root:optimizetest>EXPLAIN select COUNT(name1) from demo1\G
*************************** 1. row ***************************
id: 1
select_type: SIMPLE
table: demo1
type: index
possible_keys: NULL
key: PRIMARY
key_len: 4
ref: NULL
rows: 2983
Extra: Using index
1 row in set (0.00 sec)root:optimizetest>select COUNT(name1) from demo1;
+--------------+
| COUNT(name1) |
+--------------+
| 3147 |
+--------------+
1 row in set (0.00 sec)root:optimizetest>看第一个explain select 里面只扫描了2983行数据.
但是我的count(name1) 里面为什么可以查到3147条语句呢?
请问这多的100多条记录是怎么来的?
那么说 rows: 2983 没有实际意义?··