mysql查詢非重復的行內容,不重復的記錄數count(distinct xx)

mysql查詢非重復的行內容,不重復的記錄數count(distinct xx)

count去重

id, p_id, p_name , p_content , p_time

1 343 aaa aaaaaa 2012-09-01

2 344 bbb bbbbbb 2012-09-02

3 321 ccc cccccccc 2012-09-03

4 343 aaa aaaaaa 2012-09-04

想查詢不重復的行的內容,並且輸出 p_sum ( 產品p_id出現重復的次數)

select  *, count(*) as p_sum from p_table_name group by p_name;

查詢不重復的行的總行數(好寫翻頁)

select count(distinct p_id) as num from p_table_name;