On 2015-04-29 12:20 AM, Olivier Nicole wrote:
>> SELECT * FROM table WHERE item_number=1;
> Sorry if my question was not clear: what I am looking for is:
>
> SELECT * FROM table WHERE data_value=1 AND "there is not any reccord with
> the same item_number and data_value=2"

Assuming a table named t ...

One way, an exclusion join:

select a.*
from t a
left join t b on a.item_number=b.item_number and b.data_value=2
where a.data_value=1 and b.item_number is null;

Another way, with a semi-join:

select a.*
from t a
where a.data_value=1
and not exists (select data_value from t b where
b.item_number=a.item_number and data_value=2);

PB


>
> Olivier
>
>> On Wed, April 29, 2015 06:30, Olivier Nicole wrote:
>>> Hi,
>>>
>>> I am sure that it is feasible with MySQl, and I am sure that's a newbie
>>> question, but my SQL skills are limited...
>>>
>>> I have a table where each record is made of one item_number and one
>>> data_value.
>>>
>>> If one item has several values, there are several records with the same
>>> item_number and a different data_value.
>>>
>>> What is the command to select all the records where an item_number has
>>> the data 1 but not the data 2?
>>>
>>> Thanks in advance,
>>>
>>> Olivier
>> --
>> Mogens Melander
>> +66 8701 33224
>>
>>
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