臃肿的 UNION ALL 代码 (MYSQL)

Posted 2023-03-24

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【中文标题】臃肿的 UNION ALL 代码 (MYSQL)【英文标题】：Bloated UNION ALL code (MYSQL) 【发布时间】：2017-01-12 19:44:34 【问题描述】：

我是自学 SQL 的，我有一些非常慢的杂乱代码。我在 Tableau 中可视化这些数据，我创建的视图变得如此缓慢，以至于我不得不创建一个包含我需要的所有信息的表（每天刷新）。

我认为速度缓慢是由于我在这里执行了大量的 UNION ALL 语句。我这样做是为了“透视”数据，因此每个问题都不是数据库中自己的列，而是每一行的属性。

谁能提供一些关于如何重组代码以加快速度的提示？任何帮助或批评将不胜感激，谢谢！（以下只是我的代码片段，UNION ALL 块的数量还在继续......

CREATE ALGORITHM=UNDEFINED 
DEFINER=root@localhost 
SQL SECURITY DEFINER 
VIEW view_data435386_xxxxx_MASTER AS


SELECT _data435386_xxxxx_1_job_profile.ID AS ID,
_data435386_xxxxx_1_job_profile.ID AS Comment_Photos_ID,
'Job Profile' AS Impact_Area,
_data435386_xxxxx_1_job_profile.PARENT_RECORD_ID AS PARENT_RECORD_ID,
_data435386_xxxxx_1_job_profile.pjq1 AS PJQ1,
_data435386_xxxxx_1_job_profile.pjq_2 AS PJQ2,
_data435386_xxxxx_1_job_profile.pjq_3 AS PJQ3,
_data435386_xxxxx_1_job_profile.pjq_4 AS PJQ4,
_data435386_xxxxx_1_job_profile.pjq_5 AS PJQ5,
_data435386_xxxxx_1_job_profile.pjq_6 AS PJQ6,
_data435386_xxxxx_1_job_profile.pjq_7 AS PJQ7,
_data435386_xxxxx_1_job_profile.pjq_8 AS PJQ8,
_data435386_xxxxx_1_job_profile.pjq_9 AS PJQ9,
_data435386_xxxxx_1_job_profile.pjq_10 AS PJQ10,
_data435386_xxxxx_main_form.additional_comments AS Additional_Comments,
_data435386_xxxxx_main_form.wr_,
NULL AS Completion_Due_Date,
NULL AS Completion_Due_Date_1443,
NULL AS Training_Needed,
NULL AS Follow_Up_Description,
REPLACE(_data435386_xxxxx_main_form.inspector, '_', ' ') AS Inspector,
REPLACE(_data435386_xxxxx_main_form.crew_leader, '_', ' ') AS Crew_Leader,
_data435386_xxxxx_main_form.date1 AS date1,
REPLACE(_data435386_xxxxx_1_job_profile.district, '_', ' ') AS District,
REPLACE(_data435386_xxxxx_1_job_profile.division, '_', ' ') AS Division,
REPLACE(_data435386_xxxxx_1_job_profile.contractor_inspected, '_', ' ') AS Contractor_Inspected,
301 Sample_Size_Req,
        (CASE
            WHEN
                (_data435386_xxxxx_1_job_profile.division = 'xxxxx')
            THEN
                38197
            WHEN
                (_data435386_xxxxx_1_job_profile.division = 'xxxxx')
            THEN
                3734
            WHEN
                (_data435386_xxxxx_1_job_profile.division = 'xxxxx')
            THEN
                5044
            WHEN
                (_data435386_xxxxx_1_job_profile.division = 'xxxxx')
            THEN
                55214
            WHEN
                (_data435386_xxxxx_1_job_profile.division = 'xxxxx')
            THEN
                37742
            ELSE NULL   
        END) AS Population_size,
'1_Job Profile' AS Results,
3438545 AS Parent_Page_ID,
'1.0 Job Profile' AS Task,
'1.0 Job Profile' AS Construction_Activity,
NULL AS Overall_Rating,
CONCAT('https://xxxxx.xxxxx.com/exzact/dataPDF.php?TABLE_NAME=_data435386_xxxxx_main_form&ID=',
                `_data435386_xxxxx_main_form`.`ID`,
                '&PAGE_ID=3438731&USERNAME=xxxxx1&PASSWORD=xxxxx') AS `report_url`
FROM
(_data435386_xxxxx_main_form 
LEFT JOIN _data435386_xxxxx_1_job_profile ON((_data435386_xxxxx_main_form.ID = _data435386_xxxxx_1_job_profile.PARENT_RECORD_ID)))
UNION ALL 


SELECT _data435386_xxxxx_1_job_profile.ID AS ID,
_data435386_xxxxx_1_job_profile.ID AS Comment_Photos_ID,
'Safety' AS Impact_Area,
_data435386_xxxxx_1_job_profile.PARENT_RECORD_ID AS PARENT_RECORD_ID,
_data435386_xxxxx_1_job_profile.pjq1 AS PJQ1,
_data435386_xxxxx_1_job_profile.pjq_2 AS PJQ2,
_data435386_xxxxx_1_job_profile.pjq_3 AS PJQ3,
_data435386_xxxxx_1_job_profile.pjq_4 AS PJQ4,
_data435386_xxxxx_1_job_profile.pjq_5 AS PJQ5,
_data435386_xxxxx_1_job_profile.pjq_6 AS PJQ6,
_data435386_xxxxx_1_job_profile.pjq_7 AS PJQ7,
_data435386_xxxxx_1_job_profile.pjq_8 AS PJQ8,
_data435386_xxxxx_1_job_profile.pjq_9 AS PJQ9,
_data435386_xxxxx_1_job_profile.pjq_10 AS PJQ10,
_data435386_xxxxx_main_form.additional_comments AS Additional_Comments,
_data435386_xxxxx_main_form.wr_,
NULL AS Completion_Due_Date,
NULL AS Completion_Due_Date_1443,
NULL AS Training_Needed,
NULL AS Follow_Up_Description,
REPLACE(_data435386_xxxxx_main_form.inspector, '_', ' ') AS Inspector,
REPLACE(_data435386_xxxxx_main_form.crew_leader, '_', ' ') AS Crew_Leader,
_data435386_xxxxx_main_form.date1 AS date1,
REPLACE(_data435386_xxxxx_1_job_profile.district, '_', ' ') AS District,
REPLACE(_data435386_xxxxx_1_job_profile.division, '_', ' ') AS Division,
REPLACE(_data435386_xxxxx_1_job_profile.contractor_inspected, '_', ' ') AS Contractor_Inspected,
301 Sample_Size_Req,
        (CASE
            WHEN
                (_data435386_xxxxx_1_job_profile.division = 'xxxxx')
            THEN
                38197
            WHEN
                (_data435386_xxxxx_1_job_profile.division = 'xxxxx')
            THEN
                3734
            WHEN
                (_data435386_xxxxx_1_job_profile.division = 'xxxxx')
            THEN
                5044
            WHEN
                (_data435386_xxxxx_1_job_profile.division = 'xxxxx')
            THEN
                55214
            WHEN
                (_data435386_xxxxx_1_job_profile.division = 'xxxxx')
            THEN
                37742
            ELSE NULL   
        END) AS Population_size,
21_Uses_proper_ppe AS Results,
3438623 AS Parent_Page_ID,
'2.1 Uses Proper PPE' AS Task,
'2.0 Safety' AS Construction_Activity,
NULL AS Overall_Rating,
CONCAT('https://xxxxx.xxxxx.com/exzact/dataPDF.php?TABLE_NAME=_data435386_xxxxx_main_form&ID=',
                `_data435386_xxxxx_main_form`.`ID`,
                '&PAGE_ID=3438731&USERNAME=xxxxx1&PASSWORD=xxxxx') AS `report_url`
FROM
((_data435386_xxxxx_main_form 
LEFT JOIN view_data435386_xxxxx_2_task_successful ON((_data435386_xxxxx_main_form.ID = view_data435386_xxxxx_2_task_successful.PARENT_RECORD_ID))) 
LEFT JOIN _data435386_xxxxx_1_job_profile ON((_data435386_xxxxx_main_form.ID = _data435386_xxxxx_1_job_profile.PARENT_RECORD_ID)))
WHERE 21_Uses_proper_ppe IS NOT NULL
UNION ALL 





SELECT _data435386_xxxxx_1_job_profile.ID AS ID,
view_data435386_xxxxx_2_task_successful.ID AS Comment_Photos_ID,
'Safety' AS Impact_Area,
_data435386_xxxxx_1_job_profile.PARENT_RECORD_ID AS PARENT_RECORD_ID,
_data435386_xxxxx_1_job_profile.pjq1 AS PJQ1,
_data435386_xxxxx_1_job_profile.pjq_2 AS PJQ2,
_data435386_xxxxx_1_job_profile.pjq_3 AS PJQ3,
_data435386_xxxxx_1_job_profile.pjq_4 AS PJQ4,
_data435386_xxxxx_1_job_profile.pjq_5 AS PJQ5,
_data435386_xxxxx_1_job_profile.pjq_6 AS PJQ6,
_data435386_xxxxx_1_job_profile.pjq_7 AS PJQ7,
_data435386_xxxxx_1_job_profile.pjq_8 AS PJQ8,
_data435386_xxxxx_1_job_profile.pjq_9 AS PJQ9,
_data435386_xxxxx_1_job_profile.pjq_10 AS PJQ10,
_data435386_xxxxx_main_form.additional_comments AS Additional_Comments,
_data435386_xxxxx_main_form.wr_,
NULL AS Completion_Due_Date,
NULL AS Completion_Due_Date_1443,
NULL AS Training_Needed,
NULL AS Follow_Up_Description,
REPLACE(_data435386_xxxxx_main_form.inspector, '_', ' ') AS Inspector,
REPLACE(_data435386_xxxxx_main_form.crew_leader, '_', ' ') AS Crew_Leader,
_data435386_xxxxx_main_form.date1 AS date1,
REPLACE(_data435386_xxxxx_1_job_profile.district, '_', ' ') AS District,
REPLACE(_data435386_xxxxx_1_job_profile.division, '_', ' ') AS Division,
REPLACE(_data435386_xxxxx_1_job_profile.contractor_inspected, '_', ' ') AS Contractor_Inspected,
301 Sample_Size_Req,
        (CASE
            WHEN
                (_data435386_xxxxx_1_job_profile.division = 'xxxxx')
            THEN
                38197
            WHEN
                (_data435386_xxxxx_1_job_profile.division = 'xxxxx')
            THEN
                3734
            WHEN
                (_data435386_xxxxx_1_job_profile.division = 'xxxxx')
            THEN
                5044
            WHEN
                (_data435386_xxxxx_1_job_profile.division = 'xxxxx')
            THEN
                55214
            WHEN
                (_data435386_xxxxx_1_job_profile.division = 'xxxxx')
            THEN
                37742
            ELSE NULL   
        END) AS Population_size,
22_Damage_Prevention AS Results,
3438623 AS Parent_Page_ID,
'2.2 Damage Prevention' AS Task,
'2.0 Safety' AS Construction_Activity,
NULL AS Overall_Rating,
CONCAT('https://xxxxx.xxxxx.com/exzact/dataPDF.php?TABLE_NAME=_data435386_xxxxx_main_form&ID=',
                `_data435386_xxxxx_main_form`.`ID`,
                '&PAGE_ID=3438731&USERNAME=xxxxx1&PASSWORD=xxxxx') AS `report_url`
FROM
((_data435386_xxxxx_main_form 
LEFT JOIN view_data435386_xxxxx_2_task_successful ON((_data435386_xxxxx_main_form.ID = view_data435386_xxxxx_2_task_successful.PARENT_RECORD_ID))) 
LEFT JOIN _data435386_xxxxx_1_job_profile ON((_data435386_xxxxx_main_form.ID = _data435386_xxxxx_1_job_profile.PARENT_RECORD_ID)))
WHERE 22_Damage_Prevention IS NOT NULL
UNION ALL 





SELECT _data435386_xxxxx_1_job_profile.ID AS ID,
view_data435386_xxxxx_2_task_successful.ID AS Comment_Photos_ID,
'Safety' AS Impact_Area,
_data435386_xxxxx_1_job_profile.PARENT_RECORD_ID AS PARENT_RECORD_ID,
_data435386_xxxxx_1_job_profile.pjq1 AS PJQ1,
_data435386_xxxxx_1_job_profile.pjq_2 AS PJQ2,
_data435386_xxxxx_1_job_profile.pjq_3 AS PJQ3,
_data435386_xxxxx_1_job_profile.pjq_4 AS PJQ4,
_data435386_xxxxx_1_job_profile.pjq_5 AS PJQ5,
_data435386_xxxxx_1_job_profile.pjq_6 AS PJQ6,
_data435386_xxxxx_1_job_profile.pjq_7 AS PJQ7,
_data435386_xxxxx_1_job_profile.pjq_8 AS PJQ8,
_data435386_xxxxx_1_job_profile.pjq_9 AS PJQ9,
_data435386_xxxxx_1_job_profile.pjq_10 AS PJQ10,
_data435386_xxxxx_main_form.additional_comments AS Additional_Comments,
_data435386_xxxxx_main_form.wr_,
NULL AS Completion_Due_Date,
NULL AS Completion_Due_Date_1443,
NULL AS Training_Needed,
NULL AS Follow_Up_Description,
REPLACE(_data435386_xxxxx_main_form.inspector, '_', ' ') AS Inspector,
REPLACE(_data435386_xxxxx_main_form.crew_leader, '_', ' ') AS Crew_Leader,
_data435386_xxxxx_main_form.date1 AS date1,
REPLACE(_data435386_xxxxx_1_job_profile.district, '_', ' ') AS District,
REPLACE(_data435386_xxxxx_1_job_profile.division, '_', ' ') AS Division,
REPLACE(_data435386_xxxxx_1_job_profile.contractor_inspected, '_', ' ') AS Contractor_Inspected,
301 Sample_Size_Req,
        (CASE
            WHEN
                (_data435386_xxxxx_1_job_profile.division = 'xxxxx')
            THEN
                38197
            WHEN
                (_data435386_xxxxx_1_job_profile.division = 'xxxxx')
            THEN
                3734
            WHEN
                (_data435386_xxxxx_1_job_profile.division = 'xxxxx')
            THEN
                5044
            WHEN
                (_data435386_xxxxx_1_job_profile.division = 'xxxxx')
            THEN
                55214
            WHEN
                (_data435386_xxxxx_1_job_profile.division = 'xxxxx')
            THEN
                37742
            ELSE NULL   
        END) AS Population_size,
23_fire_bottle_and_no_smoking_sign AS Results,
3438623 AS Parent_Page_ID,
'2.3 Fire Bottle and No Smoking Sign' AS Task,
'2.0 Safety' AS Construction_Activity,
NULL AS Overall_Rating,
CONCAT('https://xxxxx.xxxxx.com/exzact/dataPDF.php?TABLE_NAME=_data435386_xxxxx_main_form&ID=',
                `_data435386_xxxxx_main_form`.`ID`,
                '&PAGE_ID=3438731&USERNAME=xxxxx1&PASSWORD=xxxxx') AS `report_url`
FROM
((_data435386_xxxxx_main_form 
LEFT JOIN view_data435386_xxxxx_2_task_successful ON((_data435386_xxxxx_main_form.ID = view_data435386_xxxxx_2_task_successful.PARENT_RECORD_ID))) 
LEFT JOIN _data435386_xxxxx_1_job_profile ON((_data435386_xxxxx_main_form.ID = _data435386_xxxxx_1_job_profile.PARENT_RECORD_ID)))
WHERE 23_fire_bottle_and_no_smoking_sign IS NOT NULL
UNION ALL 





SELECT _data435386_xxxxx_1_job_profile.ID AS ID,
view_data435386_xxxxx_2_task_successful.ID AS Comment_Photos_ID,
'Safety' AS Impact_Area,
_data435386_xxxxx_1_job_profile.PARENT_RECORD_ID AS PARENT_RECORD_ID,
_data435386_xxxxx_1_job_profile.pjq1 AS PJQ1,
_data435386_xxxxx_1_job_profile.pjq_2 AS PJQ2,
_data435386_xxxxx_1_job_profile.pjq_3 AS PJQ3,
_data435386_xxxxx_1_job_profile.pjq_4 AS PJQ4,
_data435386_xxxxx_1_job_profile.pjq_5 AS PJQ5,
_data435386_xxxxx_1_job_profile.pjq_6 AS PJQ6,
_data435386_xxxxx_1_job_profile.pjq_7 AS PJQ7,
_data435386_xxxxx_1_job_profile.pjq_8 AS PJQ8,
_data435386_xxxxx_1_job_profile.pjq_9 AS PJQ9,
_data435386_xxxxx_1_job_profile.pjq_10 AS PJQ10,
_data435386_xxxxx_main_form.additional_comments AS Additional_Comments,
_data435386_xxxxx_main_form.wr_,
NULL AS Completion_Due_Date,
NULL AS Completion_Due_Date_1443,
NULL AS Training_Needed,
NULL AS Follow_Up_Description,
REPLACE(_data435386_xxxxx_main_form.inspector, '_', ' ') AS Inspector,
REPLACE(_data435386_xxxxx_main_form.crew_leader, '_', ' ') AS Crew_Leader,
_data435386_xxxxx_main_form.date1 AS date1,
REPLACE(_data435386_xxxxx_1_job_profile.district, '_', ' ') AS District,
REPLACE(_data435386_xxxxx_1_job_profile.division, '_', ' ') AS Division,
REPLACE(_data435386_xxxxx_1_job_profile.contractor_inspected, '_', ' ') AS Contractor_Inspected,
NULL Sample_Size_Req,
        (CASE
            WHEN
                (_data435386_xxxxx_1_job_profile.division = 'xxxxx')
            THEN
                38197
            WHEN
                (_data435386_xxxxx_1_job_profile.division = 'xxxxx')
            THEN
                3734
            WHEN
                (_data435386_xxxxx_1_job_profile.division = 'xxxxx')
            THEN
                5044
            WHEN
                (_data435386_xxxxx_1_job_profile.division = 'xxxxx')
            THEN
                55214
            WHEN
                (_data435386_xxxxx_1_job_profile.division = 'xxxxx')
            THEN
                37742
            ELSE NULL   
        END) AS Population_size,
24_traffic_control_plan AS Results,
3438623 AS Parent_Page_ID,
'2.4 Traffic Control Plan' AS Task,
'2.0 Safety' AS Construction_Activity,
NULL AS Overall_Rating,
CONCAT('https://xxxxx.xxxxx.com/exzact/dataPDF.php?TABLE_NAME=_data435386_xxxxx_main_form&ID=',
                `_data435386_xxxxx_main_form`.`ID`,
                '&PAGE_ID=3438731&USERNAME=xxxxx1&PASSWORD=xxxxx') AS `report_url`
FROM
((_data435386_xxxxx_main_form 
LEFT JOIN view_data435386_xxxxx_2_task_successful ON((_data435386_xxxxx_main_form.ID = view_data435386_xxxxx_2_task_successful.PARENT_RECORD_ID))) 
LEFT JOIN _data435386_xxxxx_1_job_profile ON((_data435386_xxxxx_main_form.ID = _data435386_xxxxx_1_job_profile.PARENT_RECORD_ID)))
WHERE 24_traffic_control_plan IS NOT NULL
UNION ALL

【问题讨论】：

UNIONs 通常不是特别需要性能，因为它们只不过是将一个结果集附加到另一个结果集；你最好看看被联合的查询的性能。请突出选择之间的差异。 【参考方案1】：

看起来有几个被 UNIONed 的查询几乎相同，并且只用于生成具有不同 Results 和 Task 字段的多个结果行；您可能希望考虑合并这些查询，或将查询的统一（Results 字段的所有值作为单独的字段）版本插入中间（伪临时）表，然后针对该表合并更简单的查询。

“中间（伪临时）”是指您不打算保留的非临时表；我建议使用 TEMPORARY 表，但 mysql 不允许在同一个查询中多次引用（例如 UNION 或 self-JOIN）。

编辑：也不清楚Result 值来自哪个表；如果它们不是来自 _data435386_xxxxx_main_form，那么您有一些可以是 INNER JOIN 的 LEFT JOIN。

【讨论】：

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