Re: help with correlated subquery
On Tue, Aug 21, 2012 at 8:26 PM, Larry Martell larry.mart...@gmail.com wrote: On Tue, Aug 21, 2012 at 8:07 PM, h...@tbbs.net wrote: 2012/08/21 16:35 -0600, Larry Martell 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 | 21.8545833 | | 18 | 44 | 1,2 | 121.798 | 121.83983335000 | | 18 | 44 | 1,3 | 349.763 | 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? Your trouble lys in the joining; in effect, you are joining a row with wafer_id 16 with a row with wafer_id 17, and also a row with wafer_id 17 with a row with wafer_id 16. A further advantage to using the now standard form of joining, as Rick James bids you do, is that one can add further conditions to it: select count(*), target_name_id, ep, avg(bottom), avg(averages) from (select avg(bottom) as averages, target_name_id, ep from data_cst where target_name_id = 44 group by target_name_id, ep, wafer_id) x JOIN data_cst ON target_name_id = x.target_name_id and ep = x.ep and wafer_id x.wafer_id group by target_name_id, ep The inequality, maybe, will give you what you want. Not, wafer_id x.wafer_id, but wafer_id = x.wafer_id - adding that makes it work the way I want. Thanks!! So now that I have this working, that have added another requirement. They also want a count of rows aggregated by a different set of columns. So I need to add another subquery, but I can't figure out how to get the row count. In this example query: mysql select count(*) from data_cst where target_name_id=208082 and wafer_id=425845 group by target_name_id,wafer_id,lot_id,data_file_id; +--+ | count(*) | +--+ | 12 | | 12 | | 12 | | 12 | +--+ 4 rows in set (0.00 sec) The result I need is 4 (i.e there were 4 distinct groups of target_name_id,wafer_id,lot_id,data_file_id). How can I get that? This will be a subquery, so I can't use mysql_num_rows() or FOUND_ROWS() after the fact. I need the result returned from the query. -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql
Re: help with correlated subquery
On Thu, Aug 23, 2012 at 8:08 AM, Larry Martell larry.mart...@gmail.com wrote: On Tue, Aug 21, 2012 at 8:26 PM, Larry Martell larry.mart...@gmail.com wrote: On Tue, Aug 21, 2012 at 8:07 PM, h...@tbbs.net wrote: 2012/08/21 16:35 -0600, Larry Martell 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 | 21.8545833 | | 18 | 44 | 1,2 | 121.798 | 121.83983335000 | | 18 | 44 | 1,3 | 349.763 | 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? Your trouble lys in the joining; in effect, you are joining a row with wafer_id 16 with a row with wafer_id 17, and also a row with wafer_id 17 with a row with wafer_id 16. A further advantage to using the now standard form of joining, as Rick James bids you do, is that one can add further conditions to it: select count(*), target_name_id, ep, avg(bottom), avg(averages) from (select avg(bottom) as averages, target_name_id, ep from data_cst where target_name_id = 44 group by target_name_id, ep, wafer_id) x JOIN data_cst ON target_name_id = x.target_name_id and ep = x.ep and wafer_id x.wafer_id group by target_name_id, ep The inequality, maybe, will give you what you want. Not, wafer_id x.wafer_id, but wafer_id = x.wafer_id - adding that makes it work the way I want. Thanks!! So now that I have this working, that have added another requirement. They also want a count of rows aggregated by a different set of columns. So I need to add another subquery, but I can't figure out how to get the row count. In this example query: mysql select count(*) from data_cst where target_name_id=208082 and wafer_id=425845 group by target_name_id,wafer_id,lot_id,data_file_id; +--+ | count(*) | +--+ | 12 | | 12 | | 12 | | 12 | +--+ 4 rows in set (0.00 sec) The result I need is 4 (i.e there were 4 distinct groups of target_name_id,wafer_id,lot_id,data_file_id). How can I get that? This will be a subquery, so I can't use mysql_num_rows() or FOUND_ROWS() after the fact. I need the result returned from the query. I got this working: select count(distinct lot_id,data_file_id) from data_cst where target_name_id=208082 and wafer_id=425845; -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql
RE: help with correlated subquery
assign realistic alias names OuterJoin should be called OuterJoin InnerJoin should be called InnerJoin If you want only the most restricitive criteria that match resultsets from both select statements use INNER JOIN if you want all results from both resultsets (cartesian JOIN) use OUTER JOIN Finally: Be aware FUNCTIONS such as AVG cast off indexing and should be avoided unless the FUNCTION(columnName) itself is indexed GROUP BY re-arranges your query so its best to introduce GROUP BY in stages use realistic alias names like Dept and EmployeeNumber and avoid aliases that cause confusion like 'a' or 'foo' Develop in stages and write down what YOU EXPECT vs WHAT each query produces .. If the Individual Select doesnt produce expected results..STOP and correct the SELECT Statement Diagram out what you expect results from any of the INNER JOIN, OUTER JOIN, LEFT JOIN or RIGHT JOIN operations will produce If the executed JOIN Statement does not produce expected results STOP and correct the JOIN clause BEFORE incorporating more functionality Obfuscation and confusion can hopelessly sidetrack any intelligent analysis Martin __ Verzicht und Vertraulichkeitanmerkung/Note de déni et de confidentialité Diese Nachricht ist vertraulich. Sollten Sie nicht der vorgesehene Empfaenger sein, so bitten wir hoeflich um eine Mitteilung. Jede unbefugte Weiterleitung oder Fertigung einer Kopie ist unzulaessig. Diese Nachricht dient lediglich dem Austausch von Informationen und entfaltet keine rechtliche Bindungswirkung. Aufgrund der leichten Manipulierbarkeit von E-Mails koennen wir keine Haftung fuer den Inhalt uebernehmen. Ce message est confidentiel et peut être privilégié. Si vous n'êtes pas le destinataire prévu, nous te demandons avec bonté que pour satisfaire informez l'expéditeur. N'importe quelle diffusion non autorisée ou la copie de ceci est interdite. Ce message sert à l'information seulement et n'aura pas n'importe quel effet légalement obligatoire. Étant donné que les email peuvent facilement être sujets à la manipulation, nous ne pouvons accepter aucune responsabilité pour le contenu fourni. Date: Tue, 21 Aug 2012 20:26:51 -0600 Subject: Re: help with correlated subquery From: larry.mart...@gmail.com To: h...@tbbs.net CC: mysql@lists.mysql.com On Tue, Aug 21, 2012 at 8:07 PM, h...@tbbs.net wrote: 2012/08/21 16:35 -0600, Larry Martell 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 | 21.8545833 | | 18 | 44 | 1,2 | 121.798 | 121.83983335000 | | 18 | 44 | 1,3 | 349.763 | 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? Your trouble lys in the joining; in effect, you are joining a row with wafer_id 16 with a row with wafer_id 17, and also a row with wafer_id 17 with a row with wafer_id 16. A further advantage to using the now standard form of joining, as Rick James bids you do, is that one can add further conditions
RE: help with correlated subquery
The inner query has multiple rows because of wafer_id. The outer query then gives you multiple copies, hence screwing up the COUNT. Also, the AVG(AVG()) is mathematically incorrect unless the counts are identical. -Original Message- From: Larry Martell [mailto:larry.mart...@gmail.com] Sent: Tuesday, August 21, 2012 7:27 PM To: h...@tbbs.net Cc: mysql@lists.mysql.com Subject: Re: help with correlated subquery On Tue, Aug 21, 2012 at 8:07 PM, h...@tbbs.net wrote: 2012/08/21 16:35 -0600, Larry Martell 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 | 21.8545833 | | 18 | 44 | 1,2 | 121.798 | 121.83983335000 | | 18 | 44 | 1,3 | 349.763 | 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? Your trouble lys in the joining; in effect, you are joining a row with wafer_id 16 with a row with wafer_id 17, and also a row with wafer_id 17 with a row with wafer_id 16. A further advantage to using the now standard form of joining, as Rick James bids you do, is that one can add further conditions to it: select count(*), target_name_id, ep, avg(bottom), avg(averages) from (select avg(bottom) as averages, target_name_id, ep from data_cst where target_name_id = 44 group by target_name_id, ep, wafer_id) x JOIN data_cst ON target_name_id = x.target_name_id and ep = x.ep and wafer_id x.wafer_id group by target_name_id, ep The inequality, maybe, will give you what you want. Not, wafer_id x.wafer_id, but wafer_id = x.wafer_id - adding that makes it work the way I want. Thanks!! -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql
Re: help with correlated subquery
Hello Martin, On 8/22/2012 8:30 AM, Martin Gainty wrote: assign realistic alias names OuterJoin should be called OuterJoin InnerJoin should be called InnerJoin Almost! MySQL does not have a simple OUTER JOIN command (some RDBMSes call this a FULL OUTER JOIN). What we do have is the option to include the OUTER keyword into our LEFT or RIGHT joins. For example, both of these are acceptable: LEFT OUTER JOIN LEFT JOIN Also, you need a space between inner and join as in INNER JOIN. If you want only the most restricitive criteria that match resultsets from both select statements use INNER JOIN if you want all results from both resultsets (cartesian JOIN) use OUTER JOIN Again, MySQL does not have a plain OUTER JOIN. If you want a full Cartesian product of two tables, use the 'comma join' syntax with no criteria for matching the tables in the WHERE clause. SELECT ... FROM tableA, tableB WHERE Syntax details are located here: http://dev.mysql.com/doc/refman/5.5/en/join.html Finally: Be aware FUNCTIONS such as AVG cast off indexing and should be avoided unless the FUNCTION(columnName) itself is indexed GROUP BY re-arranges your query so its best to introduce GROUP BY in stages Not exactly. If you wrap a column in a function and attempt to use the results of that function in the WHERE clause, then you are correct. However based on the way your define your indexes, the data you process in a function may actually come from the index and save you a trip to the underlying table. In this case, the index could make your function faster by skipping an additional retrieval step. use realistic alias names like Dept and EmployeeNumber and avoid aliases that cause confusion like 'a' or 'foo' Excellent advice. Develop in stages and write down what YOU EXPECT vs WHAT each query produces .. If the Individual Select doesnt produce expected results..STOP and correct the SELECT Statement Also excellent advice. Diagram out what you expect results from any of the INNER JOIN, OUTER JOIN, LEFT JOIN or RIGHT JOIN operations will produce If the executed JOIN Statement does not produce expected results STOP and correct the JOIN clause BEFORE incorporating more functionality Obfuscation and confusion can hopelessly sidetrack any intelligent analysis Well put! -- Shawn Green MySQL Principal Technical Support Engineer Oracle USA, Inc. - Hardware and Software, Engineered to Work Together. Office: Blountville, TN -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql
RE: help with correlated subquery
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 | 21.8545833 | | 18 | 44 | 1,2 | 121.798 | 121.83983335000 | | 18 | 44 | 1,3 | 349.763 | 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 -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql
Re: help with correlated subquery
On Tue, Aug 21, 2012 at 5:30 PM, Rick James rja...@yahoo-inc.com wrote: 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. select count(*), target_name_id as target, ep as 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 join (data_cst) on data_cst.target_name_id = x.t and ep = x.e group by target_name_id, ep; Returns the same result set. -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 | 21.8545833 | | 18 | 44 | 1,2 | 121.798 | 121.83983335000 | | 18 | 44 | 1,3 | 349.763 | 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 -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql
Re: help with correlated subquery
On Tue, Aug 21, 2012 at 5:39 PM, Martin Gainty mgai...@hotmail.com wrote: a look at the first query: 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 | a look at the second query which references the 1st query 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 nt er_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 | 21.8545833 | | 18 | 44 | 1,2 | 121.798 | 121.83983335000 | | 18 | 44 | 1,3 | 349.763 | 349.75016665000 | you have 3 rows returned based on wafer_id wafer_id = 16 returns count of 6 count of 6 count of 6 count(*) = 18 but you dont want the rows aggregated by wafer_id (or any other criteria) you want your rows aggregated by only column ep (1,1 with 1,1) ROW 1 and ROW 2 c (1,2 with 1,2) ROW3 and ROW 4 (1,3 with 1,3) ROW5 and ROW6 so i would group ONLY on ep No, I need to aggregate on target_name_id and ep. In the real app there are multiple target_name_ids being selected. I was trying to present a simple example. Its a tough call without seeing each query executed individually what I do is build out the query column at a time and then I add in group by then I add in aggregate functions avg(bottom) avg(averages) that way I can see each variable being used and which one delivers correct result (and which variable goes fubar) I've done that. The inner query gives the expected results: mysql select target_name_id as t, ep as e, avg(bottom) as averages from data_cst where target_name_id = 44 group by target_name_id, ep, wafer_id; ++--+-+ | t | e| averages| ++--+-+ | 44 | 1,1 | 21.7078333 | | 44 | 1,1 | 22.001 | | 44 | 1,2 | 121.7156667 | | 44 | 1,2 | 121.964 | | 44 | 1,3 | 349.790 | | 44 | 1,3 | 349.710 | ++--+-+ 6 rows in set (0.00 sec) As does the outer one: mysql select count(*), target_name_id as target, ep as ep, avg(bottom) from data_cst where target_name_id = 44 group by target_name_id, ep; +--++--+-+ | count(*) | target | ep | avg(bottom) | +--++--+-+ |9 | 44 | 1,1 | 21.8056667 | |9 | 44 | 1,2 | 121.798 | |9 | 44 | 1,3 | 349.763 | +--++--+-+ 3 rows in set (0.00 sec) It only when I combine them that I am double counting the target, ep rows. I think I see why (there are 2 wafers for each target, ep), but I don't know how to avoid that. I need to group by target_name_id, ep, wafer_id in the inner query, and then I need to group by target_name_id, ep in the outer one. I only want to count the number of target_name_id, ep groups. Date: Tue, 21 Aug 2012 16:35:23 -0600 Subject: help with correlated subquery From: larry.mart...@gmail.com To: mysql@lists.mysql.com 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
Re: help with correlated subquery
2012/08/21 16:35 -0600, Larry Martell 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 | 21.8545833 | | 18 | 44 | 1,2 | 121.798 | 121.83983335000 | | 18 | 44 | 1,3 | 349.763 | 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? Your trouble lys in the joining; in effect, you are joining a row with wafer_id 16 with a row with wafer_id 17, and also a row with wafer_id 17 with a row with wafer_id 16. A further advantage to using the now standard form of joining, as Rick James bids you do, is that one can add further conditions to it: select count(*), target_name_id, ep, avg(bottom), avg(averages) from (select avg(bottom) as averages, target_name_id, ep from data_cst where target_name_id = 44 group by target_name_id, ep, wafer_id) x JOIN data_cst ON target_name_id = x.target_name_id and ep = x.ep and wafer_id x.wafer_id group by target_name_id, ep The inequality, maybe, will give you what you want. -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql
Re: help with correlated subquery
On Tue, Aug 21, 2012 at 8:07 PM, h...@tbbs.net wrote: 2012/08/21 16:35 -0600, Larry Martell 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 | 21.8545833 | | 18 | 44 | 1,2 | 121.798 | 121.83983335000 | | 18 | 44 | 1,3 | 349.763 | 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? Your trouble lys in the joining; in effect, you are joining a row with wafer_id 16 with a row with wafer_id 17, and also a row with wafer_id 17 with a row with wafer_id 16. A further advantage to using the now standard form of joining, as Rick James bids you do, is that one can add further conditions to it: select count(*), target_name_id, ep, avg(bottom), avg(averages) from (select avg(bottom) as averages, target_name_id, ep from data_cst where target_name_id = 44 group by target_name_id, ep, wafer_id) x JOIN data_cst ON target_name_id = x.target_name_id and ep = x.ep and wafer_id x.wafer_id group by target_name_id, ep The inequality, maybe, will give you what you want. Not, wafer_id x.wafer_id, but wafer_id = x.wafer_id - adding that makes it work the way I want. Thanks!! -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql