Trying to "add" one column to a table via SQL JOIN

Question

I want to join two tables together and have ONLY the data in Table 1 (but every record) and add the data from a column in the other table if applicable (there won't be a match for EVERY record)

I tried using a LEFT JOIN matching four columns but I get doubles of some records. If there are 1050 records in table 1 I want 1050 records returned but I get more than that.

Part of the problem is that there aren't any index columns since every column has values that duplicate throughout the column.

Anyway, here is the SQL Statement I tried but I get four extra records (duplicates)

SELECT t1.*, t2.assignedtechnician
FROM idlereport AS t1
LEFT JOIN wipassignedtechnician AS t2
ON (LEFT(t1.rma, 6)=LEFT(t2.rma, 6)
AND t1.receiveddate=t2.receiveddate
AND t1.serial=t2.serial
AND t1.partnumber=t2.partnumber)

P.S. I'm using MySQL

Answer 1

a left join is the right join in this case, i guess your problem is your on part. why do you join on string columns and not on some index?

nevertheless you should never get more rows than in your left table (idlereport)

Answer 2

Problem is that at times there are more than one record in t2 that matches a single record in t1 based on join conditions you specified...

SELECT t1.*, Min(t2.assignedtechnician)
FROM idlereport AS t1
   LEFT JOIN wipassignedtechnician AS t2
       ON (LEFT(t1.rma, 6)=LEFT(t2.rma, 6)
           AND t1.receiveddate=t2.receiveddate
           AND t1.serial=t2.serial 
           AND t1.partnumber=t2.partnumber)
Group By t1.*

or

SELECT t1.*, 
    (Select Min(t2.assignedtechnician)
     From wipassignedtechnician 
     Where LEFT(rma, 6)=LEFT(t1.rma, 6)
           AND receiveddate=t1.receiveddate
           AND serial=t1.serial 
           AND partnumber=t1.partnumber) assignedtechnician
FROM idlereport AS t1