Question

我想多次使用子查询（它采用不同的输入）并与父查询连接。问题是，查询需要几分钟才能执行。这是优化后续查询的最佳方法。

SELECT A.PROJECT_ID,A.PROJECT_BASIC_INFORMATION_ID,B.VALUE AS BU_START_DATE,C.VALUE AS BU_DURATION,D.VALUE AS BU_AMOUNT,E.VALUE AS PLUG FROM 
PROJECT_BASIC_INFORMATION A,
CUSTOM_ATTRIBUTES_VALUES B,
CUSTOM_ATTRIBUTES_VALUES C,
CUSTOM_ATTRIBUTES_VALUES D,
CUSTOM_ATTRIBUTES_VALUES E
WHERE 
A.TENANT_ID = '100' AND
B.MAP_ID = (SELECT MST_ATTRIBUTE_ID FROM `MST_TENANT_CUSTOM_ATTRIBUTES` 
WHERE LABEL='Budget Project Savings Start Date' AND 
TENANT_ID='100') AND
C.MAP_ID = (SELECT MST_ATTRIBUTE_ID FROM `MST_TENANT_CUSTOM_ATTRIBUTES` 
WHERE LABEL='Budget Savings Duration' AND 
TENANT_ID='100') AND
D.MAP_ID = (SELECT MST_ATTRIBUTE_ID FROM `MST_TENANT_CUSTOM_ATTRIBUTES` 
WHERE LABEL='Budget Annualized Savings' AND 
TENANT_ID='100') AND
E.MAP_ID = (SELECT MST_ATTRIBUTE_ID FROM `MST_TENANT_CUSTOM_ATTRIBUTES` 
WHERE LABEL='Plug' AND 
TENANT_ID='100')

GROUP BY A.PROJECT_BASIC_INFORMATION_ID ORDER BY A.PROJECT_ID

感谢。

Answer 1

您正在使用master_attribute_id表中的所有子查询自杀。我已经改变了做JOIN的查询。从原始的“A”别名开始，然后对同一个“A.TENANT_ID”（非固定值）的每个属性表进行JOIN，但另外每个实例另外AND ... LABEL ='whatever'。因此，每个联接都按照相同的租户和标签获取自定义属性。现在，从每个中，通过MAP_ID连接到属性表。所以我的别名与“CAV”（custom_Addtribute_Values）表以及A，B，C，D相关联。因此，您只需要最外层WHERE子句中的实际租户ID。

现在，为了帮助确保查询的优化，你的MST_TENANT_CUSTOM_ATTRIBUTES表，我将有一个覆盖索引（tenant_id，label，map_id）。对于Custom_Attributes_Values表，我会有一个索引（map_id，value）

SELECT 
      A.PROJECT_ID,
      A.PROJECT_BASIC_INFORMATION_ID,
      CAV_A.VALUE AS BU_START_DATE,
      CAV_B.VALUE AS BU_DURATION,
      CAV_C.VALUE AS BU_AMOUNT,
      E.VALUE AS PLUG 
   FROM 
      PROJECT_BASIC_INFORMATION A
         JOIN MST_TENANT_CUSTOM_ATTRIBUTES MT_A
            ON A.TENANT_ID = MT_A.TENANT_ID
            AND MT_A.LABEL = 'Budget Project Savings Start Date' 
            JOIN CUSTOM_ATTRIBUTES_VALUES A
               ON MT_A.MAP_ID = CAV_A.MAP_ID

         JOIN MST_TENANT_CUSTOM_ATTRIBUTES MT_B
            ON A.TENANT_ID = MT_B.TENANT_ID
            AND MA_B.LABEL = 'Budget Savings Duration' 
            JOIN CUSTOM_ATTRIBUTES_VALUES B
               ON MT_B.MAP_ID = CAV_B.MAP_ID

         JOIN MST_TENANT_CUSTOM_ATTRIBUTES MT_C
            ON A.TENANT_ID = MT_C.TENANT_ID
            AND MA_C.LABEL = 'Budget Annualized Savings'
            JOIN CUSTOM_ATTRIBUTES_VALUES C
               ON MT_C.MAP_ID = CAV_C.MAP_ID

         JOIN MST_TENANT_CUSTOM_ATTRIBUTES MT_D
            ON A.TENANT_ID = MT_D.TENANT_ID
            AND MA_D.LABEL = 'Plug' 
            JOIN CUSTOM_ATTRIBUTES_VALUES D
               ON MT_D.MAP_ID = CAV_D.MAP_ID
   WHERE 
      A.TENANT_ID = 100
   GROUP BY 
      A.PROJECT_BASIC_INFORMATION_ID 
   ORDER BY 
      A.PROJECT_ID

Answer 2

这应该是可能的。不幸的是，没有检查它以确保它是否有效。

SELECT 
      A.PROJECT_ID,
      A.PROJECT_BASIC_INFORMATION_ID,
      IF(MT_A.LABEL='Budget Project Savings Start Date',CAV.VALUE,NULL) AS BU_START_DATE,
      IF(MT_A.LABEL='Budget Savings Duration',CAV.VALUE,NULL) AS BU_DURATION,
      IF(MT_A.LABEL='Budget Annualized Savings',CAV.VALUE,NULL) AS BU_AMOUNT,
      IF(MT_A.LABEL='Plug',CAV.VALUE,NULL) AS PLUG,
   FROM 
      PROJECT_BASIC_INFORMATION A
         JOIN MST_TENANT_CUSTOM_ATTRIBUTES MT_A
            ON A.TENANT_ID = MT_A.TENANT_ID
            AND MT_A.LABEL in ('Budget Project Savings Start Date',
                               'Budget Savings Duration',
                               'Budget Annualized Savings',
                               'Plug')
            JOIN CUSTOM_ATTRIBUTES_VALUES CAV
               ON MT_A.MAP_ID = CAV.MAP_ID
   WHERE 
      A.TENANT_ID = 100
   GROUP BY 
      A.PROJECT_ID,A.PROJECT_BASIC_INFORMATION_ID 
   ORDER BY 
      A.PROJECT_ID

多次连接同一个表

2 个答案: