Question

下面的查询需要很长时间，我正在尝试调整查询，但似乎无法正常工作。无论如何，我可以重写查询。请帮我调整查询。

 SELECT DISTINCT TC.V_ID,A.ID,A.NAME 
    FROM OM_A_DATA TC 
       INNER JOIN ACC_DOM_EXT AE ON TC.DOMAINS = AE.DOMAIN
        LEFT OUTER JOIN ACCOUNT A ON A.ID=AE.ACCOUNTID
    WHERE V_ID not in (select distinct V_ID from DATA_ACC_MAP)


OM_A_DATA  has 41,696,776 rows
ACC_DOM_EXT has 106,725 rows
ACCOUNT has 106731 rows
DATA_ACC_MAP has 91021 rows

Answer 1

not exists通常比not in更好：

SELECT DISTINCT TC.V_ID, A.ID, A.NAME 
FROM OM_A_DATA TC INNER JOIN
     ACC_DOM_EXT AE
     ON TC.DOMAINS = AE.DOMAIN LEFT OUTER JOIN
     ACCOUNT A
     ON A.ID = AE.ACCOUNTID
WHERE NOT EXISTS (SELECT 1 FROM DATA_ACC_MAP dam WHERE dam.V_ID = tc.V_ID );

显然，你应该在DATA_ACC_MAP(V_ID)上有一个索引。您还应该在其他列上包含索引：OM_A_DATA(V_ID, DOMAINS)，ACC_DOM_EXT(DOMAIN, ACCOUNTID)和ACCOUNT(ID, NAME)。

Answer 2

删除DISTINCT。

SELECT DISTINCT TC.V_ID, A.ID, A.NAME 
FROM OM_A_DATA TC 
INNER JOIN ACC_DOM_EXT AE ON TC.DOMAINS = AE.DOMAIN
LEFT OUTER JOIN ACCOUNT A ON A.ID = AE.ACCOUNTID
WHERE V_ID NOT IN (SELECT V_ID FROM DATA_ACC_MAP)

或使用INNER JOIN而不是子查询。

SELECT DISTINCT TC.V_ID, A.ID, A.NAME 
FROM OM_A_DATA TC 
INNER JOIN ACC_DOM_EXT AE ON TC.DOMAINS = AE.DOMAIN
INNER JOIN DATA_ACC_MAP AD ON TC.V_ID != AD.V_ID 
LEFT OUTER JOIN ACCOUNT A ON A.ID = AE.ACCOUNTID

或使用LEFT JOIN而不是子查询和更改的WHERE子句。

SELECT DISTINCT TC.V_ID, A.ID, A.NAME 
FROM OM_A_DATA TC 
INNER JOIN ACC_DOM_EXT AE ON TC.DOMAINS = AE.DOMAIN
LEFT JOIN DATA_ACC_MAP AD ON TC.V_ID = AD.V_ID 
LEFT OUTER JOIN ACCOUNT A ON A.ID = AE.ACCOUNTID
WHERE AD.V_ID IS NULL

SQL Query需要很长时间

2 个答案: