如何在MySQL中使用子查詢為報表優化多個聯接的查詢

Question

我在應用程序中定義了以下表格，以根據培訓日期獲取每個地區的報告。

wi_individual_g(ind_id, ind_district_id, ...)
wi_individual_p(ind_id,prg_id, ind_dalit (yes/no), ind_madhesi (yes/no), ...)
wi_training(trn_id, trn_start_date, trn_ben_type, ...)
wi_indv_training(trn_id, ind_id)
wi_district(dst_id,dst_name)

我的問題：必須生成報告以對與給定trn_start_date之間的培訓相關聯的地區個人進行計數。 該應用程序具有預定義的日期范圍，其季度如下所示：

$quarter=array('y1q3'=>array('2013-02-01','2013-03-31'),'y1q4'=>array('2013-04-01','2013-06-30')
,'y2q1'=>array('2013-07-01','2013-09-30'),'y2q2'=>array('2013-10-01','2013-012-31'),'y2q3'=>array('2014-01-01','2014-03-31'),'y2q4'=>array('2014-04-01','2014-06-30')
,'y3q1'=>array('2014-07-01','2014-09-30'),'y3q2'=>array('2014-10-01','2014-012-31'),'y3q3'=>array('2015-01-01','2015-03-31'),'y3q4'=>array('2015-04-01','2015-06-30')
,'y4q1'=>array('2015-07-01','2015-09-30'),'y4q2'=>array('2015-10-01','2015-012-31'),'y4q3'=>array('2016-01-01','2016-03-31'),'y4q4'=>array('2016-04-01','2016-06-30')
,'y5q1'=>array('2016-07-01','2016-09-30'),'y5q2'=>array('2016-10-01','2016-012-31'),'y5q3'=>array('2017-01-01','2017-03-31'),'y5q4'=>array('2017-04-01','2017-06-30')
,'y6q1'=>array('2017-07-01','2017-09-30'),'y6q2'=>array('2017-10-01','2017-012-31'),'y6q3'=>array('2018-01-01','2018-03-31'),'y6q4'=>array('2018-04-01','2018-06-30')); 

如果將trn_start_date選擇為Y4Q4，則查詢必須針對每個日期范圍按區域對個人進行計數，例如：Y1（Q1-Q4），Y2（Q2-Q4），Y3（Q1-Q4），Y4（Q1-Q4）與單個查詢分別為：

Y1  Y2    Y3    Y4  Y5  Y6
8   3948  3511  0   0   0

作為解決方案，我應用了以下查詢：

SELECT wi_district.dst_name, 
COUNT(DISTINCT(CASE WHEN wi_training.trn_start_date BETWEEN '2017-07-01' AND '2018-06-30' AND 
ind_dalit='yes' THEN wi_individual_g.ind_id END)) AS y6 , 
COUNT(DISTINCT(CASE WHEN wi_training.trn_start_date BETWEEN '2016-07-01' AND '2017-06-30' AND     ind_dalit='yes' THEN wi_individual_g.ind_id END)) AS y5 , 
COUNT(DISTINCT(CASE WHEN wi_training.trn_start_date BETWEEN '2015-07-01' AND '2016-06-30' AND ind_dalit='yes' THEN wi_individual_g.ind_id END)) AS y4 , 
COUNT(DISTINCT(CASE WHEN wi_training.trn_start_date BETWEEN '2014-07-01' AND '2015-06-30' AND ind_dalit='yes' THEN wi_individual_g.ind_id END)) AS y3 , 
COUNT(DISTINCT(CASE WHEN wi_training.trn_start_date BETWEEN '2013-07-01' AND '2014-06-30' AND ind_dalit='yes' THEN wi_individual_g.ind_id END)) AS y2 , 
COUNT(DISTINCT(CASE WHEN wi_training.trn_start_date BETWEEN '2013-02-01' AND '2013-06-30' AND ind_dalit='yes' THEN wi_individual_g.ind_id END)) AS y1 
FROM wi_individual_g 
INNER JOIN wi_individual_p ON wi_individual_p.ind_id=wi_individual_g.ind_id AND wi_individual_g.ind_is_recepient='yes' 
INNER JOIN wi_district ON wi_district.dst_id=wi_individual_g.ind_district_id AND wi_individual_g.ind_deleted=0 
INNER JOIN wi_indv_training ON wi_indv_training.ind_id=wi_individual_g.ind_id AND wi_indv_training.is_deleted=0 
INNER JOIN wi_training ON wi_training.trn_id=wi_indv_training.trn_id AND wi_training.trn_deleted=0 AND wi_training.trn_beneficiary_type=2 AND wi_training.trn_start_date <='2018-06-30' 
GROUP BY wi_district.dst_name

但是此查詢需要5分鍾以上的時間才能執行，這是最糟糕的情況。 我也將索引應用於字段，但取得了一些相同的結果。 如果有人為我提供最佳解決方案，我將不勝感激。

Answer 1

我對查詢做了些微改動，以將條件調整為相應的聯接，或在適用的情況下放入WHERE子句。 我還將“ ind_dalit = yes”組件移到wi_individual_p表的JOIN中，而在每種情況下都是這樣。

這樣，我可以更好地看到提供索引建議的條件，包括

table              index
wi_individual_g    ( ind_is_recipient, ind_deleted, ind_id, ind_district_id )
wi_individual_p    ( ind_id, ind_dalit )
wi_district        ( dst_id, dst_name )
wi_indv_training   ( ind_id, is_deleted )
wi_training        ( trn_beneficiary_type, trn_deleted, trn_start_date, trn_id )

SELECT 
      d.dst_name, 
      COUNT( DISTINCT( CASE WHEN t.trn_start_date 
         BETWEEN '2017-07-01' AND '2018-06-30' 
         THEN g.ind_id END)) AS y6,
      COUNT( DISTINCT( CASE WHEN t.trn_start_date 
         BETWEEN '2016-07-01' AND '2017-06-30' 
         THEN g.ind_id END)) AS y5,
      COUNT( DISTINCT( CASE WHEN t.trn_start_date 
         BETWEEN '2015-07-01' AND '2016-06-30' 
         THEN g.ind_id END)) AS y4, 
      COUNT( DISTINCT( CASE WHEN t.trn_start_date 
         BETWEEN '2014-07-01' AND '2015-06-30' 
         THEN g.ind_id END)) AS y3, 
      COUNT( DISTINCT( CASE WHEN t.trn_start_date 
         BETWEEN '2013-07-01' AND '2014-06-30' 
         THEN g.ind_id END)) AS y2, 
      COUNT( DISTINCT( CASE WHEN t.trn_start_date 
         BETWEEN '2013-02-01' AND '2013-06-30' 
         THEN g.ind_id END)) AS y1 
   FROM 
      wi_individual_g g
         INNER JOIN wi_individual_p p
            ON g.ind_id = p.ind_id
            AND p.ind_dalit='yes' 
         INNER JOIN wi_district d
            ON g.ind_district_id = d.dst_id 
         INNER JOIN wi_indv_training wit 
            ON g.ind_id = wit.ind_id
            AND wit.is_deleted = 0 
         INNER JOIN wi_training t
            ON wit.trn_id = t.trn_id 
            AND t.trn_beneficiary_type = 2 
            AND t.trn_deleted = 0 
            AND t.trn_start_date >= '2013-02-01'
            AND t.trn_start_date <= '2018-06-30' 
   WHERE
          g.ind_is_recepient = 'yes' 
      AND g.ind_deleted = 0
   GROUP BY 
      d.dst_name

這是您可以嘗試的另一種選擇。 此預查詢（別名PQ）每個日期組1-6的“ g”區和ind_id與返回每個帶日期的記錄不同。 這樣，結果便是每個區的簡單總和。

SELECT 
      d.dst_name, 
      SUM( PQ.DateGrp = 6 ) AS y6,
      SUM( PQ.DateGrp = 5 ) AS y5,
      SUM( PQ.DateGrp = 4 ) AS y4,
      SUM( PQ.DateGrp = 3 ) AS y3,
      SUM( PQ.DateGrp = 2 ) AS y2,
      SUM( PQ.DateGrp = 1 ) AS y1
   FROM 
      ( select distinct 
              g.ind_district_id, 
              g.ind_id,
              CASE WHEN t.trn_start_date BETWEEN '2017-07-01' AND '2018-06-30' THEN 6 
                   WHEN t.trn_start_date BETWEEN '2016-07-01' AND '2017-06-30' THEN 5
                   WHEN t.trn_start_date BETWEEN '2015-07-01' AND '2016-06-30' THEN 4
                   WHEN t.trn_start_date BETWEEN '2014-07-01' AND '2015-06-30' THEN 3
                   WHEN t.trn_start_date BETWEEN '2013-07-01' AND '2014-06-30' THEN 2
                   WHEN t.trn_start_date BETWEEN '2013-02-01' AND '2013-06-30' THEN 1
                   ELSE 0 END DateGrp 
           from
              wi_training t
                 JOIN wi_indv_training wit 
                    ON t.trn_id = wit.trn_id 
                   AND wit.is_deleted = 0 
                   JOIN wi_individual_g g
                          g.ind_is_recepient = 'yes' 
                      AND g.ind_deleted = 0
                      AND wit.ind_id = g.ind_id 
                      INNER JOIN wi_individual_p p
                         ON g.ind_id = p.ind_id
                        AND p.ind_dalit='yes' 
           where
                  t.trn_beneficiary_type = 2 
              AND t.trn_deleted = 0 
              AND t.trn_start_date >= '2013-02-01'
              AND t.trn_start_date <= '2018-06-30' ) PQ
         INNER JOIN wi_district d
            ON PQ.ind_district_id = d.dst_id 
      GROUP BY 
         d.dst_name

Answer 2

我找到了將性能提高三倍的方法：

At first : the query took around 128 secs
After suggestion: the query took around 78 secs
Further modification: the query took around 23 secs
---------------------------------------------------------------------------------
SELECT d.dst_name,
COUNT(DISTINCT(CASE WHEN a.trn_start_date BETWEEN '2014-07-01' AND '2015-06-30' THEN a.ind_id END)) AS y3 , 
COUNT(DISTINCT(CASE WHEN a.trn_start_date BETWEEN '2013-07-01' AND '2014-06-30' THEN a.ind_id END)) AS y2 , 
COUNT(DISTINCT(CASE WHEN a.trn_start_date BETWEEN '2013-02-01' AND '2013-06-30' THEN a.ind_id END)) AS y1  
FROM 
(
    SELECT g.ind_district_id,g.ind_id,t.trn_start_date,t.trn_beneficiary_type
    FROM wi_individual_g g
    INNER JOIN wi_indv_training wit ON g.ind_id = wit.ind_id AND wit.is_deleted = 0 AND g.ind_deleted=0 AND g.ind_is_recepient='yes'
    INNER JOIN wi_training t ON wit.trn_id = t.trn_id AND t.trn_beneficiary_type=2 AND t.trn_deleted = 0
) a
INNER JOIN wi_individual_p p ON p.ind_id=a.ind_id
INNER JOIN wi_district d ON d.dst_id=a.ind_district_id
WHERE p.ind_dalit='yes'
GROUP BY d.dst_name;

總體而言，性能比我以前的查詢提高了6倍。 感謝您的建議@DRapp

如果有人有最好的解決方案來提高性能，我要感謝他！