Sql, get the average on a group while escaping the where condition

问题

excuse my english but nobody can answer in French ;-)

I'm doing this request :

SELECT AVG(tyd.price) AS avg_price, COUNT(tyd.id_product) AS cnt_id_p, 
       catalog.id_marchand, catalog.id_product, catalog.price AS c_price,
       catalog.img_src, tyd.login AS tyd_l
  FROM catalog 
 INNER JOIN tyd ON catalog.id_marchand = tyd.id_marchand 
               AND catalog.id_product = tyd.id_product
 WHERE tyd.login = "user1@tyd.fr"
   AND tyd.step = "0"
 GROUP BY catalog.id_product, catalog.id_marchand

But of course the AVG & COUNT function doesn't work because my condition where get only one lines.

What i'd like to do is still getting my unique line but get the AVG and COUNT function working. I can do it with two queries but i'd prefer do one.

I hope you'll be able to help me.

Thanks.

P.S : I put an other problem in answer 3. I'm getting mad !

回答1:

Try with

SELECT 
    AVG(tyd.price) AS avg_price, COUNT(tyd.id_product) AS cnt_id_p,
    catalog.id_marchand, catalog.id_product, catalog.price AS c_price, 
    catalog.img_src, tyd.login AS tyd_l
FROM catalog 
INNER JOIN tyd ON catalog.id_marchand = tyd.id_marchand 
              AND catalog.id_product =   tyd.id_product
              AND tyd.step = "0" 
GROUP BY catalog.id_product, catalog.id_marchand
HAVING tyd.login = "user1@tyd.fr"

回答2:

You should include all the columns in the GROUP BY clause that are not part of aggregate function.

SELECT AVG(tyd.price) AS avg_price, COUNT(tyd.id_product) AS cnt_id_p,  
       catalog.id_marchand, catalog.id_product, catalog.price AS c_price, 
       catalog.img_src, tyd.login AS tyd_l 
  FROM catalog  
 INNER JOIN tyd ON catalog.id_marchand = tyd.id_marchand  
               AND catalog.id_product = tyd.id_product 
 WHERE tyd.login = "user1@tyd.fr" 
   AND tyd.step = "0" 
 GROUP BY catalog.id_marchand, catalog.id_product, catalog.price AS c_price, 
       catalog.img_src, tyd.login

回答3:

I'm sorry to ask back but i use the same request with join an other table, like that :

    SELECT AVG(tyd.price) AS avg_price, COUNT(tyd.id_product) AS cnt, tyd.id_marchand, tyd.id_product, catalog.price AS c_price, tyd.price AS t_price, tyd.amount AS t_am, pro_tyd.amount AS p_am, pro_tyd.price AS p_price, catalog.img_src,  tyd.step, tyd.login AS tyd_l
    FROM catalog 
    INNER JOIN tyd
    ON catalog.id_marchand = tyd.id_marchand 
    AND catalog.id_product =   tyd.id_product
    AND tyd.step = "1" 
    INNER JOIN pro_tyd 
    ON tyd.id_marchand = pro_tyd.id_marchand 
    AND tyd.id_product = pro_tyd.id_product
    GROUP BY catalog.id_product, catalog.id_marchand
    HAVING tyd.login = "user1@tyd.fr"

and it only works when tyd.login = "user3@tyd.fr" which is the lower id. doesn't work with user1 or user2...I just can't figure why...!

Here is the table :

id / id_marchand / id_product / login / price / amount / delay / step / time

29 / 1 / 1 / user3@tyd.fr / 344 / 1 / 0 / 1 / 1343297500

120 / 1 / 1 /user2@tyd.fr / 54 / 1 / 0 / 1 / 1343297504

109 / 1 / 1 / user10@tyd.fr / 34 / 1 / 0 / 1 / 1343298598

When HAVING tyd.login = "user3@tyd.fr" it works perfectly. When user1 or user2 i got 0 lines.

来源：https://stackoverflow.com/questions/11740458/sql-get-the-average-on-a-group-while-escaping-the-where-condition

标签

sql