mysql查询不同，性能也不同

下面的问题有什么区别？ id是主键

1, select id from tbl_xxx WHERE 2708 <= id <= 1562755185;
2, select id from tbl_xxx WHERE id> = 2708 and id <= 1562755185;
3, select id from tbl_xxx WHERE id between 2708 and 1562755185;

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1，从tbl_xxx中选择id，其中2708个查询2和3是等效的，因此它们应该执行相同的操作。查询1完全不同；查询1相当于：

select id from tbl_xxx WHERE (2708 <= id) <= 1562755185;

当然，假设
id
从不为空

因此，查询是完全不同的，没有理由期望它们执行相同的操作

例如，我有一张桌子，看起来像这样：

mysql> select * from stars;
+----+-------+
| id | stars |
+----+-------+
|  1 |     1 |
|  2 |     2 |
|  3 |     3 |
|  4 |     2 |
|  5 |     1 |
|  6 |     1 |
|  7 |     1 |
|  8 |     2 |
|  9 |     1 |
+----+-------+

介于

之间的

执行以下操作：

mysql> select * from stars where id between 3 and 5;
+----+-------+
| id | stars |
+----+-------+
|  3 |     3 |
|  4 |     2 |
|  5 |     1 |
+----+-------+

mysql> select * from stars where 3 <= id <= 5;
+----+-------+
| id | stars |
+----+-------+
|  1 |     1 |
|  2 |     2 |
|  3 |     3 |
|  4 |     2 |
|  5 |     1 |
|  6 |     1 |
|  7 |     1 |
|  8 |     2 |
|  9 |     1 |
+----+-------+

但是你的
a你是如何衡量绩效的？你的结果是什么？数据库将在内部执行一些缓存，因此如果背靠背运行相同或类似的查询，第二个查询将处于优势，因为它可能会命中缓存。explain select id from tblData，其中id>=2708，id explain select id from tblData，其中2708
mysql> select * from stars where id between 3 and 5;
+----+-------+
| id | stars |
+----+-------+
|  3 |     3 |
|  4 |     2 |
|  5 |     1 |
+----+-------+

mysql> select * from stars where 3 <= id <= 5;
+----+-------+
| id | stars |
+----+-------+
|  1 |     1 |
|  2 |     2 |
|  3 |     3 |
|  4 |     2 |
|  5 |     1 |
|  6 |     1 |
|  7 |     1 |
|  8 |     2 |
|  9 |     1 |
+----+-------+