mysql的where条件中的字段不要加函数

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root@10.10.10.10 (mac) > show create table apple\G
*************************** 1. row ***************************
       Table: apple
Create Table: CREATE TABLE `apple` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `cluster_name` varchar(64) NOT NULL,
  `queue_name` varchar(128) NOT NULL,
  `time` datetime NOT NULL,
  `apps` int(11) NOT NULL,
  `numapps` int(11) NOT NULL,
  `maxApps` int(11) NOT NULL,
  `used_resource` int(11) NOT NULL,
  `expected_share` int(11) NOT NULL,
  `max_resource` int(11) NOT NULL,
  `used_resource_memory` int(11) NOT NULL,
  `expected_memory` int(11) NOT NULL,
  `max_memory` int(11) NOT NULL,
  PRIMARY KEY (`id`),
  KEY `time` (`time`)
) ENGINE=InnoDB AUTO_INCREMENT=218408440 DEFAULT CHARSET=utf8
1 row in set (0.14 sec)

Wed Jun 23 14:30:00 2021
root@10.10.10.10 (mac) > select count(*) from apple;
+-----------+
| count(*)  |
+-----------+
| 157898648 |
+-----------+
1 row in set (41.96 sec)

Wed Jun 23 14:30:53 2021
root@10.10.10.10 (mac) > desc SELECT queue_name, AVG(used_resource) 

FROM apple 

WHERE cluster_name='azmbcommonprc-hadoop' 

AND DATE(time) >='2021-06-22 00:00:00' 

AND DATE(time) <= '2021-06-22 23:59:59' 

GROUP BY queue_name;
+----+-------------+---------+------------+------+---------------+------+---------+------+-----------+----------+----------------------------------------------+
| id | select_type | table   | partitions | type | possible_keys | key  | key_len | ref  | rows      | filtered | Extra                                        |
+----+-------------+---------+------------+------+---------------+------+---------+------+-----------+----------+----------------------------------------------+
|  1 | SIMPLE      | apple | NULL       | ALL  | NULL          | NULL | NULL    | NULL | 156586044 |    10.00 | Using where; Using temporary; Using filesort |
+----+-------------+---------+------------+------+---------------+------+---------+------+-----------+----------+----------------------------------------------+
1 row in set, 1 warning (0.14 sec)

Wed Jun 23 14:31:58 2021


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#####################：下面将time字段上的date函数去掉，则sql优化效果明显：


root@10.10.10.10 (mac) > desc SELECT queue_name, AVG(used_resource) 

FROM apple 

WHERE cluster_name='azmbcommonprc-hadoop' 

AND time >= '2021-06-22 00:00:00' 

AND time <= '2021-06-22 23:59:59' 

GROUP BY queue_name;
+----+-------------+---------+------------+-------+---------------+------+---------+------+--------+----------+---------------------------------------------------------------------+
| id | select_type | table   | partitions | type  | possible_keys | key  | key_len | ref  | rows   | filtered | Extra                                                               |
+----+-------------+---------+------------+-------+---------------+------+---------+------+--------+----------+---------------------------------------------------------------------+
|  1 | SIMPLE      | apple | NULL       | range | time          | time | 5       | NULL | 231088 |    10.00 | Using index condition; Using where; Using temporary; Using filesort |
+----+-------------+---------+------------+-------+---------------+------+---------+------+--------+----------+---------------------------------------------------------------------+
1 row in set, 1 warning (0.14 sec)

Wed Jun 23 14:32:05 2021
root@10.10.10.10 (mac) > select * from apple limit 1\G;
*************************** 1. row ***************************
                     id: 1
           cluster_name: azmbcommonprc-hadoop
             queue_name: root
                   time: 2018-03-15 19:39:57
          apps: 0
         numapps: 0
                maxApps: 700
     used_resource: 0
expected_share: 15
      max_resource: 324
     used_resource_memory: 0
expected_memory: 30720
      max_memory: 552960
1 row in set (0.14 sec)

ERROR: 
No query specified

Wed Jun 23 14:32:25 2021
root@10.10.10.10 (mac) >

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