mySQL outer join

Question

I have 2 tables for which I need to run a query on

Table1 has 2 fields: l_id, and name

Table2 also has 2 fields: l_id, and b_id

I need to run a query to get the "name" and "l_id" for all the entries in table1 that do not have an entry in table2 for a given b_id.

Hope this makes some sense

score 10 · Accepted Answer · answered Oct 12 '10 at 20:25

10

select t1.*
from Table1 t1
left outer join Table2 t2 on t1.l_id = t2.l_id
    and t2.b_id = @SomeValue
where t2.l_id is null

answered Oct 12 '10 at 20:25

D'Arcy Rittich

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score 3 · Answer 2 · answered Oct 12 '10 at 20:26

3

You can use an outer join, but I find a sub-query is a little more straightforward. In your case selecting everything from table1 that does not have an id in table2. Reads better...

SELECT * FROM table1 WHERE l_id NOT IN (SELECT l_id FROM table2);

answered Oct 12 '10 at 20:26

Jason McCreary

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this works for me, I just modified that second query to add the b_id condition, but to be fair, RedFilter answered first – Señor Reginold Francis Oct 12 '10 at 20:42
No worries. I missed the b_id part anyway. – Jason McCreary Oct 12 '10 at 22:13

mySQL outer join

2 Answers2