can't improve query performance of query - mysql

Question

I have the following 2 tables:
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)
);
with the index:
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
);
I'm running the following query:
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';
And it takes about 2 minutes to complete.
I did EXPLAIN in order to try and improve the query performance and got the following output:
+----+-------------+------------------+------------+--------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------------------------+---------+----------------------+-------+----------+--------------------------+
| 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 |
+----+-------------+------------------+------------+--------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------------------------+---------+----------------------+-------+----------+--------------------------+
I see that I scan 71276 rows in table1 and I can't seem to make this number lower.
Is there an index I can create to improve this query performance?

Answer 1

Move ValidForBilling before MerchantCreationTime in accID_type_merchCreatTime_vfb. You need to do ref lookups =TRUE before range uses in an index.
For table 2, seems to be a table1ID index already and appending CalculatedAmount will be able to be used in the result:
CREATE INDEX tbl1IDCalcAmount (table1ID,CalculatedAmount) ON table2