select count(*), target_name_id, ep, avg(bottom), avg(averages)
from
( SELECT avg(bottom) as averages, target_name_id as t,
ep as e
from data_cst
where target_name_id = 44
group by target_name_id, ep, wafer_id) x,
data_cst
where target_name_id = t
and ep = e
group by target_name_id, ep;
Please qualify all fields with table names (or aliases). I can't tell what ep
and e are. Etc.
Please turn the "commajoin" into an explicit JOIN...ON.
> -----Original Message-----
> From: Larry Martell [mailto:larry.mart...@gmail.com]
> Sent: Tuesday, August 21, 2012 3:35 PM
> To: mysql mailing list
> Subject: help with correlated subquery
>
> I am trying to write a query that selects from both a correlated
> subquery and a table in the main query, and I'm having a lot of trouble
> getting the proper row count. I'm sure this is very simple, and I'm
> just missing it. I'll try and present a simple example. For this
> example, there are 27 rows, organized like this:
>
>
> mysql> select count(*), target_name_id, ep, wafer_id from data_cst
> where target_name_id = 44 group by target_name_id, ep, wafer_id;
> +----------+----------------+------+----------+
> | count(*) | target_name_id | ep | wafer_id |
> +----------+----------------+------+----------+
> | 6 | 44 | 1,1 | 16 |
> | 3 | 44 | 1,1 | 17 |
> | 6 | 44 | 1,2 | 16 |
> | 3 | 44 | 1,2 | 17 |
> | 6 | 44 | 1,3 | 16 |
> | 3 | 44 | 1,3 | 17 |
> +----------+----------------+------+----------+
> 6 rows in set (0.00 sec)
>
> I need to get an average of a column grouped by target_name_id, ep as
> well as the average of the averages grouped by target_name_id, ep,
> wafer_id, and I also need the count of the rows in the target_name_id,
> ep group. My query is getting the correct averages, but incorrect row
> counts:
>
> mysql> select count(*), target_name_id, ep, avg(bottom), avg(averages)
> from (select avg(bottom) as averages, target_name_id as t, ep as e from
> data_cst where target_name_id = 44 group by target_name_id, ep,
> wafer_id) x, data_cst where target_name_id = t and ep = e group by
> target_name_id, ep;
> +----------+----------------+------+-------------+-----------------+
> | count(*) | target_name_id | ep | avg(bottom) | avg(averages) |
> +----------+----------------+------+-------------+-----------------+
> | 18 | 44 | 1,1 | 21.8056667 | 21.85458330000 |
> | 18 | 44 | 1,2 | 121.7984444 | 121.83983335000 |
> | 18 | 44 | 1,3 | 349.7634444 | 349.75016665000 |
> +----------+----------------+------+-------------+-----------------+
> 3 rows in set (0.01 sec)
>
> The count for each row should be 9. What do I need in my count() to be
> counting the right thing?
>
>
> TIA!
> -larry
>
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