如何将SQL不同的查询结果连接成一个字符串？

Question

How to get the distinct values from a column and concatenate them into one string? Thanks.

For example, I have a column like

fruit_name
------
apple
apple
apple
banana
orange
orange
.
.
.

I want to create a result like apple, banana, orange...

Here is the query I have tried but it will only give a result of apple, apple, apple, banana...

SELECT LISTAGG(fruit_name,', ') WITHIN GROUP (ORDER BY fruit_name) "fruit_List" FROM FRUIT_TABLE;

I have no idea how to make the result distinct.

Answer 1

You can use the MySQL GROUP_CONCAT() function to solve your problem:

SELECT GROUP_CONCAT(t.fn)
FROM
(
    SELECT fruit_name fn
    FROM FRUIT_TABLE
    GROUP BY fruit_name
) t

The default separator in GROUP_CONCAT is a comma, which is what you specified in your original problem.

Update:

I give credit for this solution to @cars10 who pointed out that everyone initially got this wrong.

Answer 2

试试这个查询，

SELECT GROUP_CONCAT(DISTINCT fruit_name) FROM FRUIT_TABLE ORDER BY fruit_name;

Answer 3

You can use the following query using GROUP_CONCAT since LISTAGG is not available in mysql:

SELECT GROUP_CONCAT(DISTINCT fruit_name ORDER BY fruit_name ASC SEPARATOR ',') as fruit_List
FROM FRUIT_TABLE

GROUP_CONCAT has DISTINCT and ORDER BY attributes included

Answer 4

edit: (my first version was plainly wrong!)

select group_concat(fn) fruit_list
from (select fruit_name fn 
         from fruit_table 
         group by fruit_name) fruits

Now it works, see here: http://sqlfiddle.com/#!9/bfbf4/2 but Nikhil Batra's solution is clearly a better choice!