需要一個唯一的列到現有的查詢

Question

我有一個日誌表在MySQL中，看起來像這樣：

table1 

id client_id country result 
------------------------------- 
1 323323  US  escalated 

我當前的查詢是：

select country, count(country) as country_total 
    FROM table1 
    WHERE result = 'escalated' 
    GROUP BY country 
    ORDER BY country_total 
    DESC LIMIT 5 

結果（這正是我想要的）是：

$VAR1 = [ 
     { 
     'country' => 'US', 
     'country_total' => '30' 
     }, 
     { 
     'country' => 'CN', 
     'country_total' => '19' 
     }, 
     { 
     'country' => 'DE', 
     'country_total' => '10' 
     } 
    ]; 

然而，在日誌表client_ids可以有重複，我不想在我的結果集中的重複。我怎樣才能做到這一點？

Answer 1

使用distinct

SELECT country, count(distinct client_id) as country_total 
FROM table1 
WHERE result = 'escalated' 
GROUP BY country 
ORDER BY country_total 
DESC LIMIT 5