count(*) 與 group by一起使用的問(wèn)題

we_2002

mysql> SELECT COUNT(*) FROM Bird GROUP BY name;
+---------+----------+
| COUNT(*) |
+---------+----------+
|         2 |
|        1 |
+---------+----------+
2 rows in set (0.00 sec)

但是我的原意是想計(jì)算出Bird這個(gè)表中不重復(fù)name的行的總數(shù),期望輸出如下
+---------+----------+
| COUNT(*) |
+---------+----------+
|         3 |
+---------+----------+
1 rows in set (0.00 sec)

嘗試使用了子查詢:
SELECT COUNT(*) AS `Count` FROM( SELECT * FROM Bird GROUP BY name) AS `Temp`
但是在數(shù)據(jù)量稍大的情況下查詢效果實(shí)在是慢到不能接受了

請(qǐng)教一下大家這個(gè)要怎么寫(xiě)法?

wildlily980

select count(distinct name) from Bird

we_2002

但是我還要加上其他的where查詢條件的話好像就不行了
SELECT Count(distinct `Name`) FROM `db_live_channel` WHERE `Name` LIKE '%re%' GROUP BY `Name`

sunnyfun

SELECT Count(distinct `Name`) FROM `db_live_channel` GROUP BY `Name` HAVING `Name` LIKE '%re%'

不過(guò)就算能運(yùn)行也沒(méi)效率可言的