Question

我有以下2个表：

CREATE TABLE table1 (
  ID INT(11) NOT NULL AUTO_INCREMENT,
  AccountID INT NOT NULL,
  Type VARCHAR(50) NOT NULL,
  ValidForBilling BOOLEAN NULL DEFAULT false,  
  MerchantCreationTime TIMESTAMP NOT NULL,
  PRIMARY KEY (ID),
  UNIQUE KEY (OrderID, Type)
);

具有索引：
INDEX accID_type_merchCreatTime_vfb (AccountID, Type, MerchantCreationTime, ValidForBilling);

CREATE TABLE table2 (
  OrderID INT NOT NULL,
  AccountID INT NOT NULL,
  LineType VARCHAR(256) NOT NULL,
  CreationDate TIMESTAMP NOT NULL,
  CalculatedAmount NUMERIC(4,4) NULL,
  table1ID INT(11) NOT NULL
);

我正在运行以下查询：

SELECT COALESCE(SUM(CalculatedAmount), 0.0) AS CalculatedAmount
FROM table2
       INNER JOIN table1  ON table1.ID = table2.table1ID
WHERE table1.ValidForBilling is TRUE
  AND table1.AccountID = 388
  AND table1.Type = 'TPG_DISCOUNT'
  AND table1.MerchantCreationTime >= '2018-11-01T05:00:00'
  AND table1.MerchantCreationTime < '2018-12-01T05:00:00';

大约需要2分钟才能完成。
我做了EXPLAIN是为了尝试提高查询性能，并得到以下输出：

+----+-------------+------------------+------------+--------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------------------------+---------+----------------------+-------+----------+--------------------------+
| id | select_type | table            | partitions | type   | possible_keys                                                                                                                                                                                        | key                           | key_len | ref                  | rows  | filtered | Extra                    |
+----+-------------+------------------+------------+--------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------------------------+---------+----------------------+-------+----------+--------------------------+
|  1 | SIMPLE      | table1           | NULL       | range  | PRIMARY,i_fo_merchant_time_account,FO_AccountID_MerchantCreationTime,FO_AccountID_ExecutionTime,FO_AccountID_Type_ExecutionTime,FO_AccountID_Type_MerchantCreationTime,accID_type_merchCreatTime_vfb | accID_type_merchCreatTime_vfb | 61      | NULL                 | 71276 |   100.00 | Using where; Using index |
|  1 | SIMPLE      | table2           | NULL       | eq_ref | table1ID,i_oc_fo_id                                                                                                                                                                                  | table1ID                      | 4       | finance.table1.ID    |     1 |   100.00 | NULL                     |
+----+-------------+------------------+------------+--------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------------------------+---------+----------------------+-------+----------+--------------------------+

我看到我扫描了table1中的71276行，但似乎无法降低这个数字。
我可以创建一个索引来改善查询性能吗？

Answer 1

在ValidForBilling中的MerchantCreationTime之前将accID_type_merchCreatTime_vfb移动。您需要在范围用于索引之前进行引用查询=TRUE。

对于表2，似乎已经是一个table1ID索引，并且可以在结果中添加CalculatedAmount：

CREATE INDEX tbl1IDCalcAmount (table1ID,CalculatedAmount) ON table2

无法提高查询的查询性能

1 个答案: