Left Join One Column in Table 1 to Two Columns in Table 2

Question

I have two tables, one is a "phone number" table and the other is a "calls" table. The calls table has two columns of interest: the originating number column (c.orig) and the terminating number column (c.term).

I'm trying to write a MySQL query that will return all records in the call table where NEITHER the c.orig number or the c.term number exist in the numbers table (the "n.num" column in the numbers table).

Here is my SQL query:

    SELECT
        c.id, c.date, c.orig, c.term, c.duration
    FROM calls as c
    LEFT JOIN numbers as n ON (n.num = c.orig AND n.num = c.term)
    WHERE
        c.period = '2012-08' AND
        n.num IS NULL
    GROUP BY c.call_id
    ORDER BY c.call_id
    LIMIT 0,300

Any ideas?

---

Here is some further clarification:

------------------------------
table: numbers
nid     num
1       111-222-3333
2       222-333-4444
3       333-444-5555
------------------------------

------------------------------
table: calls
id      orig            term
1       333-444-5555    999-999-9999
2       999-999-9999    111-222-3333
3       222-333-4444    999-999-9999
4       888-888-8888    999-999-9999
5       777-777-7777    999-999-9999
------------------------------

Call IDs 1, 2, and 3 have at least one of the two numbers (orig or term) that can be found in the numbers table.

Call IDs 4 and 5 are situations where neither of the two phone numbers are not in the numbers table. Those are the records that I'm trying to find. Records where neither phone number is found in the numbers table.

Answer 1

You should Join table twice for this,

 
 
 
  
  SELECT c.id, c.date, c.orig, c.term, c.duration FROM calls as c LEFT JOIN numbers as n ON (n.num = c.orig) LEFT JOIN numbers m ON m.num = c.term WHERE c.period = 'date here' AND m.num IS NULL -- GROUP BY c.call_id ORDER BY c.call_id LIMIT 0,300
 
  

question, i removed your group clause cause i don't see any aggregated function. What else do you want to do?

UPDATE 1

based on your examples above, try this edited one.

Call IDs 4 and 5 are situations where neither of the two phone numbers are not in the numbers table . Those are the records that I'm trying to find. Records where neither phone number is found in the numbers

SELECT  a.*
FROM    calls a
        LEFT JOIN numbers b
            ON a.orig = b.num
        LEFT JOIN numbers c
            ON a.term = c.num
WHERE   b.num IS NULL AND
        c.num IS NULL

SQLFiddle Demo

Hpe this makes sense.

Answer 2

You should keep in mind that, logically, the condition in your ON clause is applied to every single row, not to the lot of them, so you can't really have any single n.num be equal to both c.orig and c.term , unless, of course, the two are the same number (which in your particular case would make no sense).

So, what you actually need to be checking there is whether n.num is equal to either c.orig or c.term . That is, just replace AND with OR and you are done:

SELECT
    c.id, c.date, c.orig, c.term, c.duration
FROM calls as c
LEFT JOIN numbers as n ON (n.num = c.orig  n.num = c.term)
WHERE
    c.period = '2012-08' AND
    n.num IS NULL
GROUP BY c.call_id
ORDER BY c.call_id
LIMIT 0,300

Answer 3

The question already uses the word EXIST. Well, this is axactly why EXISTS exists:

SELECT c.id, c.date, c.orig, c.term, c.duration
FROM calls c
WHERE NOT EXISTS ( SELECT *
   FROM numbers a
   WHERE a.num = c.orig
   )
AND NOT EXISTS ( SELECT *
   FROM numbers b
   WHERE b.num = c.term
   );

The two subqueries could even be combined into one:

SELECT c.id, c.date, c.orig, c.term, c.duration
FROM calls c
WHERE NOT EXISTS ( SELECT *
   FROM numbers ab
   WHERE ab.num = c.orig
   OR ab.num = c.term
   );

NOTE: I omitted the period-condition and the LIMIT, which are both irrelevant to the actual problem.

BTW: "date" is a reserved word in SQL. Better not use it as a column name.