[英]Can you group and count in mysql on different columns?
用戶有一個列表,其中包含不同類別的項目。 我想知道用戶在每個類別中有多少項。
User | item | category ____________________________ Bill | car | new Bill | truck | used Bill | boat | new Bill | house | old Sue | car | used Sue | truck | used Bill | bike | new Sue | viola | used
我想要結果
User category __________________________ Bill| new | 3 Bill| used | 1 Bill| sold | 1
我試過了
$SQL = "SELECT COUNT(DISTINCT CATEGORY) FROM LIST WHERE USER=Bill";
但它並沒有讓我走得很遠。
謝謝
您需要使用group by
語句:
select user, category, count(distinct item)
from mytable
where user = 'Bill'
group by user, category
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