables:

Table1:
ID, date, menu1, menu2, menu3, menu4

and

Table2:
ID, name, somethingElse, somethingElse2

In Table1 (menu1, menu2, menu3, menu4) are IDs of Table2. What I need is query "date" value to database and get four rows from Table2 (depending on menuX values of Table1) Any suggestions, please?

Answer 1

Read the MySQL-docs and look in a MySQL-Tutorial on JOINing. There you will find something like this:

Do a simple SELECT spiced up with a JOIN and tell MySQL to use ID as join-colum:

SELECT Table1.`date` FROM Table1 
JOIN Table2 ON Table1.ID = Table2.ID
WHERE Table1.menu1 = "someValue"
AND Table1.menu2 = "someOtherValue"

If this runs a bit slow try adding an INDEX on one of the tables id-col:

ALTER TABLE Table1 ADD INDEX myIndex (ID)

You can check how many rows are examined by stating

EXPLAIN SELECT Table1.`date` FROM Table1 ...

Answer 2

Ok, now I understand your question. Thanks to your provided examples here is a query that should solve your Problem. The trick here is to use a UNION to append one query result under another. Doing this four times will do the trick:

SELECT b.* FROM dailymenu as a JOIN menu as b ON a.menu1 = b.ID WHERE a.`date` = '2014-10-08'
UNION
SELECT b.* FROM dailymenu as a JOIN menu as b ON a.menu2 = b.ID WHERE a.`date` = '2014-10-08'
UNION
SELECT b.* FROM dailymenu as a JOIN menu as b ON a.menu3 = b.ID WHERE a.`date` = '2014-10-08'
UNION
SELECT b.* FROM dailymenu as a JOIN menu as b ON a.menu4 = b.ID WHERE a.`date` = '2014-10-08'

Your menu sounds very tasty :-)