从表中选择随机但不同的行-MySQL

Question

I have a table with various categories, and multiple entries for each category.

Word    |  Category  
------------------  
Apple   |  Food  
Orange  |  Food  
Grapes  |  Food  
Mango   |  Food  

I wish to retrieve 3 random rows for the category 'food', for which I run the following query,

$query = "SELECT * FROM table WHERE category='food' ORDER BY RAND() LIMIT 3"

$fetch_row = mysqli_query($db_connect, $query);
        while ($row = mysqli_fetch_array($fetch_row)) {
            array_push($words, $row['word']);
        }

However, when I print the contents of the array $words, they tend to repeat sometimes (not on all runs), for example;

Apple, Orange, Apple

ie Its not always unique. I want to select random, yet unique words for a given category. What am I doing wrong? I've tried going through other related answers, but I keep messing something up. I've also tried the following query;

SELECT * FROM table WHERE category='food' GROUP BY category ORDER BY RAND() LIMIT 3

But this still gives repetitions occasionally.

Answer 1

由于word列具有相同的值，因此请按以下方式对GROUP BY word分组：

SELECT * FROM table WHERE category='food' GROUP BY word LIMIT 3