CREATE TABLE t1 (id INT ,rank INT, log_time DATETIME, nickname VARCHAR(64)) ENGINE INNODB; ALTER TABLE t1 ADD PRIMARY KEY (id), ADD KEY idx_rank (rank),ADD KEY idx_log_time (log_time);
mysql> select count(*) from t1; +----------+ | count(*) | +----------+ | 5000 | +----------+ 1 row in set (0.00 sec)
mysql> SELECT * FROM t1 WHERE DATE(log_time) = ‘2015-04-09‘\G *************************** 1. row *************************** id: 95 rank: 24 log_time: 2015-04-09 05:53:13 nickname: test *************************** 2. row *************************** id: 3423 rank: 42 log_time: 2015-04-09 02:55:38 nickname: test 2 rows in set (0.01 sec)
mysql> explain SELECT * FROM t1 WHERE DATE(log_time) = ‘2015-04-09‘\G *************************** 1. row *************************** id: 1 select_type: SIMPLE table: t1 partitions: NULL type: ALL possible_keys: NULL key: NULL key_len: NULL ref: NULL rows: 5000 filtered: 100.00 Extra: Using where 1 row in set, 1 warning (0.00 sec)
mysql> SELECT * FROM t1 WHERE log_time >= ‘2015-04-09 00:00:00‘ AND log_time <=‘2015-04-10 00:00:00‘\G *************************** 1. row *************************** id: 3423 rank: 42 log_time: 2015-04-09 02:55:38 nickname: test *************************** 2. row *************************** id: 95 rank: 24 log_time: 2015-04-09 05:53:13 nickname: test 2 rows in set (0.00 sec)
mysql> explain SELECT * FROM t1 WHERE log_time >= ‘2015-04-09 00:00:00‘ AND log_time <= ‘2015-04-10 00:00:00‘\G *************************** 1. row *************************** id: 1 select_type: SIMPLE table: t1 partitions: NULL type: range possible_keys: idx_log_time key: idx_log_time key_len: 6 ref: NULL rows: 2 filtered: 100.00 Extra: Using index condition 1 row in set, 1 warning (0.00 sec)
ALTER TABLE t1 ADD COLUMN log_date DATE AS (DATE(log_Time)) stored, ADD KEY idx_log_date (log_date);
mysql> SELECT * FROM t1 WHERE log_date = ‘2015-04-09‘\G *************************** 1. row *************************** id: 95 rank: 24 log_time: 2015-04-09 05:53:13 nickname: test log_date: 2015-04-09 *************************** 2. row *************************** id: 3423 rank: 42 log_time: 2015-04-09 02:55:38 nickname: test log_date: 2015-04-09 2 rows in set (0.00 sec)
mysql> explain SELECT * FROM t1 WHERE log_date = ‘2015-04-09‘\G *************************** 1. row *************************** id: 1 select_type: SIMPLE table: t1 partitions: NULL type: ref possible_keys: idx_log_date key: idx_log_date key_len: 4 ref: const rows: 2 filtered: 100.00 Extra: NULL 1 row in set, 1 warning (0.00 sec)
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原文地址:http://blog.csdn.net/yueliangdao0608/article/details/49815409