個別グループセットに属する最後のxレコードの平均を計算

Question

part_idが見つかった最後の2つのバッチの各part_idの平均時間と、すべてのバッチの各part_idの平均時間を計算しようとしています。

最後に見つけた2つのバッチのpart_idのAverageを分離することができましたが、各パーツIDの計算を行うようにコードに統合することはできません。エラーが発生しました 'where句'の 'tst.part_id'列が不明です。そのtst.part_id値をネストされた選択クエリに渡す必要があります。

以下

私が持っているフィドルです：私が使用しています

http://sqlfiddle.com/#!9/77bea5/85

問合せ：

SELECT tst.part_id, 
    AVG(tst.est_time) AS 'Average Time Overall', 

(SELECT AVG(ft.avgLastMax) 
FROM 
(SELECT t2.avglst as 'avgLastMax', t2.numval as 'numval' 
FROM (SELECT 
     @num:=CASE WHEN @last != tst3.batch_id 
     THEN @num:=(@num + 1) 
     ELSE @num:=@num END 'numval', 
     @last:=tst3.batch_id, 
     @name:=CASE WHEN @num > 2 
     THEN @name:=@name 
     ELSE @name:=(tst3.est_time) END 'avglst' 
     FROM test AS tst3, 
     (select @last:=0, @avg := 0, @name :=0 , @num :=0) var 
     /* GET AVERAGE FOR A SINGLE PART ID 
     WHERE tst3.part_id = 1 */ 
     WHERE tst3.part_id = tst.part_id 
     ORDER BY tst3.run_id DESC) as t2 

) 
as ft 
WHERE ft.numval <3) as 'AVG on last 2 batches' 

FROM test AS tst 
GROUP BY tst.part_id; 

をここでは私が取得しようとしていますものです：

part_id AVG on last 2 batches Average Time Overall 

1   27.25     25.67 

2   22.5      22.5 

3   16.67     16.67 

4   47.5      47.5 

表スキーマ：

CREATE TABLE test 
    (`part_id` int, `est_time` int, `batch_id` int, `run_id` int, `line` varchar(1)) 
; 

INSERT INTO test 
    (`part_id`, `est_time`, `batch_id`, `run_id`, `line`) 
VALUES 
    (1, 20, 1, 1, 'T'), 
    (1, 25, 1, 2, 'T'), 
    (2, 30, 1, 3, 'T'), 
    (3, 15, 1, 4, 'T'), 
    (1, 10, 2, 5, 'X'), 
    (4, 40, 2, 8, 'X'), 
    (2, 15, 3, 9, 'T'), 
    (3, 15, 3, 10, 'T'), 
    (3, 20, 3, 11, 'T'), 
    (1, 34, 4, 12, 'X'), 
    (1, 32, 4, 13, 'X'), 
    (1, 33, 4, 14, 'X'), 
    (4, 55, 5, 15, 'T') 
; 

EDITED：最後のbatch_idを取得するために、DESCによってtst3.run_idによってテーブルと順序が訂正されました。変数と

Answer 1

SELECT W.*,T1.ALLAVG 
FROM (
SELECT V.PART_ID, AVG(V.EST_TIME) LAST2 FROM 
(
SELECT U.PART_ID,U.MAXRN,X.RUN_ID,X.EST_TIME 
FROM 
(
/*LAST 2*/ 
SELECT S.PART_ID,MAX(S.RN) MAXRN 
FROM 
(
/*DERIVE A ROW NUMBER*/ 
SELECT T.PART_ID , T.RUN_ID, 
     IF (CONCAT(T.PART_ID,T.RUN_ID) <> @R ,@RN:=@RN+1,@RN:=1) RN, 
     @R:=CONCAT(T.PART_ID,T.RUN_ID) R 
FROM  (SELECT @RN:=0,@P:=0,@R:=0) RN, TEST T 
ORDER BY T.PART_ID,T.RUN_ID 
) S 
GROUP BY S.PART_ID 
) U 

/*USING THE MAX ABOVE GET THE LAST 2 */ 
JOIN 

(SELECT T.PART_ID , T.RUN_ID,T.EST_TIME, 
     IF (CONCAT(T.PART_ID,T.RUN_ID) <> @R1 ,@RN1:=@RN1+1,@RN1:=1) RN, 
      @R1:=CONCAT(T.PART_ID,T.RUN_ID) R 
FROM  (SELECT @RN1:=0,@P1:=0,@R1:=0) RN, TEST T 
ORDER BY T.PART_ID,T.RUN_ID 

) X ON X.PART_ID = U.PART_ID AND (X.RN BETWEEN U.MAXRN -1 AND U.MAXRN) #AMEND THIS FOR THE LAST N REQUIRED 
) V 
GROUP BY V.PART_ID 
) W 
JOIN 
/*ALL*/ 
(SELECT T.PART_ID,AVG(T.EST_TIME) 'ALLAVG' FROM TEST T GROUP BY T.PART_ID) T1 ON T1.PART_ID = W.PART_ID 

RESULT

+---------+---------+---------+ 
| PART_ID | LAST2 | ALLAVG | 
+---------+---------+---------+ 
|  1 | 32.5000 | 25.6667 | 
|  2 | 22.5000 | 22.5000 | 
|  3 | 17.5000 | 16.6667 | 
|  4 | 47.5000 | 47.5000 | 
+---------+---------+---------+ 

Answer 2

あなたの最初の結果が間違っていると仮定すると...

SELECT a.part_id 
    , AVG(a.est_time) 
    FROM test a 
    JOIN 
    (SELECT x.part_id 
      , x.batch_id 
     FROM 
      (SELECT DISTINCT part_id 
          , batch_id 
         FROM test 
      ) x 
     JOIN 
      (SELECT DISTINCT part_id 
          , batch_id 
         FROM test 
      ) y 
      ON y.part_id = x.part_id 
      AND y.batch_id >= x.batch_id 
     GROUP 
      BY x.part_id 
      , x.batch_id 
     HAVING COUNT(*) <= 2 
    ) b 
    ON b.part_id = a.part_id 
    AND b.batch_id = a.batch_id 
GROUP 
    BY a.part_id; 
+---------+-----------------+ 
| part_id | AVG(a.est_time) | 
+---------+-----------------+ 
|  1 |   27.2500 | 
|  2 |   22.5000 | 
|  3 |   16.6667 | 
|  4 |   47.5000 | 
+---------+-----------------+ 

あるいは、より速く... ...

SELECT part_id 
    , AVG(est_time) last_2_avg 
    FROM 
    (SELECT x.* 
      , CASE WHEN @part_id = part_id 
        THEN CASE WHEN @batch_id = batch_id THEN @i:=@i ELSE @i:=@i+1 END 
        ELSE @i:=1 
        END i 
      , @part_id := part_id 
      , @batch_id:= batch_id 
     FROM test x 
      , (SELECT @part_id := null, @batch_id:=null, @i:=1) vars 
     ORDER 
      BY part_id 
      , batch_id DESC 
    ) a 
WHERE a.i <= 2 
GROUP 
    BY part_id; 

+---------+------------+ 
| part_id | last_2_avg | 
+---------+------------+ 
|  1 | 27.2500 | 
|  2 | 22.5000 | 
|  3 | 16.6667 | 
|  4 | 47.5000 | 
+---------+------------+