mysql query and while loop creating a special string

Question

I am working on a project where I need to achieve a special task like this.

I have a sql query which fetches all the ids of users who commented on a post and then I use mysql_fetch_array and while loop to create a string of comma separated ids of those users like this.

If the ids of the users on any post are 1 and 4 and 5 and 18 and 88, the string I get is like 1,4,5,18,88.

But the problem is that if any person has made more than one comment then his/her id is added again I do not want this.

Like the users are:

1,4,5,4,1,15

It gets:

1,4,5,4,1,15

But I want:

1,4,5,15

I don't want duplicates.

What I tried:

select id from table where comment !=''
mysql_fetch_array()
while (){
   // now joining the ids of commenters here but not duplicate ids
}

Try select DISTINCT id from table where comment !='' ORDER BY id — M Khalid Junaid
– M Khalid Junaid, Commented Aug 12, 2014 at 5:15

Jha · Accepted Answer · 2014-08-12 05:22:31Z

2

Try this code

SELECT DISTINCT id FROM tablename WHERE  comment !='' ORDER BY id

It will give you the distinct id from your table

answered Aug 12, 2014 at 5:22

Jha

231 silver badge10 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Turophile Over a year ago

This is one of the rare occasions where DISTINCT is actually the correct answer. Also, if the next question is "how do I make a comma-separated list": stackoverflow.com/questions/7188542/db2-comma-separated-output

Lorenz Meyer · Accepted Answer · 2014-08-12 05:19:29Z

1

Use group_concat and you don't even need a loop. A single query will do it.

select group_concat(distinct id) from table where comment !=''

answered Aug 12, 2014 at 5:19

Lorenz Meyer

20.1k23 gold badges83 silver badges129 bronze badges

4 Comments

abhi Over a year ago

and how to print them

abhi Over a year ago

this may solve my problem but i dont know how to print the the values

abhi Over a year ago

it says call to undefined function :(

Lorenz Meyer Over a year ago

echo mysql_result($result, 0);

Collectives™ on Stack Overflow

mysql query and while loop creating a special string

2 Answers 2

1 Comment

4 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

4 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related