comma separated string of selected values in mysql

问题

I want to convert selected values into a comma separated string in MySQL. My initial code is as follows:

SELECT id FROM table_level where parent_id=4;

Which produced:

'5'
'6'
'9'
'10'
'12'
'14'
'15'
'17'
'18'
'779'

My desired output would look like this:

"5,6,9,10,12,14,15,17,18,779"

回答1:

Check this

SELECT GROUP_CONCAT(id)  FROM table_level where parent_id=4 group by parent_id;

回答2:

If you have multiple rows for parent_id.

SELECT GROUP_CONCAT(id) FROM table_level where parent_id=4 GROUP BY parent_id;

If you want to replace space with comma.

SELECT REPLACE(id,' ',',') FROM table_level where parent_id=4;

回答3:

First to set group_concat_max_len, otherwise it will not give you all the result:

SET GLOBAL  group_concat_max_len = 999999;
SELECT GROUP_CONCAT(id)  FROM table_level where parent_id=4 group by parent_id;

回答4:

Use group_concat() function of mysql.

SELECT GROUP_CONCAT(id) FROM table_level where parent_id=4 GROUP BY parent_id;

It'll give you concatenated string like :

5,6,9,10,12,14,15,17,18,779 

回答5:

Try this

SELECT CONCAT('"',GROUP_CONCAT(id),'"') FROM table_level 
where parent_id=4 group by parent_id;

Result will be

 "5,6,9,10,12,14,15,17,18,779"

回答6:

Use group_concat method in mysql

回答7:

The default separator between values in a group is comma(,). To specify any other separator, use SEPARATOR as shown below.

SELECT GROUP_CONCAT(id SEPARATOR '|')
FROM `table_level`
WHERE `parent_id`=4
GROUP BY `parent_id`;

5|6|9|10|12|14|15|17|18|779

To eliminate the separator, then use SEPARATOR ''

SELECT GROUP_CONCAT(id SEPARATOR '')
FROM `table_level`
WHERE `parent_id`=4
GROUP BY `parent_id`;

Refer for more info GROUP_CONCAT

来源：https://stackoverflow.com/questions/19558443/comma-separated-string-of-selected-values-in-mysql