Hi!
>>>>> "Sinisa" == Sinisa Milivojevic <[EMAIL PROTECTED]> writes:
Sinisa> John Heitmann writes:
>> Thanks for the quick response.
>>
>> > > select t1.*, t2.name from t1, t2 where t2.id=t2_id;
>> >
>> > The above is actually expected behaviour, as you are not doing a join
>> > at all, but a full Cartesian product.
>>
>> That t2_id is actually from t1. Sorry for the confusing naming. Here
>> is a more verbose, but identical statement:
>>
>> select t1.*, t2.name from t1, t2 where t2.id=t1.t2_id;
>>
>> Since there is a join condition that works across both tables is this
>> still considered a cartesian product? I did a quick sanity check and
>> the number of rows returned from the problem statement equals the number
>> of rows in t1, rather than t1*t2. Even if it was, I don't see why
>> there is indeterminism in the return values for columns in the result of
>> a cartesian product.
>>
>> Thanks,
>>
>> John
>>
Sinisa> You are right !
Sinisa> This definitely looks like a bug and we shall investigate it further.
The bug was in a combination of doing a join without keys and having
many NULL fields.
Here is now a patch for this (will be in 3.23.49 and MySQL 4.0.2).
===== sql/sql_select.cc 1.116 vs edited =====
*** /tmp/sql_select.cc-1.116-31284 Fri Jan 18 00:43:50 2002
--- edited/sql/sql_select.cc Sun Feb 10 12:32:59 2002
***************
*** 5701,5707 ****
if (null_fields && tables[i].table->null_fields)
{ /* must copy null bits */
copy->str=(char*) tables[i].table->null_flags;
! copy->length=(tables[i].table->null_fields+7)/8;
copy->strip=0;
copy->blob_field=0;
length+=copy->length;
--- 5701,5707 ----
if (null_fields && tables[i].table->null_fields)
{ /* must copy null bits */
copy->str=(char*) tables[i].table->null_flags;
! copy->length=tables[i].table->null_bytes;
copy->strip=0;
copy->blob_field=0;
length+=copy->length;
Regards,
Monty
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